refactor(driver): text render

packages/driver/src/js/renderer/index.ts

@@ -1,3 +1,3 @@
 export { Renderer } from "./renderer.ts";
-export { TextRasterizer } from "./text.ts";
+export * from "./text.ts";
 export { WebGL1Backend } from "./webgl_backend.ts";

packages/driver/src/js/renderer/text.ts

@@ -64,17 +64,19 @@ export class TextMetrics {
   }
 }
 
-export class TextRasterizer {
-  private readonly cache: Map<string, { width: number; bitmap: TextureBitmap | undefined }> = new Map();
-  private readonly maxTextureSize: number;
+export interface TextRender {
+  width: number;
+  bitmap: TextureBitmap | undefined;
+}
 
-  constructor(readonly textMetrics: TextMetrics) {
-    const canvas = new OffscreenCanvas(1, 1);
-    const gl = canvas.getContext("webgl");
-    if (gl) {
-      this.maxTextureSize = gl.getParameter(gl.MAX_TEXTURE_SIZE) as number;
-    }
-  }
+export interface TextRasterizer {
+  get(size: number, fontNum: number, text: string): TextRender;
+}
+
+export class SimpleTextRasterizer implements TextRasterizer {
+  private readonly cache: Map<string, TextRender> = new Map();
+
+  constructor(readonly textMetrics: TextMetrics) {}
 
   get(size: number, fontNum: number, text: string) {
     const key = `${size}:${fontNum}:${text}`;
@@ -104,3 +106,15 @@ export class TextRasterizer {
     return bitmap;
   }
 }
+
+export class BinPackingTextRasterizer {
+  private readonly maxTextureSize: number;
+
+  constructor(readonly textMetrics: TextMetrics) {
+    const canvas = new OffscreenCanvas(1, 1);
+    const gl = canvas.getContext("webgl");
+    if (gl) {
+      this.maxTextureSize = gl.getParameter(gl.MAX_TEXTURE_SIZE) as number;
+    }
+  }
+}

packages/driver/src/js/worker.ts

@@ -6,8 +6,7 @@ import type { UIState } from "./event.ts";
 import { ImageRepository } from "./image";
 // @ts-ignore
 import { createNODEFS } from "./nodefs.js";
-import { Renderer, TextRasterizer, WebGL1Backend } from "./renderer";
-import { TextMetrics, loadFonts } from "./renderer/text.ts";
+import { Renderer, SimpleTextRasterizer, TextMetrics, type TextRasterizer, WebGL1Backend, loadFonts } from "./renderer";
 
 interface DriverModule extends EmscriptenModule {
   FS: typeof FS;
@@ -84,7 +83,7 @@ export class DriverWorker {
 
     await loadFonts();
     this.textMetrics = new TextMetrics();
-    this.textRasterizer = new TextRasterizer(this.textMetrics);
+    this.textRasterizer = new SimpleTextRasterizer(this.textMetrics);
 
     this.renderer = new Renderer(this.imageRepo, this.textRasterizer, this.screenSize);
     this.hostCallbacks = {