Three stores, three importers and three pickers that differ only in their type are one of each (#85)

Refactoring round one: HttpFontStore/HttpSoundStore/HttpTextureStore collapse into a generic
HttpFileStore over a FileStore contract; fontImport/soundImport/textureImport share assetImport
with an ImportKind per sort; ImagePicker/FontPicker/SoundPicker sit on FilePicker and describe
only their row. The group/comment drag logic leaves GraphCanvas for annotationDrag.ts (with its
own unit test), declaredRows.ts replaces the duplicated row build in particles.ts and shaders.ts,
and dead code in font/sound/compile/emission/transform/actions is gone. README: asset list,
check count 958, the two-job CI, the Scenes wiki page.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

src/core/commands/graphCommands.ts

@@ -15,7 +15,7 @@ import type { Project } from '../model/Project';
 import { coerceValue, defaultsOf } from '../properties/PropertySchema';
 import { type Removed, removeById, removeFirst, removeWhere, restoreAt } from '../util/list';
 import { type Command, CommandError } from './Command';
-import { requireGraph, requireNode, requireNodeDef } from './require';
+import { requireEdge, requireGraph, requireNode, requireNodeDef } from './require';
 import { SetBagValueCommand } from './SetBagValueCommand';
 
 export class AddNodeCommand implements Command {
@@ -221,19 +221,13 @@ export class FoldEdgeCommand implements Command {
   }
 
   execute(project: Project): void {
-    const edge = this.edge(project);
+    const edge = requireEdge(project, this.assetId, this.edgeId);
     this.previous = edge.folded === true;
     this.apply(edge, this.folded);
   }
 
   undo(project: Project): void {
-    this.apply(this.edge(project), this.previous);
-  }
-
-  private edge(project: Project): GraphEdge {
-    const edge = requireGraph(project, this.assetId).edges.find((e) => e.id === this.edgeId);
-    if (!edge) throw new CommandError(`Edge ${this.edgeId} not found`);
-    return edge;
+    this.apply(requireEdge(project, this.assetId, this.edgeId), this.previous);
   }
 
   private apply(edge: GraphEdge, folded: boolean): void {
@@ -254,19 +248,13 @@ export class NameTransitionCommand implements Command {
   ) {}
 
   execute(project: Project): void {
-    const edge = this.edge(project);
+    const edge = requireEdge(project, this.assetId, this.edgeId);
     this.previous = edge.label ?? '';
     this.apply(edge, this.name.trim());
   }
 
   undo(project: Project): void {
-    this.apply(this.edge(project), this.previous);
-  }
-
-  private edge(project: Project): GraphEdge {
-    const edge = requireGraph(project, this.assetId).edges.find((e) => e.id === this.edgeId);
-    if (!edge) throw new CommandError(`Edge ${this.edgeId} not found`);
-    return edge;
+    this.apply(requireEdge(project, this.assetId, this.edgeId), this.previous);
   }
 
   private apply(edge: GraphEdge, name: string): void {

src/core/commands/require.ts

@@ -1,5 +1,5 @@
 /** Lookups that throw a `CommandError` when the target does not exist. */
-import { findNode, type Graph, type GraphNode } from '../graph/Graph';
+import { findNode, type Graph, type GraphEdge, type GraphNode } from '../graph/Graph';
 import { type NodeDef, nodeDef } from '../graph/NodeRegistry';
 import type { Asset, BehaviorAsset, StateMachineAsset, VariablesAsset } from '../model/Asset';
 import { findObject, type ObjectTree } from '../model/hierarchy';
@@ -98,6 +98,12 @@ export function requireNode(project: Project, assetId: string, nodeId: string):
   return node;
 }
 
+export function requireEdge(project: Project, assetId: string, edgeId: string): GraphEdge {
+  const edge = requireGraph(project, assetId).edges.find((e) => e.id === edgeId);
+  if (!edge) throw new CommandError(`Edge ${edgeId} not found`);
+  return edge;
+}
+
 /** A `CommandError`, so an unknown type becomes a notice instead of a crash. */
 export function requireNodeDef(type: string): NodeDef {
   const def = nodeDef(type);

src/core/graph/Graph.ts

@@ -139,6 +139,18 @@ export function edgesOfNode(graph: Graph, nodeId: string): GraphEdge[] {
   return graph.edges.filter((e) => e.from.node === nodeId || e.to.node === nodeId);
 }
 
+/**
+ * What a compiled graph (shader, particles) depends on and nothing else: node ids, types, params
+ * and declared ports, and which port feeds which. Positions, collapsing, folding and the boxes are
+ * the editor's; they stay out so a moved node does not compile again (#65).
+ */
+export function graphFingerprint(graph: Graph): string {
+  return JSON.stringify({
+    nodes: graph.nodes.map((n) => [n.id, n.type, n.params, n.ports ?? null]),
+    edges: graph.edges.map((e) => [e.from.node, e.from.port, e.to.node, e.to.port]),
+  });
+}
+
 export function portsCompatible(from: PortType, to: PortType): boolean {
   if (from === 'exec' || to === 'exec') return from === to;
   return from === to || from === 'any' || to === 'any';

src/core/model/font.ts

@@ -1,4 +1,3 @@
-import type { FontAsset } from './Asset';
 import { findAsset, type Project } from './Project';
 
 /** Mirrors `FontStore::isValidName` on the server, where the name is derived from the bytes. */
@@ -23,7 +22,3 @@ export function fontFileOf(project: Project, id: string): string {
   const asset = findAsset(project, id);
   return asset?.type === 'font' ? asset.file : '';
 }
-
-export function isFontAsset(asset: { type: string }): asset is FontAsset {
-  return asset.type === 'font';
-}

src/core/model/sound.ts

@@ -1,4 +1,3 @@
-import type { SoundAsset } from './Asset';
 import { findAsset, type Project } from './Project';
 
 /** Mirrors `SoundStore::isValidName` on the server, where the name is derived from the bytes. */
@@ -14,7 +13,3 @@ export function soundFileOf(project: Project, id: string): string {
   const asset = findAsset(project, id);
   return asset?.type === 'sound' ? asset.file : '';
 }
-
-export function isSoundAsset(asset: { type: string }): asset is SoundAsset {
-  return asset.type === 'sound';
-}

src/core/particles/compile.ts

@@ -38,18 +38,6 @@ export interface ParticlesBuild {
   reason: string;
 }
 
-/**
- * What the motion depends on and nothing else: node ids, types, params and declared ports, and
- * which port feeds which. Positions and folding are the editor's, so a moved node does not compile
- * again – the same rule the shader fingerprint follows (#65).
- */
-export function particlesFingerprint(graph: Graph): string {
-  return JSON.stringify({
-    nodes: graph.nodes.map((n) => [n.id, n.type, n.params, n.ports ?? null]),
-    edges: graph.edges.map((e) => [e.from.node, e.from.port, e.to.node, e.to.port]),
-  });
-}
-
 /**
  * A particle graph to one function per output: every node reachable from the Output becomes one
  * local per output, in dependency order, so a node feeding two others is evaluated once per

src/core/particles/emission.ts

@@ -74,7 +74,3 @@ export function liveRange(settings: EmitterSettings, time: number, emitUntil = t
   if (oldest > newest) return NO_PARTICLES;
   return { from: Math.max(oldest, newest - Math.floor(max) + 1), to: newest };
 }
-
-export function liveCount(range: LiveRange): number {
-  return Math.max(0, range.to - range.from + 1);
-}

src/core/properties/declaredRows.ts

@@ -0,0 +1,57 @@
+import type { Graph, GraphNode } from '../graph/Graph';
+import type { PropertyBag } from '../model/Properties';
+import type { FlatDef } from './PropertySchema';
+
+/** The params of a `Property` node in a shader or particle graph: its name and the row it declares. */
+export const PROPERTY_NAME_PARAM = 'name';
+export const PROPERTY_DEFAULT_PARAM = 'default';
+export const PROPERTY_MIN_PARAM = 'min';
+export const PROPERTY_MAX_PARAM = 'max';
+
+export interface Declaration {
+  isDeclaration(node: GraphNode): boolean;
+  nameOf(node: GraphNode): string;
+  isValidName(name: string): boolean;
+}
+
+/**
+ * The number rows a graph declares, in node order: one per declaring node with a valid name. A
+ * second node of the same name declares nothing new – both read the one value.
+ */
+export function declaredNumberRows(graph: Graph, of: Declaration): FlatDef<'number'>[] {
+  const rows: FlatDef<'number'>[] = [];
+  const seen = new Set<string>();
+  for (const node of graph.nodes) {
+    if (!of.isDeclaration(node)) continue;
+    const name = of.nameOf(node);
+    if (!of.isValidName(name) || seen.has(name)) continue;
+    seen.add(name);
+    rows.push(numberRow(name, node.params));
+  }
+  return rows;
+}
+
+function numberRow(name: string, params: PropertyBag): FlatDef<'number'> {
+  const min = numberParam(params, PROPERTY_MIN_PARAM, 0);
+  const max = numberParam(params, PROPERTY_MAX_PARAM, 1);
+  const row: FlatDef<'number'> = {
+    key: name,
+    label: name,
+    kind: 'number',
+    default: numberParam(params, PROPERTY_DEFAULT_PARAM, 0),
+    min,
+    step: niceStep(max > min ? max - min : 1),
+  };
+  // A max at or below the min would pin the value; treated as "no max" instead.
+  return max > min ? { ...row, max } : row;
+}
+
+function numberParam(params: PropertyBag, key: string, fallback: number): number {
+  const n = Number(params[key]);
+  return Number.isFinite(n) ? n : fallback;
+}
+
+/** A twentieth of the range's power of ten: 0.05 for 0-4, 0.05 for 0-1, 5 for 0-100. */
+function niceStep(range: number): number {
+  return 10 ** Math.floor(Math.log10(range)) / 20;
+}

src/core/properties/particles.ts

@@ -1,13 +1,17 @@
 import type { Graph, GraphNode } from '../graph/Graph';
 import { type PropertyBag, textOf } from '../model/Properties';
+import { declaredNumberRows, PROPERTY_NAME_PARAM } from './declaredRows';
 import { type FlatDef, isValidFieldName } from './PropertySchema';
 
+export {
+  PROPERTY_DEFAULT_PARAM,
+  PROPERTY_MAX_PARAM,
+  PROPERTY_MIN_PARAM,
+  PROPERTY_NAME_PARAM,
+} from './declaredRows';
+
 /** The node of a particle graph that declares a parameter: a row on every source placed from the asset. */
 export const PARTICLE_PROPERTY = 'ParticleProperty';
-export const PROPERTY_NAME_PARAM = 'name';
-export const PROPERTY_DEFAULT_PARAM = 'default';
-export const PROPERTY_MIN_PARAM = 'min';
-export const PROPERTY_MAX_PARAM = 'max';
 
 /** The rows a particle source has of its own, before the ones its graph declares. */
 export const EMITTING_KEY = 'emitting';
@@ -65,43 +69,11 @@ const RESERVED_KEYS: ReadonlySet<string> = new Set([
   MOVE_WITH_SOURCE_KEY,
 ]);
 
-/**
- * The parameters a particle graph declares, in node order: one number row per `Property` node with
- * a usable name. A second node of the same name declares nothing new – both read the one value.
- */
+/** The parameters a particle graph declares: a row on every source placed from the asset. */
 export function particleParamDefs(graph: Graph): FlatDef<'number'>[] {
-  const rows: FlatDef<'number'>[] = [];
-  const seen = new Set<string>();
-  for (const node of graph.nodes) {
-    if (!isParticlePropertyNode(node)) continue;
-    const name = propertyNameOf(node);
-    if (!isValidParticlePropertyName(name) || seen.has(name)) continue;
-    seen.add(name);
-    rows.push(propertyRow(name, node.params));
-  }
-  return rows;
-}
-
-function propertyRow(name: string, params: PropertyBag): FlatDef<'number'> {
-  const min = numberParam(params, PROPERTY_MIN_PARAM, 0);
-  const max = numberParam(params, PROPERTY_MAX_PARAM, 1);
-  const row: FlatDef<'number'> = {
-    key: name,
-    label: name,
-    kind: 'number',
-    default: numberParam(params, PROPERTY_DEFAULT_PARAM, 0),
-    min,
-    step: niceStep(max > min ? max - min : 1),
-  };
-  // A max at or below the min would pin the value; treated as "no max" instead.
-  return max > min ? { ...row, max } : row;
-}
-
-function numberParam(params: PropertyBag, key: string, fallback: number): number {
-  const n = Number(params[key]);
-  return Number.isFinite(n) ? n : fallback;
-}
-
-function niceStep(range: number): number {
-  return 10 ** Math.floor(Math.log10(range)) / 20;
+  return declaredNumberRows(graph, {
+    isDeclaration: isParticlePropertyNode,
+    nameOf: propertyNameOf,
+    isValidName: isValidParticlePropertyName,
+  });
 }

src/core/properties/shaders.ts

@@ -1,7 +1,15 @@
 import type { Graph, GraphNode } from '../graph/Graph';
 import { type PropertyBag, textOf } from '../model/Properties';
+import { declaredNumberRows, PROPERTY_NAME_PARAM } from './declaredRows';
 import { type FlatDef, isSpriteProp, isValidFieldName } from './PropertySchema';
 
+export {
+  PROPERTY_DEFAULT_PARAM,
+  PROPERTY_MAX_PARAM,
+  PROPERTY_MIN_PARAM,
+  PROPERTY_NAME_PARAM,
+} from './declaredRows';
+
 /** The sprite property naming the shader asset it wears; `''` is no shader and no render pass. */
 export const SHADER_KEY = 'shader';
 
@@ -10,10 +18,6 @@ export const SHADER_KEY = 'shader';
  * GLSL uniform, `default`/`min`/`max` are the row the inspector shows.
  */
 export const SHADER_PROPERTY = 'ShaderProperty';
-export const PROPERTY_NAME_PARAM = 'name';
-export const PROPERTY_DEFAULT_PARAM = 'default';
-export const PROPERTY_MIN_PARAM = 'min';
-export const PROPERTY_MAX_PARAM = 'max';
 
 export function shaderOf(bag: PropertyBag): string {
   return textOf(bag[SHADER_KEY]);
@@ -36,46 +40,13 @@ export function isValidPropertyName(name: string): boolean {
   return isValidFieldName(name) && !isSpriteProp(name);
 }
 
-/**
- * The properties a shader graph declares, in node order: one number row per `Property` node with
- * a valid name. A second node with the same name declares nothing new – both read one uniform.
- */
+/** The properties a shader graph declares: one row on the sprite and one uniform each. */
 export function shaderParamDefs(graph: Graph): FlatDef<'number'>[] {
-  const rows: FlatDef<'number'>[] = [];
-  const seen = new Set<string>();
-  for (const node of graph.nodes) {
-    if (!isPropertyNode(node)) continue;
-    const name = propertyName(node);
-    if (!isValidPropertyName(name) || seen.has(name)) continue;
-    seen.add(name);
-    rows.push(propertyRow(name, node.params));
-  }
-  return rows;
-}
-
-function propertyRow(name: string, params: PropertyBag): FlatDef<'number'> {
-  const min = numberParam(params, PROPERTY_MIN_PARAM, 0);
-  const max = numberParam(params, PROPERTY_MAX_PARAM, 1);
-  const row: FlatDef<'number'> = {
-    key: name,
-    label: name,
-    kind: 'number',
-    default: numberParam(params, PROPERTY_DEFAULT_PARAM, 0),
-    min,
-    step: niceStep(max > min ? max - min : 1),
-  };
-  // A max at or below the min would pin the value; treated as "no max" instead.
-  return max > min ? { ...row, max } : row;
-}
-
-function numberParam(params: PropertyBag, key: string, fallback: number): number {
-  const n = Number(params[key]);
-  return Number.isFinite(n) ? n : fallback;
-}
-
-/** A twentieth of the range's power of ten: 0.05 for 0-4, 0.05 for 0-1, 5 for 0-100. */
-function niceStep(range: number): number {
-  return 10 ** Math.floor(Math.log10(range)) / 20;
+  return declaredNumberRows(graph, {
+    isDeclaration: isPropertyNode,
+    nameOf: propertyName,
+    isValidName: isValidPropertyName,
+  });
 }
 
 /** What a property placed from the palette is called: `value`, then `value2`, `value3` … */

src/core/properties/transform.ts

@@ -99,10 +99,6 @@ export function worldPosition(project: Project, tree: ObjectTree, object: SceneO
   return positionOf(worldTransform(project, tree, object));
 }
 
-export function editorPosition(project: Project, tree: ObjectTree, object: SceneObject): Position {
-  return positionOf(editorTransform(project, tree, object));
-}
-
 /** The world transform of a parent ('' = top level, the identity). */
 export function parentTransform(project: Project, tree: ObjectTree, parentId: string): ChainTransform {
   const parent = parentId ? findObject(tree, parentId) : undefined;

src/core/shader/compile.ts

@@ -54,18 +54,6 @@ export interface ShaderBuild {
  * becomes one local per output, in dependency order, and every Property a float uniform. The texel
  * arrives premultiplied, so the prelude unpremultiplies and the epilogue multiplies back.
  */
-/**
- * What the fragment depends on and nothing else: node ids, types, params and declared ports, and
- * which port feeds which. Positions, collapsing and folding are the editor's; they stay out so a
- * moved node does not compile again (#65).
- */
-export function shaderFingerprint(graph: Graph): string {
-  return JSON.stringify({
-    nodes: graph.nodes.map((n) => [n.id, n.type, n.params, n.ports ?? null]),
-    edges: graph.edges.map((e) => [e.from.node, e.from.port, e.to.node, e.to.port]),
-  });
-}
-
 export function compileShader(graph: Graph): ShaderBuild {
   const problems: Record<string, string> = {};
   const problem = (node: GraphNode, text: string) => {

src/core/store/FileStore.ts

@@ -0,0 +1,28 @@
+/**
+ * What the server answers for an upload: the content-addressed name it stored the bytes under
+ * (`{sha256}.{ext}`, see `isTextureFile`/`isFontFile`/`isSoundFile`) and the caption kept beside it.
+ */
+export interface UploadedFile {
+  file: string;
+  /** The name the file was uploaded under, '' when the server knows none. Never a path. */
+  name: string;
+  bytes: number;
+}
+
+/** A file the server holds, whether any project references it or not. */
+export interface StoredFile extends UploadedFile {
+  updatedAt: string;
+}
+
+/**
+ * Raw bytes rather than a multipart form: the server derives name and format from the file itself,
+ * so there is nothing else to send. `type` only fills the Content-Type header – the server trusts
+ * the bytes, not the label – and uploading the same bytes twice yields the same file, the hash of
+ * its content. `name` is the caption kept beside it; uploading the same bytes under a new name
+ * renames what the pickers show.
+ */
+export interface FileStore<U extends UploadedFile = UploadedFile, S extends StoredFile = StoredFile> {
+  upload(bytes: Blob | ArrayBuffer, type: string, name?: string): Promise<U>;
+  list(): Promise<S[]>;
+  delete(file: string): Promise<void>;
+}

src/core/store/FontStore.ts

@@ -1,26 +1,9 @@
-export interface UploadedFont {
-  /** Content-addressed name in `data/fonts/`: `{sha256}.{ttf|otf|woff|woff2}` (see `isFontFile`). */
-  file: string;
-  /** The name the file was uploaded under, '' when the server knows none. Never a path. */
-  name: string;
-  bytes: number;
-}
-
-/** A typeface the server holds, whether any project references it or not. */
-export interface StoredFont {
-  file: string;
-  name: string;
-  bytes: number;
-  updatedAt: string;
-}
+import type { FileStore, StoredFile, UploadedFile } from './FileStore';
 
 /**
- * Raw bytes, like an image upload: the server derives name and format from the file itself. Unlike
- * an image a font is never re-encoded on the way, so what the server stores is what was picked.
+ * Stored in `data/fonts/` as `{sha256}.{ttf|otf|woff|woff2}`. Unlike an image a font is never
+ * re-encoded on the way, so what the server stores is what was picked.
  */
-export interface FontStore {
-  /** `name` is kept beside the file as its caption; the stored file is always the hash. */
-  upload(bytes: Blob | ArrayBuffer, type: string, name?: string): Promise<UploadedFont>;
-  list(): Promise<StoredFont[]>;
-  delete(file: string): Promise<void>;
-}
+export type UploadedFont = UploadedFile;
+export type StoredFont = StoredFile;
+export type FontStore = FileStore<UploadedFont, StoredFont>;

src/core/store/HttpFileStore.ts

@@ -0,0 +1,31 @@
+import type { FileStore, StoredFile, UploadedFile } from './FileStore';
+import { apiRequest } from './http';
+
+/** The API's three file collections, one route each; textures, fonts and sounds differ in nothing else. */
+export type FileRoute = 'textures' | 'fonts' | 'sounds';
+
+export class HttpFileStore<
+  U extends UploadedFile = UploadedFile,
+  S extends StoredFile = StoredFile,
+> implements FileStore<U, S> {
+  constructor(
+    private readonly endpoint: string,
+    private readonly route: FileRoute,
+  ) {}
+
+  async upload(bytes: Blob | ArrayBuffer, type: string, name = ''): Promise<U> {
+    return apiRequest<U>(this.endpoint, 'POST', this.route, {
+      headers: { 'Content-Type': type },
+      body: bytes,
+      query: { name },
+    });
+  }
+
+  async list(): Promise<S[]> {
+    return apiRequest<S[]>(this.endpoint, 'GET', this.route, {});
+  }
+
+  async delete(file: string): Promise<void> {
+    await apiRequest<void>(this.endpoint, 'DELETE', `${this.route}/${encodeURIComponent(file)}`, {});
+  }
+}

src/core/store/HttpFontStore.ts

@@ -1,30 +0,0 @@
-import type { FontStore, StoredFont, UploadedFont } from './FontStore';
-import { apiRequest } from './http';
-
-export class HttpFontStore implements FontStore {
-  constructor(private readonly endpoint: string) {}
-
-  async upload(bytes: Blob | ArrayBuffer, type: string, name = ''): Promise<UploadedFont> {
-    return this.request<UploadedFont>('POST', 'fonts', { bytes, type, name });
-  }
-
-  async list(): Promise<StoredFont[]> {
-    return this.request<StoredFont[]>('GET', 'fonts');
-  }
-
-  async delete(file: string): Promise<void> {
-    await this.request<void>('DELETE', `fonts/${encodeURIComponent(file)}`);
-  }
-
-  private async request<T>(
-    method: string,
-    route: string,
-    payload?: { bytes: Blob | ArrayBuffer; type: string; name: string },
-  ): Promise<T> {
-    return apiRequest<T>(this.endpoint, method, route, {
-      headers: payload ? { 'Content-Type': payload.type } : {},
-      body: payload?.bytes,
-      query: payload ? { name: payload.name } : undefined,
-    });
-  }
-}

src/core/store/HttpSoundStore.ts

@@ -1,30 +0,0 @@
-import { apiRequest } from './http';
-import type { SoundStore, StoredSound, UploadedSound } from './SoundStore';
-
-export class HttpSoundStore implements SoundStore {
-  constructor(private readonly endpoint: string) {}
-
-  async upload(bytes: Blob | ArrayBuffer, type: string, name = ''): Promise<UploadedSound> {
-    return this.request<UploadedSound>('POST', 'sounds', { bytes, type, name });
-  }
-
-  async list(): Promise<StoredSound[]> {
-    return this.request<StoredSound[]>('GET', 'sounds');
-  }
-
-  async delete(file: string): Promise<void> {
-    await this.request<void>('DELETE', `sounds/${encodeURIComponent(file)}`);
-  }
-
-  private async request<T>(
-    method: string,
-    route: string,
-    payload?: { bytes: Blob | ArrayBuffer; type: string; name: string },
-  ): Promise<T> {
-    return apiRequest<T>(this.endpoint, method, route, {
-      headers: payload ? { 'Content-Type': payload.type } : {},
-      body: payload?.bytes,
-      query: payload ? { name: payload.name } : undefined,
-    });
-  }
-}

src/core/store/HttpTextureStore.ts

@@ -1,30 +0,0 @@
-import { apiRequest } from './http';
-import type { StoredTexture, TextureStore, UploadedTexture } from './TextureStore';
-
-export class HttpTextureStore implements TextureStore {
-  constructor(private readonly endpoint: string) {}
-
-  async upload(bytes: Blob | ArrayBuffer, type: string, name = ''): Promise<UploadedTexture> {
-    return this.request<UploadedTexture>('POST', 'textures', { bytes, type, name });
-  }
-
-  async list(): Promise<StoredTexture[]> {
-    return this.request<StoredTexture[]>('GET', 'textures');
-  }
-
-  async delete(file: string): Promise<void> {
-    await this.request<void>('DELETE', `textures/${encodeURIComponent(file)}`);
-  }
-
-  private async request<T>(
-    method: string,
-    route: string,
-    payload?: { bytes: Blob | ArrayBuffer; type: string; name: string },
-  ): Promise<T> {
-    return apiRequest<T>(this.endpoint, method, route, {
-      headers: payload ? { 'Content-Type': payload.type } : {},
-      body: payload?.bytes,
-      query: payload ? { name: payload.name } : undefined,
-    });
-  }
-}

src/core/store/SoundStore.ts

@@ -1,27 +1,9 @@
-export interface UploadedSound {
-  /** Content-addressed name in `data/sounds/`: `{sha256}.{mp3|ogg|wav|m4a}` (see `isSoundFile`). */
-  file: string;
-  /** The name the file was uploaded under, '' when the server knows none. Never a path. */
-  name: string;
-  bytes: number;
-}
-
-/** A sound the server holds, whether any project references it or not. */
-export interface StoredSound {
-  file: string;
-  name: string;
-  bytes: number;
-  updatedAt: string;
-}
+import type { FileStore, StoredFile, UploadedFile } from './FileStore';
 
 /**
- * Raw bytes, like a font upload: the server derives name and format from the file itself. A sound
- * is never re-encoded on the way, so what the server stores is what was picked – and how long it
+ * Stored in `data/sounds/` as `{sha256}.{mp3|ogg|wav|m4a}`, never re-encoded. How long a sound
  * plays is nowhere in here, because only a decoder knows that.
  */
-export interface SoundStore {
-  /** `name` is kept beside the file as its caption; the stored file is always the hash. */
-  upload(bytes: Blob | ArrayBuffer, type: string, name?: string): Promise<UploadedSound>;
-  list(): Promise<StoredSound[]>;
-  delete(file: string): Promise<void>;
-}
+export type UploadedSound = UploadedFile;
+export type StoredSound = StoredFile;
+export type SoundStore = FileStore<UploadedSound, StoredSound>;

src/core/store/TextureStore.ts

@@ -1,38 +1,18 @@
-export interface UploadedTexture {
-  /** Content-addressed name in `data/textures/`: `{sha256}.{png|jpg|webp|gif}` (see `isTextureFile`). */
-  file: string;
-  /**
-   * The name the file was uploaded under, '' when the server knows none. A picture may be
-   * re-encoded on the way, so this can be a `.png` name on a file stored as `.webp`.
-   */
-  name: string;
+import type { FileStore, StoredFile, UploadedFile } from './FileStore';
+
+/**
+ * Stored in `data/textures/` as `{sha256}.{png|jpg|webp|gif}`. A picture may be re-encoded on the
+ * way, so `name` can be a `.png` name on a file stored as `.webp`.
+ */
+export interface UploadedTexture extends UploadedFile {
   width: number;
   height: number;
-  bytes: number;
 }
 
-/** A file the server holds, whether any project references it or not. */
-export interface StoredTexture {
-  file: string;
-  name: string;
+export interface StoredTexture extends StoredFile {
   /** 0 × 0 when the server could not read the header; such a file cannot become an asset. */
   width: number;
   height: number;
-  bytes: number;
-  updatedAt: string;
 }
 
-/**
- * An upload is raw bytes rather than a multipart form: name, size and format are derived from the
- * image itself on the server, so there is nothing else to send.
- */
-export interface TextureStore {
-  /**
-   * `type` only fills the Content-Type header – the server trusts the bytes, not the label – and
-   * uploading the same picture twice yields the same file, the hash of its content. `name` is the
-   * caption kept beside it; uploading the same bytes under a new name renames what pickers show.
-   */
-  upload(bytes: Blob | ArrayBuffer, type: string, name?: string): Promise<UploadedTexture>;
-  list(): Promise<StoredTexture[]>;
-  delete(file: string): Promise<void>;
-}
+export type TextureStore = FileStore<UploadedTexture, StoredTexture>;

src/editor/App.ts

@@ -1,8 +1,7 @@
 import type { Application } from 'pixi.js';
-import { HttpFontStore } from '../core/store/HttpFontStore';
+import { HttpFileStore } from '../core/store/HttpFileStore';
 import { HttpProjectStore } from '../core/store/HttpProjectStore';
-import { HttpSoundStore } from '../core/store/HttpSoundStore';
-import { HttpTextureStore } from '../core/store/HttpTextureStore';
+import type { StoredTexture, UploadedTexture } from '../core/store/TextureStore';
 import { requestRender, type VStack } from '../ui';
 import { fontLibrary } from '../viewport/FontLibrary';
 import { soundLibrary } from '../viewport/SoundLibrary';
@@ -32,9 +31,9 @@ export async function startEditor(app: Application, root: VStack): Promise<void>
     root,
     state,
     new HttpProjectStore(API_ENDPOINT),
-    new HttpTextureStore(API_ENDPOINT),
-    new HttpFontStore(API_ENDPOINT),
-    new HttpSoundStore(API_ENDPOINT),
+    new HttpFileStore<UploadedTexture, StoredTexture>(API_ENDPOINT, 'textures'),
+    new HttpFileStore(API_ENDPOINT, 'fonts'),
+    new HttpFileStore(API_ENDPOINT, 'sounds'),
   );
   // An image or a font arrives long after the click that asked for it, and the widget waiting for
   // it repaints without telling anyone: both libraries are a wake-up of their own.

src/editor/FilePicker.ts

@@ -0,0 +1,338 @@
+/**
+ * The dialog behind "+ → Texture / Font / Sound": everything the server holds of one kind, with
+ * what the project already calls it. Offering the server's files rather than the machine's is the
+ * point – uploading the same file twice is wasteful, and nothing collects the files a project
+ * stopped referencing. Uploading is still one button away.
+ *
+ * The list differs per kind (tiles for pictures, rows with a sample line for typefaces, rows with a
+ * ▶ for sounds); the dialog around it does not.
+ */
+import { type Container, type FederatedPointerEvent, type Graphics, Text } from 'pixi.js';
+import type { AssetType } from '../core/model/AssetTypes';
+import type { Project } from '../core/model/Project';
+import type { StoredFile } from '../core/store/FileStore';
+import {
+  Button,
+  drawControlBox,
+  formatBytes,
+  HStack,
+  Label,
+  Popup,
+  pressCount,
+  ScrollContainer,
+  Spacer,
+  Theme,
+  textStyle,
+  Widget,
+} from '../ui';
+
+/** The dialog keeps this size whatever the list turns out to be, so it does not jump on opening. */
+export const PICKER_WIDTH = 560;
+export const PICKER_HEIGHT = 340;
+
+/** One offered file, with the asset that already wears it (if any). */
+export type PickerItem<S extends StoredFile = StoredFile> = S & { assetName: string | null };
+
+/** Pairs what the server lists with what the project calls it – the asset name is the caption worth showing. */
+export function withAssetNames<S extends StoredFile>(
+  stored: S[],
+  project: Project,
+  type: AssetType,
+): PickerItem<S>[] {
+  const named = new Map<string, string>();
+  for (const asset of project.assets) {
+    if (asset.type === type && 'file' in asset) named.set(asset.file, asset.name);
+  }
+  return stored.map((item) => ({ ...item, assetName: named.get(item.file) ?? null }));
+}
+
+/** The line under the list for a picked file: its upload name and size, and who wears it. */
+export function describeStored(item: PickerItem): string {
+  const size = item.name ? `${item.name} – ${formatBytes(item.bytes)}` : formatBytes(item.bytes);
+  return item.assetName ? `${size} – already in the project as "${item.assetName}"` : size;
+}
+
+export interface PickerRow {
+  /** A Container holding the rest, not a Graphics with children: Pixi v8 only lets containers have them. */
+  box: Container;
+  background: Graphics;
+  caption: Text;
+}
+
+/**
+ * The selectable part of the dialog: one entry per file, one of them picked, a double press
+ * confirms. How entries are built, placed and drawn is the subclass's.
+ */
+export abstract class PickerList<Item extends PickerItem, Row extends PickerRow> extends Widget {
+  protected items: Item[] = [];
+  protected rows: Row[] = [];
+  private selectedFile: string | null = null;
+  private readonly empty = new Text({ text: '', style: textStyle('muted') });
+  private readonly unwatch: (() => void)[] = [];
+  onPick?: (file: string) => void;
+  onActivate?: (file: string) => void;
+  emptyText = '';
+
+  constructor() {
+    super();
+    this.addChild(this.empty);
+    this.on('pointerdown', (e: FederatedPointerEvent) => this.onPress(e));
+  }
+
+  /** Redraws whenever a library reports an arrival, until the list is destroyed. */
+  protected watch(library: { onChange(fn: () => void): () => void }, onArrive: () => void): void {
+    this.unwatch.push(library.onChange(onArrive));
+  }
+
+  setItems(items: Item[]): void {
+    this.items = items;
+    for (const row of this.rows) row.box.destroy({ children: true });
+    this.rows = items.map(() => {
+      const row = this.buildRow();
+      this.addChild(row.box);
+      return row;
+    });
+    if (!items.some((item) => item.file === this.selectedFile)) this.selectedFile = null;
+    this.layout();
+    this.redraw();
+  }
+
+  get selected(): Item | null {
+    return this.items.find((item) => item.file === this.selectedFile) ?? null;
+  }
+
+  get fileList(): string[] {
+    return this.items.map((item) => item.file);
+  }
+
+  get usedFiles(): string[] {
+    return this.items.filter((item) => item.assetName !== null).map((item) => item.file);
+  }
+
+  /** The captions as drawn, read off the rows themselves rather than recomputed (test hook). */
+  get captions(): string[] {
+    return this.rows.map((row) => row.caption.text);
+  }
+
+  select(file: string | null): void {
+    if (file === this.selectedFile) return;
+    this.selectedFile = file;
+    this.redraw();
+    if (file) this.onPick?.(file);
+  }
+
+  /** The row of a file, with its index; null when the file is not offered. */
+  protected rowOf(file: string): { row: Row; index: number } | null {
+    const index = this.items.findIndex((item) => item.file === file);
+    const row = this.rows[index];
+    return row ? { row, index } : null;
+  }
+
+  override redraw(): void {
+    this.empty.text = this.items.length === 0 ? this.emptyText : '';
+    this.empty.position.set(0, 0);
+    this.rows.forEach((row, index) => {
+      const item = this.items[index];
+      if (item) this.redrawRow(row, item, item.file === this.selectedFile);
+    });
+  }
+
+  override destroy(): void {
+    for (const stop of this.unwatch) stop();
+    super.destroy({ children: true });
+  }
+
+  protected drawBox(row: Row, w: number, h: number, selected: boolean): void {
+    row.background.clear();
+    drawControlBox(row.background, w, h, {
+      fill: selected ? Theme.colors.selection : Theme.colors.control,
+      border: selected ? Theme.colors.accent : Theme.colors.border,
+    });
+  }
+
+  protected onPress(e: FederatedPointerEvent): void {
+    const local = this.toLocal(e.global);
+    const item = this.items[this.indexAt(local.x, local.y)];
+    if (!item) return;
+    this.select(item.file);
+    if (pressCount(e, item.file) === 2) this.onActivate?.(item.file);
+  }
+
+  protected abstract buildRow(): Row;
+  /** Which entry a local point is on; any index without an item means none. */
+  protected abstract indexAt(x: number, y: number): number;
+  protected abstract redrawRow(row: Row, item: Item, selected: boolean): void;
+}
+
+/** A list of equally tall rows, one under the other. */
+export abstract class RowList<Item extends PickerItem, Row extends PickerRow> extends PickerList<Item, Row> {
+  protected abstract readonly rowHeight: number;
+  protected readonly rowGap = 4;
+
+  /** Global centre of a row (test hook); `fromX` keeps clear of a column that does something else. */
+  rowGlobal(file: string, fromX = 0): { x: number; y: number } | null {
+    const found = this.rowOf(file);
+    if (!found) return null;
+    const p = found.row.box.getGlobalPosition();
+    return { x: p.x + fromX + (this.w - fromX) / 2, y: p.y + this.rowHeight / 2 };
+  }
+
+  heightFor(count: number): number {
+    return count === 0 ? 0 : count * this.rowHeight + (count - 1) * this.rowGap;
+  }
+
+  override measure(): { w: number; h: number } {
+    return { w: this.minWidth, h: Math.max(this.minHeight, this.heightFor(this.items.length)) };
+  }
+
+  override layout(): void {
+    this.rows.forEach((row, index) => row.box.position.set(0, index * (this.rowHeight + this.rowGap)));
+  }
+
+  protected override indexAt(x: number, y: number): number {
+    return x >= 0 && x <= this.w ? Math.floor(y / (this.rowHeight + this.rowGap)) : -1;
+  }
+}
+
+export interface PickerWords {
+  title: string;
+  loading: string;
+  /** Under the list while nothing is picked; a hint for what the rows can do. */
+  idle?: string;
+  empty: string;
+  use: string;
+  /** "image", "font", "sound" – for "3 fonts on the server". */
+  noun: string;
+}
+
+let current: FilePicker<PickerItem> | null = null;
+
+/**
+ * Opens the dialog centred, closing whichever picker was open before it, and starts the listing.
+ * The listing starts here and not in the constructor: it asks the subclass, and a subclass's own
+ * fields are not assigned until its constructor has run past `super()`.
+ */
+export function openPicker<P extends FilePicker<PickerItem>>(picker: P): P {
+  current?.close();
+  current = picker;
+  picker.openCentered();
+  void picker.load();
+  return picker;
+}
+
+/** The open dialog if it is one of `kind`, for the test hooks. */
+export function currentPicker<P extends FilePicker<PickerItem>>(
+  kind: abstract new (...args: never[]) => P,
+): P | null {
+  return current instanceof kind ? current : null;
+}
+
+export abstract class FilePicker<Item extends PickerItem> extends Popup {
+  protected readonly scroll = new ScrollContainer();
+  private readonly status: Label;
+  private readonly detail: Label;
+  private readonly use: Button;
+
+  constructor(
+    protected readonly list: PickerList<Item, PickerRow>,
+    private readonly words: PickerWords,
+    upload: () => void,
+  ) {
+    super({ modal: true, padding: Theme.padding * 2, gap: Theme.gap });
+    this.content.add(new Label(words.title, { style: 'bodyBold' }));
+    this.status = new Label(words.loading, { style: 'muted' });
+    this.content.add(this.status);
+
+    list.minWidth = PICKER_WIDTH;
+    list.emptyText = words.empty;
+    list.onPick = () => this.refreshSelection();
+    list.onActivate = () => this.confirm();
+    this.scroll.minWidth = PICKER_WIDTH;
+    this.scroll.minHeight = PICKER_HEIGHT;
+    this.scroll.setContent(list);
+    this.content.add(this.scroll);
+
+    this.detail = new Label(words.idle ?? '', { style: 'muted' });
+    this.content.add(this.detail);
+
+    const buttons = new HStack({ gap: Theme.gap, align: 'center' });
+    const uploadButton = new Button('Upload…');
+    uploadButton.onClick = this.closeThen(upload);
+    buttons.add(uploadButton);
+    buttons.add(new Spacer(), 1);
+    const cancel = new Button('Cancel');
+    cancel.onClick = this.closeThen();
+    buttons.add(cancel);
+    this.use = new Button(words.use, { variant: 'primary' });
+    this.use.onClick = () => this.confirm();
+    this.use.setEnabled(false);
+    buttons.add(this.use);
+    this.content.add(buttons);
+  }
+
+  /** What the dialog offers, which of it the project already wears, and what is picked (test hook). */
+  debugInfo(): { files: string[]; used: string[]; captions: string[]; selected: string | null } {
+    return {
+      files: this.list.fileList,
+      used: this.list.usedFiles,
+      captions: this.list.captions,
+      selected: this.list.selected?.file ?? null,
+    };
+  }
+
+  override close(): void {
+    super.close();
+    if (current === this) current = null;
+    // Escape, Cancel and a confirmed pick all land here, and `Popup.close` tolerates a second
+    // call; the list's listeners must be dropped exactly once.
+    if (!this.list.destroyed) this.list.destroy();
+  }
+
+  async load(): Promise<void> {
+    try {
+      const items = await this.fetchItems();
+      this.list.setItems(items);
+      // Only as tall as the entries need, up to the cap: a handful of files should not leave half
+      // a dialog of empty box under them.
+      const { unit, total } = this.contentHeight(items.length);
+      this.scroll.minHeight = Math.min(this.roomFor(this.scroll, unit), Math.max(unit, total));
+      const { noun } = this.words;
+      this.status.setText(
+        items.length === 1 ? `1 ${noun} on the server` : `${items.length} ${noun}s on the server`,
+      );
+    } catch (error) {
+      this.status.setText(
+        `Could not list the ${this.words.noun}s: ${error instanceof Error ? error.message : String(error)}`,
+      );
+    }
+    this.refreshSelection();
+  }
+
+  private refreshSelection(): void {
+    const item = this.list.selected;
+    this.use.setEnabled(item !== null && this.canUse(item));
+    this.detail.setText(item ? this.describe(item) : (this.words.idle ?? ''));
+    this.refreshLayout();
+  }
+
+  private confirm(): void {
+    const item = this.list.selected;
+    if (!item || !this.canUse(item)) return;
+    this.close();
+    this.adopt(item);
+  }
+
+  /** The server's list, paired with the project's names (`withAssetNames`). */
+  protected abstract fetchItems(): Promise<Item[]>;
+  /** How tall the list is for `count` entries, and the height of one – the least the scroll shows. */
+  protected abstract contentHeight(count: number): { unit: number; total: number };
+  protected abstract adopt(item: Item): void;
+
+  protected canUse(_item: Item): boolean {
+    return true;
+  }
+
+  protected describe(item: Item): string {
+    return describeStored(item);
+  }
+}

src/editor/actions.ts

@@ -58,16 +58,6 @@ export function removeNodes(state: EditorState, assetId: string, nodeIds: readon
   return commands.length > 0 && state.execute(oneStep(`Delete ${commands.length} nodes`, commands));
 }
 
-/**
- * Deletes a group or comment and leaves every node alone – which is the point, so the caller does
- * not have to know which of the two lists holds it either.
- */
-export function removeAnnotation(state: EditorState, assetId: string, annotationId: string): boolean {
-  const graph = findGraphAsset(state.project, assetId)?.graph;
-  const found = graph && findAnnotation(graph, annotationId);
-  return Boolean(found) && state.execute(new RemoveAnnotationCommand(assetId, found!.kind, annotationId));
-}
-
 /**
  * Deletes everything a graph selection holds – nodes and boxes alike – as one undo step, since one
  * band caught them and one keypress asked for them to go. Boxes still take none of their nodes.

src/editor/assetImport.ts

@@ -0,0 +1,178 @@
+/**
+ * Pictures, typefaces and sounds all arrive the same way: a file goes up to the server, comes back
+ * as a content-addressed name, and an asset is made for it – or the asset already naming those
+ * bytes is used. What differs between them is an `ImportKind`; the pipeline is this file.
+ */
+import type { Command } from '../core/commands/Command';
+import { nextAssetName } from '../core/commands/naming';
+import type { AssetType } from '../core/model/AssetTypes';
+import type { FileStore, UploadedFile } from '../core/store/FileStore';
+import type { EditorState } from './state';
+
+/** One file's outcome; exactly one of `assetId` and `error` is set. */
+export interface ImportOutcome {
+  name: string;
+  assetId: string | null;
+  error: string | null;
+  /** The project already had this exact file, so its existing asset was used instead. */
+  reused?: boolean;
+}
+
+export interface ImportDeps {
+  state: EditorState;
+}
+
+export interface ImportKind<U extends UploadedFile, D extends ImportDeps> {
+  type: AssetType;
+  /** What the notices call one: "image", "font", "sound". */
+  noun: string;
+  /** What an asset is called when the file name gives nothing to go on. */
+  fallbackName: string;
+  store(deps: D): FileStore<U>;
+  /** The bytes to send, and their Content-Type; throws with the reason when the file cannot go up. */
+  prepare(file: File): Promise<{ blob: Blob; type: string }>;
+  create(name: string, uploaded: U): Command & { asset: { id: string } };
+}
+
+/**
+ * Imports the files sequentially, so each asset is named against the project as the previous one
+ * left it. A file that fails is reported in the notice; the remaining ones are still imported.
+ */
+export async function importFiles<U extends UploadedFile, D extends ImportDeps>(
+  kind: ImportKind<U, D>,
+  files: readonly File[],
+  deps: D,
+): Promise<ImportOutcome[]> {
+  if (files.length === 0) return [];
+  const outcomes: ImportOutcome[] = [];
+  for (const file of files) outcomes.push(await importFile(kind, file, deps));
+  // The asset the batch created last, so the panel shows what just arrived.
+  const created = outcomes.filter((outcome) => outcome.assetId !== null);
+  const last = created[created.length - 1];
+  if (last?.assetId) deps.state.select({ kind: 'asset', assetId: last.assetId });
+  deps.state.setNotice(importNotice(outcomes, kind.noun));
+  return outcomes;
+}
+
+async function importFile<U extends UploadedFile, D extends ImportDeps>(
+  kind: ImportKind<U, D>,
+  file: File,
+  deps: D,
+): Promise<ImportOutcome> {
+  try {
+    const { blob, type } = await kind.prepare(file);
+    const uploaded = await kind.store(deps).upload(blob, type, file.name);
+    return adopt(kind, uploaded, assetNameForFile(file.name, kind.fallbackName), file.name, deps);
+  } catch (error) {
+    return { name: file.name, assetId: null, error: error instanceof Error ? error.message : String(error) };
+  }
+}
+
+/**
+ * Makes an asset for a file the server holds. `label` names the source in messages, `nameBase` is
+ * what the asset is called. The server stores by content hash, so a re-imported file comes back
+ * as the one the project already references; two assets on one file would disagree about it.
+ */
+function adopt<U extends UploadedFile, D extends ImportDeps>(
+  kind: ImportKind<U, D>,
+  uploaded: U,
+  nameBase: string,
+  label: string,
+  deps: D,
+): ImportOutcome {
+  const existing = deps.state.project.assets.find(
+    (a) => a.type === kind.type && 'file' in a && a.file === uploaded.file,
+  );
+  if (existing) return { name: label, assetId: existing.id, error: null, reused: true };
+
+  const command = kind.create(nextAssetName(deps.state.project, nameBase), uploaded);
+  // A rejected command has already put its reason into the notice; that is the message here.
+  if (!deps.state.execute(command)) return { name: label, assetId: null, error: deps.state.notice };
+  return { name: label, assetId: command.asset.id, error: null, reused: false };
+}
+
+/**
+ * Adopts a file the server already holds – no upload, the bytes are there. Nothing collects
+ * unreferenced files, so one project's dropped picture is still there for the next to pick up.
+ * Chosen in the picker, so this is "+ → Texture": the tab opens like for any created asset (a kind
+ * without a tab is just selected). A dropped file only selects – it usually goes into the scene.
+ */
+export function importStored<U extends UploadedFile, D extends ImportDeps>(
+  kind: ImportKind<U, D>,
+  uploaded: U,
+  deps: D,
+): ImportOutcome {
+  // Named after the file it was uploaded as, like a dropped one; a file from before names were
+  // kept has none and falls back to the kind's own word.
+  const nameBase = assetNameForFile(uploaded.name, kind.fallbackName);
+  const outcome = adopt(kind, uploaded, nameBase, uploaded.name || uploaded.file, deps);
+  if (outcome.assetId) deps.state.openAsset(outcome.assetId);
+  deps.state.setNotice(
+    outcome.error ??
+      (outcome.reused
+        ? `That ${kind.noun} is already in the project.`
+        : `Added the ${kind.noun} to the project.`),
+  );
+  return outcome;
+}
+
+/** One line for the whole batch; reuse is worded apart, since "Imported 1 image" would be a lie. */
+export function importNotice(outcomes: readonly ImportOutcome[], noun = 'image'): string {
+  const added = outcomes.filter((outcome) => outcome.assetId !== null && !outcome.reused).length;
+  const reused = outcomes.filter((outcome) => outcome.reused).length;
+  const failed = outcomes.filter((outcome) => outcome.error !== null);
+  const first = failed[0];
+
+  const known = reused === 0 ? '' : ` ${reused === 1 ? 'One was' : `${reused} were`} already in the project.`;
+
+  if (!first) {
+    if (added === 0 && reused > 0)
+      return reused === 1
+        ? `That ${noun} is already in the project.`
+        : `Those ${reused} ${noun}s are already in the project.`;
+    return `Imported ${added} ${added === 1 ? noun : `${noun}s`}.${known}`;
+  }
+  const more = failed.length > 1 ? ` (and ${failed.length - 1} more)` : '';
+  const problem = `Could not import "${first.name}": ${first.error ?? ''}${more}`;
+  if (added + reused === 0) return problem;
+  return `Imported ${added + reused} of ${outcomes.length}.${known} ${problem}`;
+}
+
+/**
+ * A file name without its extension, as an asset is called: "hero-idle.png" reads better than
+ * "Texture 3". The picker gets the same name back from the server.
+ */
+export function assetNameForFile(fileName: string, fallback: string): string {
+  return fileName.replace(/\.[^.]+$/, '').trim() || fallback;
+}
+
+/** Opens the browser's file dialog; resolves empty when the dialog was cancelled. */
+export function pickFiles(accept: string): Promise<File[]> {
+  return new Promise((resolve) => {
+    const input = document.createElement('input');
+    input.type = 'file';
+    input.accept = accept;
+    input.multiple = true;
+    input.style.display = 'none';
+    document.body.appendChild(input);
+    const finish = (files: File[]) => {
+      input.remove();
+      resolve(files);
+    };
+    input.addEventListener('change', () => finish([...(input.files ?? [])]));
+    // Without `cancel` a dismissed dialog leaves both the element and this promise behind.
+    input.addEventListener('cancel', () => finish([]));
+    input.click();
+  });
+}
+
+/** The *Upload…* button: the file dialog, then the batch import of whatever it returns. */
+export function pickAndImport<U extends UploadedFile, D extends ImportDeps>(
+  kind: ImportKind<U, D>,
+  accept: string,
+  deps: D,
+): void {
+  void pickFiles(accept)
+    .then((files) => importFiles(kind, files, deps))
+    .catch((error: unknown) => deps.state.setNotice(String(error), 'error'));
+}

src/editor/font/FontPicker.ts

@@ -1,296 +1,110 @@
-import { Container, type FederatedPointerEvent, Graphics, Text, TextStyle } from 'pixi.js';
+import { Container, Graphics, Text, TextStyle } from 'pixi.js';
 import type { StoredFont } from '../../core/store/FontStore';
-import {
-  Button,
-  drawControlBox,
-  formatBytes,
-  HStack,
-  Label,
-  Popup,
-  pressCount,
-  ScrollContainer,
-  type Size,
-  Spacer,
-  Theme,
-  textStyle,
-  truncate,
-  Widget,
-} from '../../ui';
+import { formatBytes, Theme, textStyle, truncate } from '../../ui';
 import { fontLibrary } from '../../viewport/FontLibrary';
+import {
+  currentPicker,
+  FilePicker,
+  openPicker,
+  type PickerItem,
+  type PickerRow,
+  RowList,
+  withAssetNames,
+} from '../FilePicker';
 import { type FontImportDeps, importStoredFont, pickAndImportFonts } from '../fontImport';
 
-/** The dialog keeps this size whatever the list turns out to be, so it does not jump on opening. */
-const LIST_WIDTH = 560;
-const LIST_HEIGHT = 340;
 const ROW_HEIGHT = 52;
-const ROW_GAP = 4;
 const ROW_PAD = 8;
 /** Big enough to tell two typefaces apart at a glance, small enough for a long line to fit. */
 const SAMPLE_SIZE = 22;
 const SAMPLE_TEXT = 'Aa Bb Cc  0123  The quick brown fox';
 
-/** One offered typeface, with the asset that already wears it (if any). */
-interface PickerItem extends StoredFont {
-  assetName: string | null;
+type FontItem = PickerItem<StoredFont>;
+interface FontRow extends PickerRow {
+  sample: Text;
 }
 
 /**
- * The rows. A typeface has no thumbnail to show, so each row *is* the preview: the sample line is
- * drawn in the face itself, and reflows from the fallback once the library has loaded it.
+ * A typeface has no thumbnail to show, so each row *is* the preview: the sample line is drawn in
+ * the face itself, and reflows from the fallback once the library has loaded it.
  */
-class FontList extends Widget {
-  private items: PickerItem[] = [];
-  private rows: { box: Container; background: Graphics; sample: Text; caption: Text }[] = [];
-  private selectedFile: string | null = null;
-  private readonly empty = new Text({ text: '', style: textStyle('muted') });
-  private readonly stopWatching: () => void;
-  onPick?: (file: string) => void;
-  onActivate?: (file: string) => void;
-  emptyText = '';
+class FontList extends RowList<FontItem, FontRow> {
+  protected readonly rowHeight = ROW_HEIGHT;
 
   constructor() {
     super();
-    this.addChild(this.empty);
-    this.on('pointerdown', (e: FederatedPointerEvent) => this.onPress(e));
-    this.stopWatching = fontLibrary.onChange(() => this.redraw());
+    this.watch(fontLibrary, () => this.redraw());
   }
 
-  setItems(items: PickerItem[]): void {
-    this.items = items;
-    for (const row of this.rows) row.box.destroy({ children: true });
-    this.rows = items.map(() => {
-      // A Container holding the background, not a Graphics with children: Pixi v8 only lets
-      // containers have them (`addChild: Only Containers will be allowed to add children`).
-      const box = new Container();
-      const background = new Graphics();
-      // Its own style object, never `textStyle('body')`: those are shared across the whole
-      // editor, so writing a family into one would restyle every label in the window.
-      const sample = new Text({
-        style: new TextStyle({ fontSize: SAMPLE_SIZE, fill: Theme.colors.text }),
-      });
-      const caption = new Text({ style: textStyle('small') });
-      box.addChild(background, sample, caption);
-      this.addChild(box);
-      return { box, background, sample, caption };
-    });
-    if (!items.some((item) => item.file === this.selectedFile)) this.selectedFile = null;
-    this.layout();
-    this.redraw();
+  protected buildRow(): FontRow {
+    const box = new Container();
+    const background = new Graphics();
+    // Its own style object, never `textStyle('body')`: those are shared across the whole editor,
+    // so writing a family into one would restyle every label in the window.
+    const sample = new Text({ style: new TextStyle({ fontSize: SAMPLE_SIZE, fill: Theme.colors.text }) });
+    const caption = new Text({ style: textStyle('small') });
+    box.addChild(background, sample, caption);
+    return { box, background, sample, caption };
   }
 
-  get selected(): PickerItem | null {
-    return this.items.find((item) => item.file === this.selectedFile) ?? null;
-  }
+  protected redrawRow(row: FontRow, item: FontItem, selected: boolean): void {
+    this.drawBox(row, this.w, ROW_HEIGHT, selected);
+    // Empty family = not loaded yet; the row then reads in the editor's own typeface and the
+    // library's change event brings it back here once the face has arrived.
+    row.sample.style.fontFamily = fontLibrary.family(item.file) || Theme.font;
+    row.sample.text = truncate(SAMPLE_TEXT, row.sample.style, this.w - ROW_PAD * 2);
+    row.sample.position.set(ROW_PAD, ROW_PAD - 2);
 
-  get fileList(): string[] {
-    return this.items.map((item) => item.file);
-  }
-
-  get usedFiles(): string[] {
-    return this.items.filter((item) => item.assetName !== null).map((item) => item.file);
-  }
-
-  /** The captions as drawn, read off the rows themselves rather than recomputed (test hook). */
-  get captions(): string[] {
-    return this.rows.map((row) => row.caption.text);
-  }
-
-  select(file: string | null): void {
-    if (file === this.selectedFile) return;
-    this.selectedFile = file;
-    this.redraw();
-    if (file) this.onPick?.(file);
-  }
-
-  /** Global centre of a row; null when the file is not offered (test hook). */
-  rowGlobal(file: string): { x: number; y: number } | null {
-    const index = this.items.findIndex((item) => item.file === file);
-    const row = this.rows[index];
-    if (!row) return null;
-    const p = row.box.getGlobalPosition();
-    return { x: p.x + this.w / 2, y: p.y + ROW_HEIGHT / 2 };
-  }
-
-  override measure(): Size {
-    return { w: this.minWidth, h: Math.max(this.minHeight, heightFor(this.items.length)) };
-  }
-
-  override layout(): void {
-    this.rows.forEach((row, index) => row.box.position.set(0, index * (ROW_HEIGHT + ROW_GAP)));
-  }
-
-  override redraw(): void {
-    this.empty.text = this.items.length === 0 ? this.emptyText : '';
-    this.empty.position.set(0, 0);
-
-    this.rows.forEach((node, index) => {
-      const item = this.items[index];
-      if (!item) return;
-      const selected = item.file === this.selectedFile;
-      node.background.clear();
-      drawControlBox(node.background, this.w, ROW_HEIGHT, {
-        fill: selected ? Theme.colors.selection : Theme.colors.control,
-        border: selected ? Theme.colors.accent : Theme.colors.border,
-      });
-
-      // Empty family = not loaded yet; the row then reads in the editor's own typeface and the
-      // library's change event brings it back here once the face has arrived.
-      node.sample.style.fontFamily = fontLibrary.family(item.file) || Theme.font;
-      node.sample.text = truncate(SAMPLE_TEXT, node.sample.style, this.w - ROW_PAD * 2);
-      node.sample.position.set(ROW_PAD, ROW_PAD - 2);
-
-      // The asset name wins where there is one – it is what the project calls this face. Otherwise
-      // the name it was uploaded under, which is all a bare hash leaves to go on.
-      node.caption.style = textStyle(item.assetName ? 'accent' : 'muted');
-      node.caption.text = truncate(
-        item.assetName ?? (item.name || formatBytes(item.bytes)),
-        node.caption.style,
-        this.w - ROW_PAD * 2,
-      );
-      node.caption.position.set(ROW_PAD, ROW_HEIGHT - 16);
-    });
-  }
-
-  override destroy(): void {
-    this.stopWatching();
-    super.destroy({ children: true });
-  }
-
-  private onPress(e: FederatedPointerEvent): void {
-    const local = this.toLocal(e.global);
-    const index = Math.floor(local.y / (ROW_HEIGHT + ROW_GAP));
-    const item = local.x >= 0 && local.x <= this.w ? this.items[index] : undefined;
-    if (!item) return;
-    this.select(item.file);
-    if (pressCount(e, item.file) === 2) this.onActivate?.(item.file);
+    // The asset name wins where there is one – it is what the project calls this face. Otherwise
+    // the name it was uploaded under, which is all a bare hash leaves to go on.
+    row.caption.style = textStyle(item.assetName ? 'accent' : 'muted');
+    row.caption.text = truncate(
+      item.assetName ?? (item.name || formatBytes(item.bytes)),
+      row.caption.style,
+      this.w - ROW_PAD * 2,
+    );
+    row.caption.position.set(ROW_PAD, ROW_HEIGHT - 16);
   }
 }
 
-function heightFor(count: number): number {
-  return count === 0 ? 0 : count * ROW_HEIGHT + (count - 1) * ROW_GAP;
-}
-
-/**
- * Offers every typeface the server holds, the way the image picker offers pictures: uploading the
- * same font twice is wasteful, and nothing collects the files a project stopped referencing.
- */
-export class FontPicker extends Popup {
-  private readonly list = new FontList();
-  private readonly scroll = new ScrollContainer();
-  private readonly status: Label;
-  private readonly detail: Label;
-  private readonly use: Button;
+export class FontPicker extends FilePicker<FontItem> {
+  declare protected readonly list: FontList;
 
   constructor(private readonly deps: FontImportDeps) {
-    super({ modal: true, padding: Theme.padding * 2, gap: Theme.gap });
-    this.content.add(new Label('Choose a font', { style: 'bodyBold' }));
-    this.status = new Label('Loading fonts…', { style: 'muted' });
-    this.content.add(this.status);
-
-    this.list.minWidth = LIST_WIDTH;
-    this.list.emptyText = 'No fonts on the server yet – upload one.';
-    this.list.onPick = () => this.refreshSelection();
-    this.list.onActivate = () => this.confirm();
-    this.scroll.minWidth = LIST_WIDTH;
-    this.scroll.minHeight = LIST_HEIGHT;
-    this.scroll.setContent(this.list);
-    this.content.add(this.scroll);
-
-    this.detail = new Label('', { style: 'muted' });
-    this.content.add(this.detail);
-
-    const buttons = new HStack({ gap: Theme.gap, align: 'center' });
-    const upload = new Button('Upload…');
-    upload.onClick = this.closeThen(() => pickAndImportFonts(this.deps));
-    buttons.add(upload);
-    buttons.add(new Spacer(), 1);
-    const cancel = new Button('Cancel');
-    cancel.onClick = this.closeThen();
-    buttons.add(cancel);
-    this.use = new Button('Use font', { variant: 'primary' });
-    this.use.onClick = () => this.confirm();
-    this.use.setEnabled(false);
-    buttons.add(this.use);
-    this.content.add(buttons);
-
-    void this.loadList();
-  }
-
-  /** What the dialog offers, which of it the project already wears, and what is picked (test hook). */
-  debugInfo(): { files: string[]; used: string[]; captions: string[]; selected: string | null } {
-    return {
-      files: this.list.fileList,
-      used: this.list.usedFiles,
-      captions: this.list.captions,
-      selected: this.list.selected?.file ?? null,
-    };
+    super(
+      new FontList(),
+      {
+        title: 'Choose a font',
+        loading: 'Loading fonts…',
+        empty: 'No fonts on the server yet – upload one.',
+        use: 'Use font',
+        noun: 'font',
+      },
+      () => pickAndImportFonts(deps),
+    );
   }
 
   rowGlobal(file: string): { x: number; y: number } | null {
     return this.list.rowGlobal(file);
   }
 
-  override close(): void {
-    super.close();
-    if (current === this) current = null;
-    // Escape, Cancel and a confirmed pick all land here, and `Popup.close` tolerates a second
-    // call; the list's listener must be dropped exactly once.
-    if (!this.list.destroyed) this.list.destroy();
+  protected async fetchItems(): Promise<FontItem[]> {
+    return withAssetNames(await this.deps.fonts.list(), this.deps.state.project, 'font');
   }
 
-  private async loadList(): Promise<void> {
-    try {
-      const stored = await this.deps.fonts.list();
-      const named = new Map<string, string>();
-      for (const asset of this.deps.state.project.assets) {
-        if (asset.type === 'font') named.set(asset.file, asset.name);
-      }
-      this.list.setItems(stored.map((item) => ({ ...item, assetName: named.get(item.file) ?? null })));
-      this.scroll.minHeight = Math.min(
-        this.roomFor(this.scroll, ROW_HEIGHT),
-        Math.max(ROW_HEIGHT, heightFor(stored.length)),
-      );
-      this.status.setText(
-        stored.length === 1 ? '1 font on the server' : `${stored.length} fonts on the server`,
-      );
-    } catch (error) {
-      this.status.setText(
-        `Could not list the fonts: ${error instanceof Error ? error.message : String(error)}`,
-      );
-    }
-    this.refreshSelection();
+  protected contentHeight(count: number): { unit: number; total: number } {
+    return { unit: ROW_HEIGHT, total: this.list.heightFor(count) };
   }
 
-  private refreshSelection(): void {
-    const item = this.list.selected;
-    this.use.setEnabled(item !== null);
-    this.detail.setText(item ? describe(item) : '');
-    this.refreshLayout();
-  }
-
-  private confirm(): void {
-    const item = this.list.selected;
-    if (!item) return;
-    this.close();
+  protected adopt(item: FontItem): void {
     importStoredFont(item, this.deps);
   }
 }
 
-function describe(item: PickerItem): string {
-  const size = item.name ? `${item.name} – ${formatBytes(item.bytes)}` : formatBytes(item.bytes);
-  return item.assetName ? `${size} – already in the project as "${item.assetName}"` : size;
-}
-
-let current: FontPicker | null = null;
-
 export function openFontPicker(deps: FontImportDeps): FontPicker {
-  current?.close();
-  current = new FontPicker(deps);
-  current.openCentered();
-  return current;
+  return openPicker(new FontPicker(deps));
 }
 
-/** The open dialog, for the test hook. */
 export function currentFontPicker(): FontPicker | null {
-  return current;
+  return currentPicker(FontPicker);
 }

src/editor/fontImport.ts

@@ -1,9 +1,7 @@
 import { CreateFontCommand } from '../core/commands/assetCommands';
-import { nextAssetName } from '../core/commands/naming';
-import type { FontAsset } from '../core/model/Asset';
 import type { FontStore, UploadedFont } from '../core/store/FontStore';
+import { type ImportKind, type ImportOutcome, importFiles, importStored, pickAndImport } from './assetImport';
 import type { EditorState } from './state';
-import { type ImportOutcome, assetNameForFile, importNotice } from './textureImport';
 
 /** What the file dialog offers and a drop accepts; the server rejects everything else anyway. */
 export const FONT_ACCEPT = '.ttf,.otf,.woff,.woff2';
@@ -23,84 +21,27 @@ export interface FontImportDeps {
   fonts: FontStore;
 }
 
-/** Sequential like `importImages`, so each asset is named against the project as it then stands. */
-export async function importFonts(files: readonly File[], deps: FontImportDeps): Promise<ImportOutcome[]> {
-  if (files.length === 0) return [];
-  const outcomes: ImportOutcome[] = [];
-  for (const file of files) outcomes.push(await importFont(file, deps));
-  const created = outcomes.filter((outcome) => outcome.assetId !== null);
-  const last = created[created.length - 1];
-  if (last?.assetId) deps.state.select({ kind: 'asset', assetId: last.assetId });
-  deps.state.setNotice(importNotice(outcomes, 'font'));
-  return outcomes;
+const FONT_KIND: ImportKind<UploadedFont, FontImportDeps> = {
+  type: 'font',
+  noun: 'font',
+  fallbackName: 'Font',
+  store: (deps) => deps.fonts,
+  // The bytes go up untouched: unlike a picture, a typeface cannot be re-encoded smaller here.
+  prepare: (file) =>
+    isFontFileName(file.name)
+      ? Promise.resolve({ blob: file, type: file.type || 'application/octet-stream' })
+      : Promise.reject(new Error('Not a font file – use TTF, OTF, WOFF or WOFF2.')),
+  create: (name, font) => new CreateFontCommand(name, font.file),
+};
+
+export function importFonts(files: readonly File[], deps: FontImportDeps): Promise<ImportOutcome[]> {
+  return importFiles(FONT_KIND, files, deps);
 }
 
-async function importFont(file: File, deps: FontImportDeps): Promise<ImportOutcome> {
-  try {
-    if (!isFontFileName(file.name)) throw new Error('Not a font file – use TTF, OTF, WOFF or WOFF2.');
-    // The bytes go up untouched: unlike a picture, a typeface cannot be re-encoded smaller here.
-    const uploaded = await deps.fonts.upload(file, file.type || 'application/octet-stream', file.name);
-    return adopt(uploaded, assetNameForFile(file.name, 'Font'), file.name, deps);
-  } catch (error) {
-    return {
-      name: file.name,
-      assetId: null,
-      error: error instanceof Error ? error.message : String(error),
-    };
-  }
-}
-
-/** Makes an asset for a typeface the server holds, or reuses the one already naming those bytes. */
-function adopt(font: UploadedFont, nameBase: string, label: string, deps: FontImportDeps): ImportOutcome {
-  const existing = deps.state.project.assets.find(
-    (asset): asset is FontAsset => asset.type === 'font' && asset.file === font.file,
-  );
-  if (existing) return { name: label, assetId: existing.id, error: null, reused: true };
-
-  const name = nextAssetName(deps.state.project, nameBase);
-  const command = new CreateFontCommand(name, font.file);
-  // A rejected command has already put its reason into the notice; that is the message here.
-  if (!deps.state.execute(command)) return { name: label, assetId: null, error: deps.state.notice };
-  return { name: label, assetId: command.asset.id, error: null, reused: false };
-}
-
-/**
- * Adopts a typeface the server already holds – no upload, the bytes are there. Chosen in the
- * picker, so this is "+ → Font" and the asset is selected the way a created one would be.
- */
 export function importStoredFont(font: UploadedFont, deps: FontImportDeps): ImportOutcome {
-  // Named after the file it was uploaded as, like a dropped one; "Font" when the server knows none.
-  const outcome = adopt(font, assetNameForFile(font.name, 'Font'), font.name || font.file, deps);
-  if (outcome.assetId) deps.state.select({ kind: 'asset', assetId: outcome.assetId });
-  deps.state.setNotice(
-    outcome.error ??
-      (outcome.reused ? 'That font is already in the project.' : 'Added the font to the project.'),
-  );
-  return outcome;
-}
-
-/** Opens the browser's file dialog; resolves empty when the dialog was cancelled. */
-export function pickFontFiles(): Promise<File[]> {
-  return new Promise((resolve) => {
-    const input = document.createElement('input');
-    input.type = 'file';
-    input.accept = FONT_ACCEPT;
-    input.multiple = true;
-    input.style.display = 'none';
-    document.body.appendChild(input);
-    const finish = (files: File[]) => {
-      input.remove();
-      resolve(files);
-    };
-    input.addEventListener('change', () => finish([...(input.files ?? [])]));
-    // Without `cancel` a dismissed dialog leaves both the element and this promise behind.
-    input.addEventListener('cancel', () => finish([]));
-    input.click();
-  });
+  return importStored(FONT_KIND, font, deps);
 }
 
 export function pickAndImportFonts(deps: FontImportDeps): void {
-  void pickFontFiles()
-    .then((files) => importFonts(files, deps))
-    .catch((error: unknown) => deps.state.setNotice(String(error), 'error'));
+  pickAndImport(FONT_KIND, FONT_ACCEPT, deps);
 }

src/editor/graph/GraphCanvas.ts

@@ -2,19 +2,13 @@ import { Container, type FederatedPointerEvent, type FederatedWheelEvent, Graphi
 import { textOf } from '../../core/model/Properties';
 import type { Command } from '../../core/commands/Command';
 import { oneStep } from '../../core/commands/CompoundCommand';
-import {
-  AddNodeCommand,
-  CollapseNodesCommand,
-  ConnectCommand,
-  MoveNodeCommand,
-} from '../../core/commands/graphCommands';
+import { AddNodeCommand, CollapseNodesCommand, ConnectCommand } from '../../core/commands/graphCommands';
 import { SetMachineStartCommand } from '../../core/commands/assetCommands';
 import {
   AddAnnotationCommand,
   type AnnotationBox,
   annotationNoun,
   normalizeBox,
-  SetAnnotationBoxCommand,
 } from '../../core/commands/annotationCommands';
 import {
   type AnnotationKind,
@@ -32,7 +26,6 @@ import {
   firstPortFor,
   ghostProblem,
   type Graph,
-  type GraphAnnotation,
   type GraphNode,
   type GraphLookup,
   MIN_ANNOTATION_SIZE,
@@ -75,13 +68,22 @@ import { annotationSelection, type EditorState, graphSelection, nodeSelection }
 import {
   type Box,
   boundsOf,
-  boxesCentredIn,
   boxesInBand,
   boxesWithinBand,
   dragOffset,
   frameBoxes,
   resizeSize,
 } from '../framing';
+import {
+  annotationBoxes,
+  boxOf,
+  type BoxSeed,
+  boxSeeds,
+  placeTravellers,
+  recordTravellers,
+  travellers,
+  type Travellers,
+} from './annotationDrag';
 import { ANNOTATION_TITLE_HEIGHT, AnnotationView, RESIZE_HANDLE } from './AnnotationView';
 import { arrowHead, bezier, EdgeLayer } from './EdgeLayer';
 import { arrowShaft, type Point, transitionPreview } from './transitions';
@@ -141,25 +143,17 @@ export class GraphCanvas extends Widget {
   private pan = { x: 0, y: 0 };
   private zoom = 1;
   private panning: { startX: number; startY: number; panX: number; panY: number } | null = null;
-  private dragging: {
-    items: { nodeId: string; start: { x: number; y: number } }[];
-    /** Boxes selected alongside the nodes: a band caught them together, so they travel together. */
-    boxes: { id: string; kind: AnnotationKind; start: AnnotationBox }[];
-    pointer: { x: number; y: number };
-    moved: boolean;
-  } | null = null;
+  /** Nodes being dragged, with the boxes a band caught alongside them – they travel together. */
+  private dragging: { along: Travellers; pointer: { x: number; y: number }; moved: boolean } | null = null;
   /**
-   * A group or comment being moved or resized. `members` is fixed when the drag begins: which
-   * nodes a group carries is a question about where they were when it was grabbed, not a running
-   * one – otherwise a node would join the group halfway through the gesture that passes over it.
+   * A group or comment being moved or resized. `along` is fixed when the drag begins: which nodes a
+   * group carries is a question about where they were when it was grabbed, not a running one –
+   * otherwise a node would join the group halfway through the gesture that passes over it.
    */
   private annotationDrag: {
-    id: string;
-    kind: AnnotationKind;
+    grabbed: BoxSeed;
     mode: 'move' | 'resize';
-    start: AnnotationBox;
-    members: { nodeId: string; start: { x: number; y: number } }[];
-    nested: { id: string; kind: AnnotationKind; start: AnnotationBox }[];
+    along: Travellers;
     pointer: { x: number; y: number };
     moved: boolean;
   } | null = null;
@@ -380,106 +374,27 @@ export class GraphCanvas extends Widget {
       return;
     }
     if (e.button !== 0) return;
+    const graph = this.asset()?.graph;
+    if (!graph) return;
     const local = view.toLocal(e.global);
     const p = this.toLocal(e.global);
-    const pointer = this.screenToGraph(p.x, p.y);
-    const start = boxOf(view.annotation);
+    const grabbed: BoxSeed = { id, kind: view.kind, start: boxOf(view.annotation) };
     const resizing = view.handleAt(local.x, local.y);
     // A resize carries nothing: membership is re-derived from where the box ends up, so a node the
     // corner sweeps over simply belongs to it after.
+    const seeds = [grabbed, ...boxSeeds(graph, this.state.selectedAnnotationIds, id)];
     const along = resizing
-      ? { boxes: [], nodes: [] }
-      : this.travellers(
-          [{ id, kind: view.kind, start }, ...this.selectedBoxes(id)],
-          this.state.selectedNodeIds,
-        );
+      ? { boxes: [grabbed], nodes: [] }
+      : travellers(graph, this.nodeBoxes(), seeds, this.state.selectedNodeIds);
     this.annotationDrag = {
-      id,
-      kind: view.kind,
+      grabbed,
       mode: resizing ? 'resize' : 'move',
-      start,
-      members: along.nodes,
-      nested: along.boxes.filter((b) => b.id !== id),
-      pointer,
+      along,
+      pointer: this.screenToGraph(p.x, p.y),
       moved: false,
     };
   }
 
-  /** The selected groups and comments as drag seeds, `exceptId` left out (it is the grabbed one). */
-  private selectedBoxes(exceptId?: string): { id: string; kind: AnnotationKind; start: AnnotationBox }[] {
-    const graph = this.asset()?.graph;
-    if (!graph) return [];
-    const seeds: { id: string; kind: AnnotationKind; start: AnnotationBox }[] = [];
-    for (const selected of this.state.selectedAnnotationIds) {
-      if (selected === exceptId) continue;
-      const found = findAnnotation(graph, selected);
-      if (found) seeds.push({ id: selected, kind: found.kind, start: boxOf(found.annotation) });
-    }
-    return seeds;
-  }
-
-  /**
-   * Everything one move gesture carries: the boxes it starts from, the boxes those hold, and every
-   * node beneath any of them – each node exactly once, however many groups claim it. Without that
-   * last part a node inside a group that is itself selected would be offset twice.
-   */
-  private travellers(
-    seedBoxes: readonly { id: string; kind: AnnotationKind; start: AnnotationBox }[],
-    seedNodeIds: readonly string[],
-  ): {
-    boxes: { id: string; kind: AnnotationKind; start: AnnotationBox }[];
-    nodes: { nodeId: string; start: { x: number; y: number } }[];
-  } {
-    const boxes = new Map(seedBoxes.map((b) => [b.id, b]));
-    for (const seed of seedBoxes) {
-      if (seed.kind !== 'group') continue;
-      for (const nested of this.nestedMembers(seed.id, seed.start))
-        if (!boxes.has(nested.id)) boxes.set(nested.id, nested);
-    }
-    const nodes = new Map<string, { nodeId: string; start: { x: number; y: number } }>();
-    const graph = this.asset()?.graph;
-    for (const id of seedNodeIds) {
-      const node = graph?.nodes.find((n) => n.id === id);
-      if (node) nodes.set(id, { nodeId: id, start: { x: node.x, y: node.y } });
-    }
-    for (const box of boxes.values()) {
-      if (box.kind !== 'group') continue;
-      for (const member of this.nodeMembers(box.start))
-        if (!nodes.has(member.nodeId)) nodes.set(member.nodeId, member);
-    }
-    return { boxes: [...boxes.values()], nodes: [...nodes.values()] };
-  }
-
-  /** The nodes a group at this box carries – the centre rule, against what is drawn right now. */
-  private nodeMembers(box: AnnotationBox): { nodeId: string; start: { x: number; y: number } }[] {
-    const graph = this.asset()?.graph;
-    const ids = new Set(boxesCentredIn(this.nodeBoxes(), box));
-    return (graph?.nodes ?? [])
-      .filter((n) => ids.has(n.id))
-      .map((n) => ({ nodeId: n.id, start: { x: n.x, y: n.y } }));
-  }
-
-  /** Groups and comments inside a group: the outer one takes them, and with them their own nodes. */
-  private nestedMembers(
-    selfId: string,
-    box: AnnotationBox,
-  ): { id: string; kind: AnnotationKind; start: AnnotationBox }[] {
-    const graph = this.asset()?.graph;
-    if (!graph) return [];
-    const inside: { id: string; kind: AnnotationKind; start: AnnotationBox }[] = [];
-    for (const kind of ANNOTATION_KINDS) {
-      const list = annotationsOf(graph, kind).filter((a) => a.id !== selfId);
-      const ids = new Set(
-        boxesCentredIn(
-          list.map((a) => ({ id: a.id, ...boxOf(a) })),
-          box,
-        ),
-      );
-      for (const a of list) if (ids.has(a.id)) inside.push({ id: a.id, kind, start: boxOf(a) });
-    }
-    return inside;
-  }
-
   /** Moves or resizes the dragged box in the model, for the preview; committed on release. */
   private previewAnnotationDrag(g: { x: number; y: number }): void {
     const drag = this.annotationDrag;
@@ -489,29 +404,16 @@ export class GraphCanvas extends Widget {
     const dy = g.y - drag.pointer.y;
     if (!drag.moved && Math.hypot(dx, dy) * this.zoom < DRAG_THRESHOLD) return;
     drag.moved = true;
-    const self = findAnnotation(graph, drag.id)?.annotation;
-    if (!self) return;
     const step = this.snapping ? GRID_STEP : 0;
     if (drag.mode === 'resize') {
-      const size = resizeSize(drag.start, dx, dy, step, MIN_ANNOTATION_SIZE);
-      Object.assign(self, normalizeBox({ ...drag.start, ...size }));
-      this.state.preview();
-      return;
-    }
-    const offset = dragOffset(drag.start, dx, dy, step);
-    self.x = drag.start.x + offset.x;
-    self.y = drag.start.y + offset.y;
-    for (const member of drag.members) {
-      const node = graph.nodes.find((n) => n.id === member.nodeId);
-      if (!node) continue;
-      node.x = member.start.x + offset.x;
-      node.y = member.start.y + offset.y;
-    }
-    for (const member of drag.nested) {
-      const nested = findAnnotation(graph, member.id)?.annotation;
-      if (!nested) continue;
-      nested.x = member.start.x + offset.x;
-      nested.y = member.start.y + offset.y;
+      const self = findAnnotation(graph, drag.grabbed.id)?.annotation;
+      if (!self) return;
+      const size = resizeSize(drag.grabbed.start, dx, dy, step, MIN_ANNOTATION_SIZE);
+      Object.assign(self, normalizeBox({ ...drag.grabbed.start, ...size }));
+    } else {
+      // One offset for all of it, the grabbed box's: what travels with a group keeps its distance.
+      const offset = dragOffset(drag.grabbed.start, dx, dy, step);
+      placeTravellers(graph, drag.along, () => offset);
     }
     this.state.preview();
   }
@@ -522,30 +424,10 @@ export class GraphCanvas extends Widget {
     this.annotationDrag = null;
     const graph = this.asset()?.graph;
     if (!drag?.moved || !graph || !this.assetId) return;
-    const self = findAnnotation(graph, drag.id)?.annotation;
-    if (!self) return;
-    const commands: Command[] = [];
-    const take = (a: GraphAnnotation, kind: AnnotationKind, id: string, start: AnnotationBox) => {
-      const next = boxOf(a);
-      Object.assign(a, start);
-      commands.push(new SetAnnotationBoxCommand(this.assetId, kind, id, next, label));
-    };
-    const label = drag.mode === 'resize' ? `Resize ${annotationNoun(drag.kind)}` : undefined;
-    take(self, drag.kind, drag.id, drag.start);
-    for (const member of drag.nested) {
-      const nested = findAnnotation(graph, member.id)?.annotation;
-      if (nested) take(nested, member.kind, member.id, member.start);
-    }
-    for (const member of drag.members) {
-      const node = graph.nodes.find((n) => n.id === member.nodeId);
-      if (!node) continue;
-      const next = { x: node.x, y: node.y };
-      node.x = member.start.x;
-      node.y = member.start.y;
-      commands.push(new MoveNodeCommand(this.assetId, member.nodeId, next.x, next.y));
-    }
-    const verb = drag.mode === 'resize' ? 'Resize' : 'Move';
-    this.state.execute(oneStep(`${verb} ${annotationNoun(drag.kind)}`, commands));
+    const noun = annotationNoun(drag.grabbed.kind);
+    const label = drag.mode === 'resize' ? `Resize ${noun}` : undefined;
+    const commands = recordTravellers(graph, this.assetId, drag.along, label);
+    this.state.execute(oneStep(`${drag.mode === 'resize' ? 'Resize' : 'Move'} ${noun}`, commands));
   }
 
   /** Adds a group or comment and selects it, so its title can be typed straight away. */
@@ -625,7 +507,7 @@ export class GraphCanvas extends Widget {
     const asset = this.asset();
     // Groups and comments are part of the picture: a fit that framed only the nodes would cut the
     // box drawn around them, and a graph holding nothing but a comment would frame the origin.
-    const boxes = asset ? [...this.nodeBoxes(), ...this.annotationBoxes()] : [];
+    const boxes = asset ? [...this.nodeBoxes(), ...annotationBoxes(asset.graph)] : [];
     if (boxes.length === 0) {
       this.pan = { x: this.w / 2 - NODE_WIDTH / 2, y: this.h / 3 };
       this.zoom = 1;
@@ -641,15 +523,6 @@ export class GraphCanvas extends Widget {
     this.applyView();
   }
 
-  /** Every group and comment as the rectangle it is drawn as – a box states its own size. */
-  private annotationBoxes(): Box[] {
-    const graph = this.asset()?.graph;
-    if (!graph) return [];
-    return ANNOTATION_KINDS.flatMap((kind) =>
-      annotationsOf(graph, kind).map((a) => ({ id: a.id, ...boxOf(a) })),
-    );
-  }
-
   /** Each node as the rectangle it is actually drawn as (a view knows its own height). */
   private nodeBoxes(): Box[] {
     return (this.asset()?.graph.nodes ?? []).map((node) => {
@@ -786,11 +659,12 @@ export class GraphCanvas extends Widget {
     // Clicking a selected node keeps the selection so the whole group can be dragged.
     if (!this.state.selectedNodeIds.includes(view.node.id))
       this.state.select(nodeSelection(this.assetId, [view.node.id]));
+    const graph = this.asset()?.graph;
+    if (!graph) return;
     const p = this.toLocal(e.global);
-    const along = this.travellers(this.selectedBoxes(), this.state.selectedNodeIds);
+    const seeds = boxSeeds(graph, this.state.selectedAnnotationIds);
     this.dragging = {
-      items: along.nodes,
-      boxes: along.boxes,
+      along: travellers(graph, this.nodeBoxes(), seeds, this.state.selectedNodeIds),
       pointer: this.screenToGraph(p.x, p.y),
       moved: false,
     };
@@ -837,21 +711,8 @@ export class GraphCanvas extends Widget {
       const graph = this.asset()?.graph;
       if (!graph) return;
       const step = this.snapping ? GRID_STEP : 0;
-      for (const item of this.dragging.items) {
-        const node = graph.nodes.find((n) => n.id === item.nodeId);
-        if (!node) continue;
-        const offset = dragOffset(item.start, dx, dy, step);
-        node.x = item.start.x + offset.x;
-        node.y = item.start.y + offset.y;
-      }
-      // Boxes caught by the same band travel with the nodes, each snapping for itself as a node does.
-      for (const box of this.dragging.boxes) {
-        const found = findAnnotation(graph, box.id)?.annotation;
-        if (!found) continue;
-        const offset = dragOffset(box.start, dx, dy, step);
-        found.x = box.start.x + offset.x;
-        found.y = box.start.y + offset.y;
-      }
+      // Each thing snaps for itself, node or box, so what lands on the grid is what was grabbed.
+      placeTravellers(graph, this.dragging.along, (start) => dragOffset(start, dx, dy, step));
       this.state.preview();
     } else if (this.connecting) {
       this.connecting.pointer = g;
@@ -928,26 +789,10 @@ export class GraphCanvas extends Widget {
     }
     const drag = this.dragging;
     this.dragging = null;
-    if (drag?.moved && this.assetId) {
-      const graph = this.asset()?.graph;
-      const moves: Command[] = [];
-      for (const item of drag.items) {
-        const node = graph?.nodes.find((n) => n.id === item.nodeId);
-        if (!node) continue;
-        // The preview moved the node already; put it back so the command records the start.
-        const next = { x: node.x, y: node.y };
-        node.x = item.start.x;
-        node.y = item.start.y;
-        moves.push(new MoveNodeCommand(this.assetId, item.nodeId, next.x, next.y));
-      }
+    const graph = this.asset()?.graph;
+    if (drag?.moved && graph && this.assetId) {
       // The boxes that came along belong in the same step: one gesture, one undo.
-      for (const box of drag.boxes) {
-        const found = graph && findAnnotation(graph, box.id)?.annotation;
-        if (!found) continue;
-        const next = boxOf(found);
-        Object.assign(found, box.start);
-        moves.push(new SetAnnotationBoxCommand(this.assetId, box.kind, box.id, next));
-      }
+      const moves = recordTravellers(graph, this.assetId, drag.along);
       if (moves.length > 0) this.state.execute(oneStep('Move nodes', moves));
     }
     const connecting = this.connecting;
@@ -975,7 +820,8 @@ export class GraphCanvas extends Widget {
     };
     const ids = boxesInBand(this.nodeBoxes(), band);
     // A box counts only when the band holds all of it – see `boxesWithinBand`.
-    const boxIds = boxesWithinBand(this.annotationBoxes(), band);
+    const graph = this.asset()?.graph;
+    const boxIds = graph ? boxesWithinBand(annotationBoxes(graph), band) : [];
     // An empty band clears the selection but keeps the behavior, as a plain click does.
     this.state.select(graphSelection(this.assetId, ids, boxIds) ?? { kind: 'asset', assetId: this.assetId });
   }
@@ -1512,10 +1358,6 @@ function globalRect(target: Container, w: number, h: number): Rect {
   return { x: topLeft.x, y: topLeft.y, w: bottomRight.x - topLeft.x, h: bottomRight.y - topLeft.y };
 }
 
-function boxOf(annotation: GraphAnnotation): AnnotationBox {
-  return { x: annotation.x, y: annotation.y, w: annotation.w, h: annotation.h };
-}
-
 /** A drag may start at either end; the command wants the output first. */
 function connectSides(assetId: string, a: PortSide, b: PortSide): ConnectCommand {
   const [out, inp] = a.isOutput ? [a, b] : [b, a];

src/editor/graph/annotationDrag.ts

@@ -0,0 +1,161 @@
+/**
+ * What a drag in the graph carries and how it is written back. A group takes the nodes whose centre
+ * lies in it and the boxes inside it, a band may have caught nodes and boxes together, and either
+ * way a thing must move exactly once – a node inside a selected group is claimed twice and offset
+ * once. Pure over the graph and the drawn node boxes, so the rule is testable without a canvas.
+ */
+import { type AnnotationBox, SetAnnotationBoxCommand } from '../../core/commands/annotationCommands';
+import type { Command } from '../../core/commands/Command';
+import { MoveNodeCommand } from '../../core/commands/graphCommands';
+import {
+  type AnnotationKind,
+  ANNOTATION_KINDS,
+  annotationsOf,
+  findAnnotation,
+  type Graph,
+  type GraphAnnotation,
+} from '../../core/graph';
+import { type Box, boxesCentredIn, type Point } from '../framing';
+
+/** A box as the drag found it. */
+export interface BoxSeed {
+  id: string;
+  kind: AnnotationKind;
+  start: AnnotationBox;
+}
+
+/** A node as the drag found it. */
+export interface NodeSeed {
+  nodeId: string;
+  start: Point;
+}
+
+export interface Travellers {
+  boxes: BoxSeed[];
+  nodes: NodeSeed[];
+}
+
+export function boxOf(annotation: GraphAnnotation): AnnotationBox {
+  return { x: annotation.x, y: annotation.y, w: annotation.w, h: annotation.h };
+}
+
+/** Every group and comment as the rectangle it is drawn as – a box states its own size. */
+export function annotationBoxes(graph: Graph): Box[] {
+  return ANNOTATION_KINDS.flatMap((kind) =>
+    annotationsOf(graph, kind).map((a) => ({ id: a.id, ...boxOf(a) })),
+  );
+}
+
+/** The boxes with these ids as drag seeds, `exceptId` left out (it is the grabbed one). */
+export function boxSeeds(graph: Graph, ids: readonly string[], exceptId?: string): BoxSeed[] {
+  const seeds: BoxSeed[] = [];
+  for (const id of ids) {
+    if (id === exceptId) continue;
+    const found = findAnnotation(graph, id);
+    if (found) seeds.push({ id, kind: found.kind, start: boxOf(found.annotation) });
+  }
+  return seeds;
+}
+
+/**
+ * Everything one move gesture carries: the boxes it starts from, the boxes those hold, and every
+ * node beneath any of them – each node exactly once, however many groups claim it. `nodeBoxes`
+ * are the nodes as drawn, since a node's height is the view's to know.
+ */
+export function travellers(
+  graph: Graph,
+  nodeBoxes: readonly Box[],
+  seedBoxes: readonly BoxSeed[],
+  seedNodeIds: readonly string[],
+): Travellers {
+  const boxes = new Map(seedBoxes.map((b) => [b.id, b]));
+  for (const seed of seedBoxes) {
+    if (seed.kind !== 'group') continue;
+    for (const nested of nestedMembers(graph, seed.id, seed.start))
+      if (!boxes.has(nested.id)) boxes.set(nested.id, nested);
+  }
+  const nodes = new Map<string, NodeSeed>();
+  for (const id of seedNodeIds) {
+    const node = graph.nodes.find((n) => n.id === id);
+    if (node) nodes.set(id, { nodeId: id, start: { x: node.x, y: node.y } });
+  }
+  for (const box of boxes.values()) {
+    if (box.kind !== 'group') continue;
+    for (const member of nodeMembers(graph, nodeBoxes, box.start))
+      if (!nodes.has(member.nodeId)) nodes.set(member.nodeId, member);
+  }
+  return { boxes: [...boxes.values()], nodes: [...nodes.values()] };
+}
+
+/** The nodes a group at this box carries – the centre rule, against what is drawn right now. */
+function nodeMembers(graph: Graph, nodeBoxes: readonly Box[], box: AnnotationBox): NodeSeed[] {
+  const ids = new Set(boxesCentredIn(nodeBoxes, box));
+  return graph.nodes.filter((n) => ids.has(n.id)).map((n) => ({ nodeId: n.id, start: { x: n.x, y: n.y } }));
+}
+
+/** Groups and comments inside a group: the outer one takes them, and with them their own nodes. */
+function nestedMembers(graph: Graph, selfId: string, box: AnnotationBox): BoxSeed[] {
+  const inside: BoxSeed[] = [];
+  for (const kind of ANNOTATION_KINDS) {
+    const list = annotationsOf(graph, kind).filter((a) => a.id !== selfId);
+    const ids = new Set(
+      boxesCentredIn(
+        list.map((a) => ({ id: a.id, ...boxOf(a) })),
+        box,
+      ),
+    );
+    for (const a of list) if (ids.has(a.id)) inside.push({ id: a.id, kind, start: boxOf(a) });
+  }
+  return inside;
+}
+
+/**
+ * Puts every traveller where the gesture has it now, for the preview. `offsetFor` answers per start
+ * position, because with snapping on each thing lands on the grid for itself, as a node does.
+ */
+export function placeTravellers(graph: Graph, along: Travellers, offsetFor: (start: Point) => Point): void {
+  for (const member of along.nodes) {
+    const node = graph.nodes.find((n) => n.id === member.nodeId);
+    if (!node) continue;
+    const offset = offsetFor(member.start);
+    node.x = member.start.x + offset.x;
+    node.y = member.start.y + offset.y;
+  }
+  for (const member of along.boxes) {
+    const box = findAnnotation(graph, member.id)?.annotation;
+    if (!box) continue;
+    const offset = offsetFor(member.start);
+    box.x = member.start.x + offset.x;
+    box.y = member.start.y + offset.y;
+  }
+}
+
+/**
+ * The commands that take everything from where the drag found it to where the preview left it.
+ * The preview has already moved the model; each thing is put back first so the command records the
+ * start, and the caller runs them as one step. `label` names a box command that is not a plain move.
+ */
+export function recordTravellers(
+  graph: Graph,
+  assetId: string,
+  along: Travellers,
+  label?: string,
+): Command[] {
+  const commands: Command[] = [];
+  for (const member of along.boxes) {
+    const box = findAnnotation(graph, member.id)?.annotation;
+    if (!box) continue;
+    const next = boxOf(box);
+    Object.assign(box, member.start);
+    commands.push(new SetAnnotationBoxCommand(assetId, member.kind, member.id, next, label));
+  }
+  for (const member of along.nodes) {
+    const node = graph.nodes.find((n) => n.id === member.nodeId);
+    if (!node) continue;
+    const next = { x: node.x, y: node.y };
+    node.x = member.start.x;
+    node.y = member.start.y;
+    commands.push(new MoveNodeCommand(assetId, member.nodeId, next.x, next.y));
+  }
+  return commands;
+}

src/editor/sound/SoundPicker.ts

@@ -1,247 +1,108 @@
 import { Container, type FederatedPointerEvent, Graphics, Text } from 'pixi.js';
 import type { StoredSound } from '../../core/store/SoundStore';
-import {
-  Button,
-  drawControlBox,
-  formatBytes,
-  HStack,
-  Label,
-  Popup,
-  pressCount,
-  ScrollContainer,
-  type Size,
-  Spacer,
-  Theme,
-  textStyle,
-  truncate,
-  Widget,
-} from '../../ui';
+import { formatBytes, textStyle, truncate } from '../../ui';
 import { soundLibrary } from '../../viewport/SoundLibrary';
+import {
+  currentPicker,
+  FilePicker,
+  openPicker,
+  type PickerItem,
+  type PickerRow,
+  RowList,
+  withAssetNames,
+} from '../FilePicker';
 import { type SoundImportDeps, importStoredSound, pickAndImportSounds } from '../soundImport';
 
-/** The dialog keeps this size whatever the list turns out to be, so it does not jump on opening. */
-const LIST_WIDTH = 560;
-const LIST_HEIGHT = 340;
 const ROW_HEIGHT = 44;
-const ROW_GAP = 4;
 const ROW_PAD = 8;
 /** The play glyph's column at the left of a row: a press in here plays instead of selecting. */
 const PLAY_WIDTH = 34;
+const IDLE_HINT = 'Press ▶ to hear one.';
 
-/** One offered sound, with the asset that already uses it (if any). */
-interface PickerItem extends StoredSound {
-  assetName: string | null;
+type SoundItem = PickerItem<StoredSound>;
+interface SoundRow extends PickerRow {
+  play: Text;
+  detail: Text;
 }
 
 /**
- * The rows. A sound has nothing to show, so each row shows what is known about the file and plays
- * it on demand: the ▶ at its left is the preview, the rest of the row is the pick.
+ * A sound has nothing to show, so each row shows what is known about the file and plays it on
+ * demand: the ▶ at its left is the preview, the rest of the row is the pick.
  */
-class SoundList extends Widget {
-  private items: PickerItem[] = [];
-  private rows: { box: Container; background: Graphics; play: Text; caption: Text; detail: Text }[] = [];
-  private selectedFile: string | null = null;
-  private readonly empty = new Text({ text: '', style: textStyle('muted') });
-  onPick?: (file: string) => void;
-  onActivate?: (file: string) => void;
-  emptyText = '';
+class SoundList extends RowList<SoundItem, SoundRow> {
+  protected readonly rowHeight = ROW_HEIGHT;
   /** The last file a ▶ started, so a check can tell a preview from a pick (test hook). */
   lastPlayed: string | null = null;
 
-  constructor() {
-    super();
-    this.addChild(this.empty);
-    this.on('pointerdown', (e: FederatedPointerEvent) => this.onPress(e));
-  }
-
-  setItems(items: PickerItem[]): void {
-    this.items = items;
-    for (const row of this.rows) row.box.destroy({ children: true });
-    this.rows = items.map(() => {
-      // A Container holding the background, not a Graphics with children: Pixi v8 only lets
-      // containers have them (`addChild: Only Containers will be allowed to add children`).
-      const box = new Container();
-      const background = new Graphics();
-      const play = new Text({ text: '▶', style: textStyle('accent') });
-      const caption = new Text({ style: textStyle('body') });
-      const detail = new Text({ style: textStyle('small') });
-      box.addChild(background, play, caption, detail);
-      this.addChild(box);
-      return { box, background, play, caption, detail };
-    });
-    if (!items.some((item) => item.file === this.selectedFile)) this.selectedFile = null;
-    this.layout();
-    this.redraw();
-  }
-
-  get selected(): PickerItem | null {
-    return this.items.find((item) => item.file === this.selectedFile) ?? null;
-  }
-
-  get fileList(): string[] {
-    return this.items.map((item) => item.file);
-  }
-
-  get usedFiles(): string[] {
-    return this.items.filter((item) => item.assetName !== null).map((item) => item.file);
-  }
-
-  /** The captions as drawn, read off the rows themselves rather than recomputed (test hook). */
-  get captions(): string[] {
-    return this.rows.map((row) => row.caption.text);
-  }
-
-  select(file: string | null): void {
-    if (file === this.selectedFile) return;
-    this.selectedFile = file;
-    this.redraw();
-    if (file) this.onPick?.(file);
-  }
-
-  /** Global centre of a row, clear of the ▶ column; null when the file is not offered (test hook). */
-  rowGlobal(file: string): { x: number; y: number } | null {
-    const index = this.items.findIndex((item) => item.file === file);
-    const row = this.rows[index];
-    if (!row) return null;
-    const p = row.box.getGlobalPosition();
-    return { x: p.x + PLAY_WIDTH + (this.w - PLAY_WIDTH) / 2, y: p.y + ROW_HEIGHT / 2 };
-  }
-
   /** Global centre of a row's ▶ – what a check presses to hear one without choosing it. */
   playGlobal(file: string): { x: number; y: number } | null {
-    const index = this.items.findIndex((item) => item.file === file);
-    const row = this.rows[index];
-    if (!row) return null;
-    const p = row.box.getGlobalPosition();
+    const found = this.rowOf(file);
+    if (!found) return null;
+    const p = found.row.box.getGlobalPosition();
     return { x: p.x + PLAY_WIDTH / 2, y: p.y + ROW_HEIGHT / 2 };
   }
 
-  override measure(): Size {
-    return { w: this.minWidth, h: Math.max(this.minHeight, heightFor(this.items.length)) };
+  protected buildRow(): SoundRow {
+    const box = new Container();
+    const background = new Graphics();
+    const play = new Text({ text: '▶', style: textStyle('accent') });
+    const caption = new Text({ style: textStyle('body') });
+    const detail = new Text({ style: textStyle('small') });
+    box.addChild(background, play, caption, detail);
+    return { box, background, play, caption, detail };
   }
 
-  override layout(): void {
-    this.rows.forEach((row, index) => row.box.position.set(0, index * (ROW_HEIGHT + ROW_GAP)));
+  protected redrawRow(row: SoundRow, item: SoundItem, selected: boolean): void {
+    this.drawBox(row, this.w, ROW_HEIGHT, selected);
+    row.play.position.set(ROW_PAD + 2, (ROW_HEIGHT - row.play.height) / 2);
+
+    const width = this.w - PLAY_WIDTH - ROW_PAD;
+    row.caption.style = textStyle(item.assetName ? 'accent' : 'body');
+    row.caption.text = truncate(item.assetName ?? item.name, row.caption.style, width);
+    row.caption.position.set(PLAY_WIDTH, 6);
+
+    const detail =
+      item.assetName && item.name ? `${item.name} – ${formatBytes(item.bytes)}` : formatBytes(item.bytes);
+    row.detail.text = truncate(detail, row.detail.style, width);
+    row.detail.position.set(PLAY_WIDTH, ROW_HEIGHT - 16);
   }
 
-  override redraw(): void {
-    this.empty.text = this.items.length === 0 ? this.emptyText : '';
-    this.empty.position.set(0, 0);
-
-    this.rows.forEach((node, index) => {
-      const item = this.items[index];
-      if (!item) return;
-      const selected = item.file === this.selectedFile;
-      node.background.clear();
-      drawControlBox(node.background, this.w, ROW_HEIGHT, {
-        fill: selected ? Theme.colors.selection : Theme.colors.control,
-        border: selected ? Theme.colors.accent : Theme.colors.border,
-      });
-      node.play.position.set(ROW_PAD + 2, (ROW_HEIGHT - node.play.height) / 2);
-
-      // The asset name wins where there is one – it is what the project calls this sound. Otherwise
-      // the name it was uploaded under, which is all a bare hash leaves to go on.
-      node.caption.style = textStyle(item.assetName ? 'accent' : 'body');
-      node.caption.text = truncate(
-        item.assetName ?? item.name,
-        node.caption.style,
-        this.w - PLAY_WIDTH - ROW_PAD,
-      );
-      node.caption.position.set(PLAY_WIDTH, 6);
-
-      node.detail.text = truncate(
-        item.assetName && item.name ? `${item.name} – ${formatBytes(item.bytes)}` : formatBytes(item.bytes),
-        node.detail.style,
-        this.w - PLAY_WIDTH - ROW_PAD,
-      );
-      node.detail.position.set(PLAY_WIDTH, ROW_HEIGHT - 16);
-    });
-  }
-
-  private onPress(e: FederatedPointerEvent): void {
+  protected override onPress(e: FederatedPointerEvent): void {
     const local = this.toLocal(e.global);
-    const index = Math.floor(local.y / (ROW_HEIGHT + ROW_GAP));
-    const item = local.x >= 0 && local.x <= this.w ? this.items[index] : undefined;
-    if (!item) return;
-    if (local.x < PLAY_WIDTH) {
+    const item = this.items[this.indexAt(local.x, local.y)];
+    if (item && local.x < PLAY_WIDTH) {
       this.lastPlayed = item.file;
       soundLibrary.play(item.file, 1, false);
       return;
     }
-    this.select(item.file);
-    if (pressCount(e, item.file) === 2) this.onActivate?.(item.file);
+    super.onPress(e);
   }
 }
 
-function heightFor(count: number): number {
-  return count === 0 ? 0 : count * ROW_HEIGHT + (count - 1) * ROW_GAP;
-}
-
-/**
- * Offers every sound the server holds, the way the font picker offers typefaces: uploading the same
- * file twice is wasteful, and nothing collects the files a project stopped referencing.
- */
-export class SoundPicker extends Popup {
-  private readonly list = new SoundList();
-  private readonly scroll = new ScrollContainer();
-  private readonly status: Label;
-  private readonly detail: Label;
-  private readonly use: Button;
+export class SoundPicker extends FilePicker<SoundItem> {
+  declare protected readonly list: SoundList;
 
   constructor(private readonly deps: SoundImportDeps) {
-    super({ modal: true, padding: Theme.padding * 2, gap: Theme.gap });
-    this.content.add(new Label('Choose a sound', { style: 'bodyBold' }));
-    this.status = new Label('Loading sounds…', { style: 'muted' });
-    this.content.add(this.status);
-
-    this.list.minWidth = LIST_WIDTH;
-    this.list.emptyText = 'No sounds on the server yet – upload one.';
-    this.list.onPick = () => this.refreshSelection();
-    this.list.onActivate = () => this.confirm();
-    this.scroll.minWidth = LIST_WIDTH;
-    this.scroll.minHeight = LIST_HEIGHT;
-    this.scroll.setContent(this.list);
-    this.content.add(this.scroll);
-
-    this.detail = new Label('Press ▶ to hear one.', { style: 'muted' });
-    this.content.add(this.detail);
-
-    const buttons = new HStack({ gap: Theme.gap, align: 'center' });
-    const upload = new Button('Upload…');
-    upload.onClick = this.closeThen(() => pickAndImportSounds(this.deps));
-    buttons.add(upload);
-    buttons.add(new Spacer(), 1);
-    const cancel = new Button('Cancel');
-    cancel.onClick = this.closeThen();
-    buttons.add(cancel);
-    this.use = new Button('Use sound', { variant: 'primary' });
-    this.use.onClick = () => this.confirm();
-    this.use.setEnabled(false);
-    buttons.add(this.use);
-    this.content.add(buttons);
-
-    void this.loadList();
+    super(
+      new SoundList(),
+      {
+        title: 'Choose a sound',
+        loading: 'Loading sounds…',
+        idle: IDLE_HINT,
+        empty: 'No sounds on the server yet – upload one.',
+        use: 'Use sound',
+        noun: 'sound',
+      },
+      () => pickAndImportSounds(deps),
+    );
   }
 
-  /** What the dialog offers, which of it the project already uses, and what is picked (test hook). */
-  debugInfo(): {
-    files: string[];
-    used: string[];
-    captions: string[];
-    selected: string | null;
-    played: string | null;
-  } {
-    return {
-      files: this.list.fileList,
-      used: this.list.usedFiles,
-      captions: this.list.captions,
-      selected: this.list.selected?.file ?? null,
-      played: this.list.lastPlayed,
-    };
+  override debugInfo(): ReturnType<FilePicker<SoundItem>['debugInfo']> & { played: string | null } {
+    return { ...super.debugInfo(), played: this.list.lastPlayed };
   }
 
   rowGlobal(file: string): { x: number; y: number } | null {
-    return this.list.rowGlobal(file);
+    return this.list.rowGlobal(file, PLAY_WIDTH);
   }
 
   playGlobal(file: string): { x: number; y: number } | null {
@@ -250,64 +111,27 @@ export class SoundPicker extends Popup {
 
   override close(): void {
     super.close();
-    if (current === this) current = null;
     // A preview left running would outlive the dialog that started it, with nothing left to stop it.
     soundLibrary.stopAll();
   }
 
-  private async loadList(): Promise<void> {
-    try {
-      const stored = await this.deps.sounds.list();
-      const named = new Map<string, string>();
-      for (const asset of this.deps.state.project.assets) {
-        if (asset.type === 'sound') named.set(asset.file, asset.name);
-      }
-      this.list.setItems(stored.map((item) => ({ ...item, assetName: named.get(item.file) ?? null })));
-      this.scroll.minHeight = Math.min(
-        this.roomFor(this.scroll, ROW_HEIGHT),
-        Math.max(ROW_HEIGHT, heightFor(stored.length)),
-      );
-      this.status.setText(
-        stored.length === 1 ? '1 sound on the server' : `${stored.length} sounds on the server`,
-      );
-    } catch (error) {
-      this.status.setText(
-        `Could not list the sounds: ${error instanceof Error ? error.message : String(error)}`,
-      );
-    }
-    this.refreshSelection();
+  protected async fetchItems(): Promise<SoundItem[]> {
+    return withAssetNames(await this.deps.sounds.list(), this.deps.state.project, 'sound');
   }
 
-  private refreshSelection(): void {
-    const item = this.list.selected;
-    this.use.setEnabled(item !== null);
-    this.detail.setText(item ? describe(item) : 'Press ▶ to hear one.');
-    this.refreshLayout();
+  protected contentHeight(count: number): { unit: number; total: number } {
+    return { unit: ROW_HEIGHT, total: this.list.heightFor(count) };
   }
 
-  private confirm(): void {
-    const item = this.list.selected;
-    if (!item) return;
-    this.close();
+  protected adopt(item: SoundItem): void {
     importStoredSound(item, this.deps);
   }
 }
 
-function describe(item: PickerItem): string {
-  const size = item.name ? `${item.name} – ${formatBytes(item.bytes)}` : formatBytes(item.bytes);
-  return item.assetName ? `${size} – already in the project as "${item.assetName}"` : size;
-}
-
-let current: SoundPicker | null = null;
-
 export function openSoundPicker(deps: SoundImportDeps): SoundPicker {
-  current?.close();
-  current = new SoundPicker(deps);
-  current.openCentered();
-  return current;
+  return openPicker(new SoundPicker(deps));
 }
 
-/** The open dialog, for the test hook. */
 export function currentSoundPicker(): SoundPicker | null {
-  return current;
+  return currentPicker(SoundPicker);
 }

src/editor/soundImport.ts

@@ -1,9 +1,7 @@
 import { CreateSoundCommand } from '../core/commands/assetCommands';
-import { nextAssetName } from '../core/commands/naming';
-import type { SoundAsset } from '../core/model/Asset';
 import type { SoundStore, UploadedSound } from '../core/store/SoundStore';
+import { type ImportKind, type ImportOutcome, importFiles, importStored, pickAndImport } from './assetImport';
 import type { EditorState } from './state';
-import { type ImportOutcome, assetNameForFile, importNotice } from './textureImport';
 
 /** What the file dialog offers and a drop accepts; the server rejects everything else anyway. */
 export const SOUND_ACCEPT = '.mp3,.ogg,.wav,.m4a';
@@ -23,83 +21,27 @@ export interface SoundImportDeps {
   sounds: SoundStore;
 }
 
-/** Sequential like `importImages`, so each asset is named against the project as it then stands. */
-export async function importSounds(files: readonly File[], deps: SoundImportDeps): Promise<ImportOutcome[]> {
-  if (files.length === 0) return [];
-  const outcomes: ImportOutcome[] = [];
-  for (const file of files) outcomes.push(await importSound(file, deps));
-  const created = outcomes.filter((outcome) => outcome.assetId !== null);
-  const last = created[created.length - 1];
-  if (last?.assetId) deps.state.select({ kind: 'asset', assetId: last.assetId });
-  deps.state.setNotice(importNotice(outcomes, 'sound'));
-  return outcomes;
+const SOUND_KIND: ImportKind<UploadedSound, SoundImportDeps> = {
+  type: 'sound',
+  noun: 'sound',
+  fallbackName: 'Sound',
+  store: (deps) => deps.sounds,
+  // The bytes go up untouched: nothing here could encode audio, and a re-encode would be a loss.
+  prepare: (file) =>
+    isSoundFileName(file.name)
+      ? Promise.resolve({ blob: file, type: file.type || 'application/octet-stream' })
+      : Promise.reject(new Error('Not a sound file – use MP3, OGG, WAV or M4A.')),
+  create: (name, sound) => new CreateSoundCommand(name, sound.file),
+};
+
+export function importSounds(files: readonly File[], deps: SoundImportDeps): Promise<ImportOutcome[]> {
+  return importFiles(SOUND_KIND, files, deps);
 }
 
-async function importSound(file: File, deps: SoundImportDeps): Promise<ImportOutcome> {
-  try {
-    if (!isSoundFileName(file.name)) throw new Error('Not a sound file – use MP3, OGG, WAV or M4A.');
-    // The bytes go up untouched: nothing here could encode audio, and a re-encode would be a loss.
-    const uploaded = await deps.sounds.upload(file, file.type || 'application/octet-stream', file.name);
-    return adopt(uploaded, assetNameForFile(file.name, 'Sound'), file.name, deps);
-  } catch (error) {
-    return {
-      name: file.name,
-      assetId: null,
-      error: error instanceof Error ? error.message : String(error),
-    };
-  }
-}
-
-/** Makes an asset for a sound the server holds, or reuses the one already naming those bytes. */
-function adopt(sound: UploadedSound, nameBase: string, label: string, deps: SoundImportDeps): ImportOutcome {
-  const existing = deps.state.project.assets.find(
-    (asset): asset is SoundAsset => asset.type === 'sound' && asset.file === sound.file,
-  );
-  if (existing) return { name: label, assetId: existing.id, error: null, reused: true };
-
-  const name = nextAssetName(deps.state.project, nameBase);
-  const command = new CreateSoundCommand(name, sound.file);
-  // A rejected command has already put its reason into the notice; that is the message here.
-  if (!deps.state.execute(command)) return { name: label, assetId: null, error: deps.state.notice };
-  return { name: label, assetId: command.asset.id, error: null, reused: false };
-}
-
-/**
- * Adopts a sound the server already holds – no upload, the bytes are there. Chosen in the picker,
- * so this is "+ → Sound" and the asset is selected the way a created one would be.
- */
 export function importStoredSound(sound: UploadedSound, deps: SoundImportDeps): ImportOutcome {
-  const outcome = adopt(sound, assetNameForFile(sound.name, 'Sound'), sound.name || sound.file, deps);
-  if (outcome.assetId) deps.state.select({ kind: 'asset', assetId: outcome.assetId });
-  deps.state.setNotice(
-    outcome.error ??
-      (outcome.reused ? 'That sound is already in the project.' : 'Added the sound to the project.'),
-  );
-  return outcome;
-}
-
-/** Opens the browser's file dialog; resolves empty when the dialog was cancelled. */
-export function pickSoundFiles(): Promise<File[]> {
-  return new Promise((resolve) => {
-    const input = document.createElement('input');
-    input.type = 'file';
-    input.accept = SOUND_ACCEPT;
-    input.multiple = true;
-    input.style.display = 'none';
-    document.body.appendChild(input);
-    const finish = (files: File[]) => {
-      input.remove();
-      resolve(files);
-    };
-    input.addEventListener('change', () => finish([...(input.files ?? [])]));
-    // Without `cancel` a dismissed dialog leaves both the element and this promise behind.
-    input.addEventListener('cancel', () => finish([]));
-    input.click();
-  });
+  return importStored(SOUND_KIND, sound, deps);
 }
 
 export function pickAndImportSounds(deps: SoundImportDeps): void {
-  void pickSoundFiles()
-    .then((files) => importSounds(files, deps))
-    .catch((error: unknown) => deps.state.setNotice(String(error), 'error'));
+  pickAndImport(SOUND_KIND, SOUND_ACCEPT, deps);
 }

src/editor/texture/ImagePicker.ts

@@ -1,108 +1,46 @@
-import { Container, type FederatedPointerEvent, Graphics, Sprite, Text } from 'pixi.js';
+import { Container, Graphics, Sprite, Text } from 'pixi.js';
 import type { StoredTexture } from '../../core/store/TextureStore';
-import {
-  Button,
-  drawControlBox,
-  formatBytes,
-  HStack,
-  Label,
-  Popup,
-  pressCount,
-  ScrollContainer,
-  type Size,
-  Spacer,
-  Theme,
-  textStyle,
-  truncate,
-  Widget,
-} from '../../ui';
+import { formatBytes, type Size, textStyle, truncate } from '../../ui';
 import { textureLibrary } from '../../viewport/TextureLibrary';
-import { importStoredImage, pickAndImport, type TextureImportDeps } from '../textureImport';
+import {
+  currentPicker,
+  FilePicker,
+  openPicker,
+  PICKER_WIDTH,
+  PickerList,
+  type PickerItem,
+  type PickerRow,
+  withAssetNames,
+} from '../FilePicker';
+import { importStoredImage, pickAndImportImages, type TextureImportDeps } from '../textureImport';
 import { CAPTION_HEIGHT, containRect, gridMetrics, type GridMetrics, tileAt, tileRect } from './imageGrid';
 
-/** The dialog keeps this size whatever the list turns out to be, so it does not jump on opening. */
-const GRID_WIDTH = 560;
-const GRID_HEIGHT = 340;
 /** Inset of the picture inside its tile, so the selection frame stays visible around it. */
 const TILE_PAD = 4;
 
-/** One offered picture, with the asset that already wears it (if any). */
-interface PickerItem extends StoredTexture {
-  assetName: string | null;
+type ImageItem = PickerItem<StoredTexture>;
+interface Tile extends PickerRow {
+  sprite: Sprite;
 }
 
 /**
- * The tiles. Pictures come from the shared `textureLibrary`, which keys by file name, so a
- * thumbnail of a picture the scene already draws costs no second upload to the GPU.
+ * Pictures come from the shared `textureLibrary`, which keys by file name, so a thumbnail of a
+ * picture the scene already draws costs no second upload to the GPU.
  */
-class ImageGrid extends Widget {
-  private items: PickerItem[] = [];
-  private tiles: { box: Container; background: Graphics; sprite: Sprite; caption: Text }[] = [];
-  private metrics: GridMetrics = gridMetrics(GRID_WIDTH, 0);
-  private selectedFile: string | null = null;
-  private readonly empty = new Text({ text: '', style: textStyle('muted') });
-  private readonly stopWatching: () => void;
-  onPick?: (file: string) => void;
-  onActivate?: (file: string) => void;
-  emptyText = '';
+class ImageGrid extends PickerList<ImageItem, Tile> {
+  private metrics: GridMetrics = gridMetrics(PICKER_WIDTH, 0);
 
   constructor() {
     super();
-    this.addChild(this.empty);
-    this.on('pointerdown', (e: FederatedPointerEvent) => this.onPress(e));
-    this.stopWatching = textureLibrary.onChange(() => this.invalidate());
-  }
-
-  setItems(items: PickerItem[]): void {
-    this.items = items;
-    for (const tile of this.tiles) tile.box.destroy({ children: true });
-    this.tiles = items.map(() => {
-      // A Container holding the background, not a Graphics with children: Pixi v8 only lets
-      // containers have them (`addChild: Only Containers will be allowed to add children`).
-      const box = new Container();
-      const background = new Graphics();
-      const sprite = new Sprite();
-      const caption = new Text({ style: textStyle('small') });
-      box.addChild(background, sprite, caption);
-      this.addChild(box);
-      return { box, background, sprite, caption };
-    });
-    if (!items.some((item) => item.file === this.selectedFile)) this.selectedFile = null;
-    this.layout();
-    this.redraw();
-  }
-
-  get selected(): PickerItem | null {
-    return this.items.find((item) => item.file === this.selectedFile) ?? null;
-  }
-
-  get fileList(): string[] {
-    return this.items.map((item) => item.file);
-  }
-
-  get usedFiles(): string[] {
-    return this.items.filter((item) => item.assetName !== null).map((item) => item.file);
-  }
-
-  /** The captions as drawn, read off the tiles themselves rather than recomputed (test hook). */
-  get captions(): string[] {
-    return this.tiles.map((tile) => tile.caption.text);
-  }
-
-  select(file: string | null): void {
-    if (file === this.selectedFile) return;
-    this.selectedFile = file;
-    this.redraw();
-    if (file) this.onPick?.(file);
+    this.watch(textureLibrary, () => this.invalidate());
   }
 
   /** Global centre of a tile; null when the file is not offered (test hook). */
   tileGlobal(file: string): { x: number; y: number } | null {
-    const index = this.items.findIndex((item) => item.file === file);
-    const tile = this.tiles[index];
-    if (!tile) return null;
-    const rect = tileRect(index, this.metrics);
-    const p = tile.box.getGlobalPosition();
+    const found = this.rowOf(file);
+    if (!found) return null;
+    const rect = tileRect(found.index, this.metrics);
+    const p = found.row.box.getGlobalPosition();
     return { x: p.x + rect.w / 2, y: p.y + this.metrics.tile / 2 };
   }
 
@@ -115,190 +53,101 @@ class ImageGrid extends Widget {
 
   override layout(): void {
     this.metrics = gridMetrics(this.w, this.items.length);
-    this.tiles.forEach((tile, index) => {
+    this.rows.forEach((tile, index) => {
       const rect = tileRect(index, this.metrics);
       tile.box.position.set(rect.x, rect.y);
     });
   }
 
-  override redraw(): void {
-    const { tile: side } = this.metrics;
+  protected buildRow(): Tile {
+    const box = new Container();
+    const background = new Graphics();
+    const sprite = new Sprite();
+    const caption = new Text({ style: textStyle('small') });
+    box.addChild(background, sprite, caption);
+    return { box, background, sprite, caption };
+  }
+
+  protected indexAt(x: number, y: number): number {
+    return tileAt(x, y, this.items.length, this.metrics);
+  }
+
+  protected redrawRow(tile: Tile, item: ImageItem, selected: boolean): void {
+    const side = this.metrics.tile;
     const inner = side - TILE_PAD * 2;
-    this.empty.text = this.items.length === 0 ? this.emptyText : '';
-    this.empty.position.set(0, 0);
+    this.drawBox(tile, side, side, selected);
 
-    this.tiles.forEach((node, index) => {
-      const item = this.items[index];
-      if (!item) return;
-      const selected = item.file === this.selectedFile;
-      node.background.clear();
-      drawControlBox(node.background, side, side, {
-        fill: selected ? Theme.colors.selection : Theme.colors.control,
-        border: selected ? Theme.colors.accent : Theme.colors.border,
-      });
+    const texture = item.width > 0 ? textureLibrary.load(item.file) : null;
+    tile.sprite.visible = texture !== null;
+    if (texture) {
+      const fitted = containRect(item.width, item.height, inner, inner);
+      tile.sprite.texture = texture;
+      tile.sprite.position.set(TILE_PAD + fitted.x, TILE_PAD + fitted.y);
+      tile.sprite.width = fitted.w;
+      tile.sprite.height = fitted.h;
+    }
 
-      const texture = item.width > 0 ? textureLibrary.load(item.file) : null;
-      node.sprite.visible = texture !== null;
-      if (texture) {
-        const fitted = containRect(item.width, item.height, inner, inner);
-        node.sprite.texture = texture;
-        node.sprite.position.set(TILE_PAD + fitted.x, TILE_PAD + fitted.y);
-        node.sprite.width = fitted.w;
-        node.sprite.height = fitted.h;
-      }
-
-      // The asset name is the useful caption where there is one, then the name the file was
-      // uploaded under; a bare hash tells nobody anything, and the size is the last resort.
-      const text =
-        item.width > 0 ? (item.assetName ?? (item.name || `${item.width} × ${item.height}`)) : 'unreadable';
-      node.caption.style = textStyle(item.assetName ? 'accent' : 'muted');
-      node.caption.text = truncate(text, node.caption.style, side);
-      node.caption.position.set(0, side + 1);
-    });
-  }
-
-  override destroy(): void {
-    this.stopWatching();
-    super.destroy({ children: true });
-  }
-
-  private onPress(e: FederatedPointerEvent): void {
-    const local = this.toLocal(e.global);
-    const index = tileAt(local.x, local.y, this.items.length, this.metrics);
-    const item = this.items[index];
-    if (!item) return;
-    this.select(item.file);
-    if (pressCount(e, item.file) === 2) this.onActivate?.(item.file);
+    // The asset name is the useful caption where there is one, then the name the file was
+    // uploaded under; a bare hash tells nobody anything, and the size is the last resort.
+    const text =
+      item.width > 0 ? (item.assetName ?? (item.name || `${item.width} × ${item.height}`)) : 'unreadable';
+    tile.caption.style = textStyle(item.assetName ? 'accent' : 'muted');
+    tile.caption.text = truncate(text, tile.caption.style, side);
+    tile.caption.position.set(0, side + 1);
   }
 }
 
-/**
- * Offers every picture the server holds, rather than the machine's file system: uploading the
- * same image twice is wasteful, and nothing collects the files a project stopped referencing.
- * Uploading is still one button away, for a picture the server does not have yet.
- */
-export class ImagePicker extends Popup {
-  private readonly grid = new ImageGrid();
-  private readonly scroll = new ScrollContainer();
-  private readonly status: Label;
-  private readonly detail: Label;
-  private readonly use: Button;
+export class ImagePicker extends FilePicker<ImageItem> {
+  declare protected readonly list: ImageGrid;
 
   constructor(private readonly deps: TextureImportDeps) {
-    super({ modal: true, padding: Theme.padding * 2, gap: Theme.gap });
-    this.content.add(new Label('Choose an image', { style: 'bodyBold' }));
-    this.status = new Label('Loading images…', { style: 'muted' });
-    this.content.add(this.status);
-
-    this.grid.minWidth = GRID_WIDTH;
-    this.grid.emptyText = 'No images on the server yet – upload one.';
-    this.grid.onPick = () => this.refreshSelection();
-    this.grid.onActivate = () => this.confirm();
-    this.scroll.minWidth = GRID_WIDTH;
-    this.scroll.minHeight = GRID_HEIGHT;
-    this.scroll.setContent(this.grid);
-    this.content.add(this.scroll);
-
-    this.detail = new Label('', { style: 'muted' });
-    this.content.add(this.detail);
-
-    const buttons = new HStack({ gap: Theme.gap, align: 'center' });
-    const upload = new Button('Upload…');
-    upload.onClick = this.closeThen(() => pickAndImport(this.deps));
-    buttons.add(upload);
-    buttons.add(new Spacer(), 1);
-    const cancel = new Button('Cancel');
-    cancel.onClick = this.closeThen();
-    buttons.add(cancel);
-    this.use = new Button('Use image', { variant: 'primary' });
-    this.use.onClick = () => this.confirm();
-    this.use.setEnabled(false);
-    buttons.add(this.use);
-    this.content.add(buttons);
-
-    void this.loadList();
-  }
-
-  /** What the dialog offers, which of it the project already wears, and what is picked (test hook). */
-  debugInfo(): { files: string[]; used: string[]; captions: string[]; selected: string | null } {
-    return {
-      files: this.grid.fileList,
-      used: this.grid.usedFiles,
-      captions: this.grid.captions,
-      selected: this.grid.selected?.file ?? null,
-    };
+    super(
+      new ImageGrid(),
+      {
+        title: 'Choose an image',
+        loading: 'Loading images…',
+        empty: 'No images on the server yet – upload one.',
+        use: 'Use image',
+        noun: 'image',
+      },
+      () => pickAndImportImages(deps),
+    );
   }
 
   tileGlobal(file: string): { x: number; y: number } | null {
-    return this.grid.tileGlobal(file);
+    return this.list.tileGlobal(file);
   }
 
-  override close(): void {
-    super.close();
-    if (current === this) current = null;
-    // Escape, Cancel and a confirmed pick all land here, and `Popup.close` tolerates a second
-    // call; the grid's listener must be dropped exactly once.
-    if (!this.grid.destroyed) this.grid.destroy();
+  protected async fetchItems(): Promise<ImageItem[]> {
+    return withAssetNames(await this.deps.textures.list(), this.deps.state.project, 'texture');
   }
 
-  private async loadList(): Promise<void> {
-    try {
-      const stored = await this.deps.textures.list();
-      const named = new Map<string, string>();
-      for (const asset of this.deps.state.project.assets) {
-        if (asset.type === 'texture') named.set(asset.file, asset.name);
-      }
-      this.grid.setItems(stored.map((item) => ({ ...item, assetName: named.get(item.file) ?? null })));
-      // Only as tall as the tiles need, up to the cap: a handful of pictures should not leave
-      // half a dialog of empty box under them.
-      const metrics = gridMetrics(GRID_WIDTH, stored.length);
-      this.scroll.minHeight = Math.min(
-        this.roomFor(this.scroll, metrics.tile + CAPTION_HEIGHT),
-        Math.max(metrics.tile + CAPTION_HEIGHT, metrics.height),
-      );
-      this.status.setText(
-        stored.length === 1 ? '1 image on the server' : `${stored.length} images on the server`,
-      );
-    } catch (error) {
-      this.status.setText(
-        `Could not list the images: ${error instanceof Error ? error.message : String(error)}`,
-      );
-    }
-    this.refreshSelection();
+  protected contentHeight(count: number): { unit: number; total: number } {
+    const metrics = gridMetrics(PICKER_WIDTH, count);
+    return { unit: metrics.tile + CAPTION_HEIGHT, total: metrics.height };
   }
 
-  private refreshSelection(): void {
-    const item = this.grid.selected;
-    this.use.setEnabled(item !== null && item.width > 0);
-    this.detail.setText(item ? describe(item) : '');
-    this.refreshLayout();
+  /** A file the server could not read as an image has no size and cannot become an asset. */
+  protected override canUse(item: ImageItem): boolean {
+    return item.width > 0;
   }
 
-  private confirm(): void {
-    const item = this.grid.selected;
-    if (!item || item.width <= 0) return;
-    this.close();
+  protected override describe(item: ImageItem): string {
+    if (item.width <= 0) return 'The server cannot read this file as an image.';
+    const measurements = `${item.width} × ${item.height} px, ${formatBytes(item.bytes)}`;
+    const size = item.name ? `${item.name} – ${measurements}` : measurements;
+    return item.assetName ? `${size} – already in the project as "${item.assetName}"` : size;
+  }
+
+  protected adopt(item: ImageItem): void {
     importStoredImage(item, this.deps);
   }
 }
 
-function describe(item: PickerItem): string {
-  if (item.width <= 0) return 'The server cannot read this file as an image.';
-  const measurements = `${item.width} × ${item.height} px, ${formatBytes(item.bytes)}`;
-  const size = item.name ? `${item.name} – ${measurements}` : measurements;
-  return item.assetName ? `${size} – already in the project as "${item.assetName}"` : size;
-}
-
-let current: ImagePicker | null = null;
-
 export function openImagePicker(deps: TextureImportDeps): ImagePicker {
-  current?.close();
-  current = new ImagePicker(deps);
-  current.openCentered();
-  return current;
+  return openPicker(new ImagePicker(deps));
 }
 
-/** The open dialog, for the test hook. */
 export function currentImagePicker(): ImagePicker | null {
-  return current;
+  return currentPicker(ImagePicker);
 }

src/editor/textureImport.ts

@@ -1,8 +1,7 @@
 import { CreateTextureCommand } from '../core/commands/assetCommands';
-import { nextAssetName } from '../core/commands/naming';
-import type { TextureAsset } from '../core/model/Asset';
 import type { TextureStore, UploadedTexture } from '../core/store/TextureStore';
 import { formatBytes } from '../ui';
+import { type ImportKind, type ImportOutcome, importFiles, importStored, pickAndImport } from './assetImport';
 import type { EditorState } from './state';
 
 /** What the picker offers and a drop accepts; the server rejects everything else anyway. */
@@ -91,145 +90,23 @@ export interface TextureImportDeps {
   textures: TextureStore;
 }
 
-/** One file's outcome; exactly one of `assetId` and `error` is set. */
-export interface ImportOutcome {
-  name: string;
-  assetId: string | null;
-  error: string | null;
-  /** The project already had this exact picture, so its existing asset was used instead. */
-  reused?: boolean;
+const IMAGE_KIND: ImportKind<UploadedTexture, TextureImportDeps> = {
+  type: 'texture',
+  noun: 'image',
+  fallbackName: 'Texture',
+  store: (deps) => deps.textures,
+  prepare: prepareImage,
+  create: (name, image) => new CreateTextureCommand(name, image),
+};
+
+export function importImages(files: readonly File[], deps: TextureImportDeps): Promise<ImportOutcome[]> {
+  return importFiles(IMAGE_KIND, files, deps);
 }
 
-/**
- * Imports the files sequentially, so each asset is named against the project as the previous one
- * left it. A file that fails is reported in the notice; the remaining ones are still imported.
- */
-export async function importImages(
-  files: readonly File[],
-  deps: TextureImportDeps,
-): Promise<ImportOutcome[]> {
-  if (files.length === 0) return [];
-  const outcomes: ImportOutcome[] = [];
-  for (const file of files) outcomes.push(await importImage(file, deps));
-  selectLast(outcomes, deps);
-  deps.state.setNotice(importNotice(outcomes));
-  return outcomes;
-}
-
-async function importImage(file: File, deps: TextureImportDeps): Promise<ImportOutcome> {
-  try {
-    const image = await prepareImage(file);
-    const uploaded = await deps.textures.upload(image.blob, image.type, file.name);
-    return adopt(uploaded, assetNameForFile(file.name, 'Texture'), file.name, deps);
-  } catch (error) {
-    return { name: file.name, assetId: null, error: error instanceof Error ? error.message : String(error) };
-  }
-}
-
-/**
- * Makes an asset for a file the server holds. `label` names the source in messages, `nameBase` is
- * what the asset is called.
- */
-function adopt(
-  image: UploadedTexture,
-  nameBase: string,
-  label: string,
-  deps: TextureImportDeps,
-): ImportOutcome {
-  // The server stores by content hash, so a re-imported picture comes back as the file the
-  // project already references; two assets on one file would disagree about `filter`.
-  const existing = deps.state.project.assets.find(
-    (asset): asset is TextureAsset => asset.type === 'texture' && asset.file === image.file,
-  );
-  if (existing) return { name: label, assetId: existing.id, error: null, reused: true };
-
-  const name = nextAssetName(deps.state.project, nameBase);
-  const command = new CreateTextureCommand(name, image);
-  // A rejected command has already put its reason into the notice; that is the message here.
-  if (!deps.state.execute(command)) return { name: label, assetId: null, error: deps.state.notice };
-  return { name: label, assetId: command.asset.id, error: null, reused: false };
-}
-
-/**
- * Adopts a picture the server already holds – no upload, the bytes are there. Nothing collects
- * unreferenced files, so a picture one project dropped is still there for the next to pick up.
- */
 export function importStoredImage(image: UploadedTexture, deps: TextureImportDeps): ImportOutcome {
-  // The name it was uploaded under is what the asset is called, the same as for a dropped file;
-  // a file from before names were kept has none, and falls back to "Texture" as it always did.
-  const outcome = adopt(image, assetNameForFile(image.name, 'Texture'), image.name || image.file, deps);
-  // Chosen in the picker, so this is "+ → Texture": the tab opens like for any created asset. A
-  // pasted or dropped picture (`importImages`) only selects – it usually goes into the scene.
-  if (outcome.assetId) deps.state.openAsset(outcome.assetId);
-  deps.state.setNotice(
-    outcome.error ??
-      (outcome.reused ? 'That image is already in the project.' : 'Added the image to the project.'),
-  );
-  return outcome;
+  return importStored(IMAGE_KIND, image, deps);
 }
 
-/** Selects the asset the batch created last, so the panel shows what just arrived. */
-function selectLast(outcomes: readonly ImportOutcome[], deps: TextureImportDeps): void {
-  const created = outcomes.filter((outcome) => outcome.assetId !== null);
-  const last = created[created.length - 1];
-  if (last?.assetId) deps.state.select({ kind: 'asset', assetId: last.assetId });
-}
-
-/**
- * One line for the whole batch; reuse is worded apart, since "Imported 1 image" would be a lie.
- * `noun` names what was imported – fonts come through the same batch reporting.
- */
-export function importNotice(outcomes: readonly ImportOutcome[], noun = 'image'): string {
-  const added = outcomes.filter((outcome) => outcome.assetId !== null && !outcome.reused).length;
-  const reused = outcomes.filter((outcome) => outcome.reused).length;
-  const failed = outcomes.filter((outcome) => outcome.error !== null);
-  const first = failed[0];
-
-  const known = reused === 0 ? '' : ` ${reused === 1 ? 'One was' : `${reused} were`} already in the project.`;
-
-  if (!first) {
-    if (added === 0 && reused > 0)
-      return reused === 1
-        ? `That ${noun} is already in the project.`
-        : `Those ${reused} ${noun}s are already in the project.`;
-    return `Imported ${added} ${added === 1 ? noun : `${noun}s`}.${known}`;
-  }
-  const more = failed.length > 1 ? ` (and ${failed.length - 1} more)` : '';
-  const problem = `Could not import "${first.name}": ${first.error ?? ''}${more}`;
-  if (added + reused === 0) return problem;
-  return `Imported ${added + reused} of ${outcomes.length}.${known} ${problem}`;
-}
-
-/**
- * A file name without its extension, as an asset is called: "hero-idle.png" reads better than
- * "Texture 3". Shared with the picker, which gets the same name back from the server.
- */
-export function assetNameForFile(fileName: string, fallback: string): string {
-  return fileName.replace(/\.[^.]+$/, '').trim() || fallback;
-}
-
-/** Opens the browser's file dialog; resolves empty when the dialog was cancelled. */
-export function pickImageFiles(): Promise<File[]> {
-  return new Promise((resolve) => {
-    const input = document.createElement('input');
-    input.type = 'file';
-    input.accept = IMAGE_ACCEPT;
-    input.multiple = true;
-    input.style.display = 'none';
-    document.body.appendChild(input);
-    const finish = (files: File[]) => {
-      input.remove();
-      resolve(files);
-    };
-    input.addEventListener('change', () => finish([...(input.files ?? [])]));
-    // Without `cancel` a dismissed dialog leaves both the element and this promise behind.
-    input.addEventListener('cancel', () => finish([]));
-    input.click();
-  });
-}
-
-export function pickAndImport(deps: TextureImportDeps): void {
-  void pickImageFiles()
-    .then((files) => importImages(files, deps))
-    .catch((error: unknown) => deps.state.setNotice(String(error), 'error'));
+export function pickAndImportImages(deps: TextureImportDeps): void {
+  pickAndImport(IMAGE_KIND, IMAGE_ACCEPT, deps);
 }

src/viewport/ParticleLibrary.ts

@@ -1,5 +1,6 @@
 import type { ParticlesAsset } from '../core/model/Asset';
-import { compileParticles, type ParticlesBuild, particlesFingerprint } from '../core/particles/compile';
+import { graphFingerprint } from '../core/graph/Graph';
+import { compileParticles, type ParticlesBuild } from '../core/particles/compile';
 import { gameClock } from '../core/time';
 
 /**
@@ -22,12 +23,8 @@ export class ParticleLibrary {
     this.frozenAt = at;
   }
 
-  get frozen(): number | null {
-    return this.frozenAt;
-  }
-
   buildFor(asset: ParticlesAsset): ParticlesBuild {
-    const fingerprint = particlesFingerprint(asset.graph);
+    const fingerprint = graphFingerprint(asset.graph);
     const cached = this.builds.get(asset.id);
     if (cached && cached.fingerprint === fingerprint) return cached.build;
     this.compiles += 1;

src/viewport/ShaderLibrary.ts

@@ -1,6 +1,7 @@
 import type { ShaderAsset } from '../core/model/Asset';
 import { findAssetOf, type Project } from '../core/model/Project';
-import { compileShader, shaderFingerprint, type ShaderBuild } from '../core/shader/compile';
+import { graphFingerprint } from '../core/graph/Graph';
+import { compileShader, type ShaderBuild } from '../core/shader/compile';
 import { gameClock } from '../core/time';
 import type { ShaderSource } from './shaders';
 
@@ -25,7 +26,7 @@ export class ShaderLibrary {
   }
 
   buildFor(asset: ShaderAsset): ShaderBuild {
-    const fingerprint = shaderFingerprint(asset.graph);
+    const fingerprint = graphFingerprint(asset.graph);
     const cached = this.builds.get(asset.id);
     if (cached && cached.fingerprint === fingerprint) return cached.build;
     this.compiles += 1;

src/viewport/shaders.ts

@@ -110,42 +110,58 @@ function readUniforms(
 }
 
 /**
- * A shader asset worn by one sprite mesh: the fragment replaces Pixi's in the sprite's own draw,
- * so there is no filter and no extra pass (#77). The program is shared (`GlProgram.from` caches
- * by source), the uniforms are this sprite's; `read` takes them from the item's bag.
+ * A compiled graph as a Pixi program. The program is shared (`GlProgram.from` caches by source),
+ * the uniforms are this wearer's; `read` takes them from the item's bag. `resources` are the slots
+ * Pixi fills for the vertex stage in question – `Shader.resources` only accepts the slots its
+ * constructor declared, so a subclass names them all up front.
  */
-class GraphShader extends Shader {
+abstract class CompiledGraphShader extends Shader {
   private readonly uniforms: Record<string, number> | null;
   private readonly compiled: CompiledShader;
   readonly fragment: string;
-  /** What `Mesh.shader` asks of a shader; kept in step with the mesh's own by `wear`. */
-  texture: Texture = Texture.WHITE;
 
   constructor(
     readonly assetId: string,
     compiled: CompiledShader,
+    program: { vertex: string; name: string },
+    resources: Record<string, unknown>,
   ) {
     const group = uniformGroupOf(compiled);
     super({
-      glProgram: GlProgram.from({
-        vertex: SPRITE_VERTEX,
-        fragment: compiled.fragment,
-        name: `shader-${assetId}`,
-      }),
-      resources: {
-        uTexture: Texture.WHITE.source,
-        uSampler: Texture.WHITE.source.style,
-        ...(group ? { shaderUniforms: group } : {}),
-      },
+      glProgram: GlProgram.from({ vertex: program.vertex, fragment: compiled.fragment, name: program.name }),
+      resources: { ...resources, ...(group ? { shaderUniforms: group } : {}) },
     });
     this.fragment = compiled.fragment;
     this.compiled = compiled;
     this.uniforms = group ? group.uniforms : null;
   }
 
+  /** True while this is still the shader `props` ask for, so it can be updated instead of rebuilt. */
+  wears(id: string, compiled: CompiledShader): boolean {
+    return this.assetId === id && this.fragment === compiled.fragment;
+  }
+
   read(props: PropertyBag, now: number): void {
     if (this.uniforms) readUniforms(this.uniforms, this.compiled, props, now);
   }
+}
+
+/**
+ * A shader asset worn by one sprite mesh: the fragment replaces Pixi's in the sprite's own draw,
+ * so there is no filter and no extra pass (#77).
+ */
+class GraphShader extends CompiledGraphShader {
+  /** What `Mesh.shader` asks of a shader; kept in step with the mesh's own by `wear`. */
+  texture: Texture = Texture.WHITE;
+
+  constructor(assetId: string, compiled: CompiledShader) {
+    super(
+      assetId,
+      compiled,
+      { vertex: SPRITE_VERTEX, name: `shader-${assetId}` },
+      { uTexture: Texture.WHITE.source, uSampler: Texture.WHITE.source.style },
+    );
+  }
 
   /** Pixi binds a mesh's texture only for its own shader, so a custom one takes it here. */
   wear(texture: Texture): void {
@@ -168,7 +184,7 @@ export function syncShader(mesh: Mesh, props: PropertyBag, shaders: ShaderSource
   const id = shaderOf(props);
   const compiled = id ? shaders.compiled(id) : null;
   const worn = wornBy(mesh);
-  if (worn && compiled && worn.assetId === id && worn.fragment === compiled.fragment) {
+  if (worn && compiled && worn.wears(id, compiled)) {
     worn.read(props, shaders.now);
     worn.wear(mesh.texture);
     return;
@@ -195,26 +211,15 @@ export function syncShader(mesh: Mesh, props: PropertyBag, shaders: ShaderSource
  * The pipe breaks the batch for every field anyway, so unlike a shaded sprite (#77) this costs no
  * draw call at all: five hundred shaded particles are the one call five hundred plain ones were.
  */
-class ParticleGraphShader extends Shader {
-  private readonly uniforms: Record<string, number> | null;
-  private readonly compiled: CompiledShader;
-  readonly fragment: string;
-
-  constructor(
-    readonly assetId: string,
-    compiled: CompiledShader,
-  ) {
-    const group = uniformGroupOf(compiled);
-    super({
-      glProgram: GlProgram.from({
-        vertex: PARTICLE_VERTEX,
-        fragment: compiled.fragment,
-        name: `particle-shader-${assetId}`,
-      }),
-      // `GlParticleContainerAdaptor` writes the field's texture and the pipe's own uniforms into
-      // whichever shader the container names – but `Shader.resources` only accepts the slots its
-      // constructor declared, so both have to be here, empty, for Pixi to fill them.
-      resources: {
+class ParticleGraphShader extends CompiledGraphShader {
+  constructor(assetId: string, compiled: CompiledShader) {
+    // `GlParticleContainerAdaptor` writes the field's texture and the pipe's own uniforms into
+    // whichever shader the container names, so both slots have to exist, empty, for Pixi to fill.
+    super(
+      assetId,
+      compiled,
+      { vertex: PARTICLE_VERTEX, name: `particle-shader-${assetId}` },
+      {
         uTexture: Texture.WHITE.source,
         uSampler: new TextureStyle({}),
         uniforms: {
@@ -223,16 +228,8 @@ class ParticleGraphShader extends Shader {
           uRound: { value: 1, type: 'f32' },
           uResolution: { value: [0, 0], type: 'vec2<f32>' },
         },
-        ...(group ? { shaderUniforms: group } : {}),
       },
-    });
-    this.fragment = compiled.fragment;
-    this.compiled = compiled;
-    this.uniforms = group ? group.uniforms : null;
-  }
-
-  read(props: PropertyBag, now: number): void {
-    if (this.uniforms) readUniforms(this.uniforms, this.compiled, props, now);
+    );
   }
 }
 
@@ -249,7 +246,7 @@ export function syncParticleShader(
   const id = shaderOf(props);
   const compiled = id ? shaders.compiled(id) : null;
   const worn = wornByField(container);
-  if (worn && compiled && worn.assetId === id && worn.fragment === compiled.fragment) {
+  if (worn && compiled && worn.wears(id, compiled)) {
     worn.read(props, shaders.now);
     return;
   }