Encode FontPath data into an ArrayBuffer

Serialize FontPath commands into a binary format
and store it in an ArrayBuffer so that it can
eventually be stored in a SharedArrayBuffer.

Author: ryzokuken

src/core/evaluator.js

@@ -40,6 +40,7 @@ import {
   lookupMatrix,
   lookupNormalRect,
 } from "./core_utils.js";
+import { FontInfo, FontPathInfo } from "../shared/obj-bin-transform.js";
 import {
   getEncoding,
   MacRomanEncoding,
@@ -72,7 +73,6 @@ import { BaseStream } from "./base_stream.js";
 import { bidi } from "./bidi.js";
 import { ColorSpace } from "./colorspace.js";
 import { ColorSpaceUtils } from "./colorspace_utils.js";
-import { FontInfo } from "../shared/obj-bin-transform.js";
 import { getFontSubstitution } from "./font_substitutions.js";
 import { getGlyphsUnicode } from "./glyphlist.js";
 import { getMetrics } from "./metrics.js";
@@ -4660,11 +4660,8 @@ class PartialEvaluator {
         if (font.renderer.hasBuiltPath(fontChar)) {
           return;
         }
-        handler.send("commonobj", [
-          glyphName,
-          "FontPath",
-          font.renderer.getPathJs(fontChar),
-        ]);
+        const buffer = FontPathInfo.write(font.renderer.getPathJs(fontChar));
+        handler.send("commonobj", [glyphName, "FontPath", buffer], [buffer]);
       } catch (reason) {
         if (evaluatorOptions.ignoreErrors) {
           warn(`buildFontPaths - ignoring ${glyphName} glyph: "${reason}".`);

src/core/font_renderer.js

@@ -770,10 +770,6 @@ class Commands {
   restore() {
     this.currentTransform = this.transformStack.pop() || [1, 0, 0, 1, 0, 0];
   }
-
-  getSVG() {
-    return this.cmds.join("");
-  }
 }
 
 class CompiledFont {
@@ -836,7 +832,7 @@ class CompiledFont {
     this.compileGlyphImpl(code, cmds, glyphId);
     cmds.add("Z");
 
-    return cmds.getSVG();
+    return cmds.cmds;
   }
 
   compileGlyphImpl() {

src/display/api.js

@@ -45,6 +45,7 @@ import {
   StatTimer,
 } from "./display_utils.js";
 import { FontFaceObject, FontLoader } from "./font_loader.js";
+import { FontInfo, FontPathInfo } from "../shared/obj-bin-transform.js";
 import {
   getDataProp,
   getFactoryUrlProp,
@@ -67,7 +68,6 @@ import { DOMCMapReaderFactory } from "display-cmap_reader_factory";
 import { DOMFilterFactory } from "./filter_factory.js";
 import { DOMStandardFontDataFactory } from "display-standard_fontdata_factory";
 import { DOMWasmFactory } from "display-wasm_factory";
-import { FontInfo } from "../shared/obj-bin-transform.js";
 import { GlobalWorkerOptions } from "./worker_options.js";
 import { Metadata } from "./metadata.js";
 import { OptionalContentConfig } from "./optional_content_config.js";
@@ -2803,6 +2803,8 @@ class WorkerTransport {
           }
           break;
         case "FontPath":
+          this.commonObjs.resolve(id, new FontPathInfo(exportedData));
+          break;
         case "Image":
         case "Pattern":
           this.commonObjs.resolve(id, exportedData);

src/display/font_loader.js

@@ -435,7 +435,7 @@ class FontFaceObject {
     } catch (ex) {
       warn(`getPathGenerator - ignoring character: "${ex}".`);
     }
-    const path = new Path2D(cmds || "");
+    const path = new Path2D(cmds?.getSVG() || "");
 
     if (!this.fontExtraProperties) {
       // Remove the raw path-string, since we don't need it anymore.

src/shared/obj-bin-transform.js

@@ -606,4 +606,79 @@ class FontInfo {
   }
 }
 
-export { CssFontInfo, FontInfo, SystemFontInfo };
+class FontPathInfo {
+  static write(path) {
+    let lengthEstimate = 0;
+    const commands = [];
+    for (const cmd of path) {
+      const code = cmd.charCodeAt(0);
+      let args = null;
+      if (code === 67 || code === 76 || code === 77) {
+        args = cmd.slice(1).split(" ");
+        lengthEstimate += 1 + args.length * 8;
+      } else if (code === 90) {
+        lengthEstimate += 1;
+      } else {
+        throw new Error(`Invalid path command: ${cmd}`);
+      }
+      commands.push({ code, args });
+    }
+
+    const buffer = new ArrayBuffer(4 + lengthEstimate);
+    const view = new DataView(buffer);
+    let offset = 0;
+
+    view.setUint32(offset, commands.length);
+    offset += 4;
+    for (const { code, args } of commands) {
+      view.setUint8(offset, code);
+      offset += 1;
+      if (args) {
+        for (const arg of args) {
+          view.setFloat64(offset, parseFloat(arg), true);
+          offset += 8;
+        }
+      }
+    }
+
+    assert(offset === buffer.byteLength, "FontPathInfo.write: Buffer overflow");
+    return buffer;
+  }
+
+  #buffer;
+
+  #view;
+
+  constructor(buffer) {
+    this.#buffer = buffer;
+    this.#view = new DataView(this.#buffer);
+  }
+
+  getSVG() {
+    const length = this.#view.getUint32(0);
+    const cmds = [];
+    let offset = 4;
+    for (let i = 0; i < length; i++) {
+      const code = String.fromCharCode(this.#view.getUint8(offset));
+      offset += 1;
+      // eslint-disable-next-line no-nested-ternary
+      const numArgs = code === "M" || code === "L" ? 2 : code === "C" ? 6 : 0;
+      let args = null;
+      if (numArgs > 0) {
+        args = [];
+        for (let j = 0; j < numArgs; j++) {
+          args.push(this.#view.getFloat64(offset, true));
+          offset += 8;
+        }
+      }
+      cmds.push(code + (args ? args.join(" ") : ""));
+    }
+    assert(
+      offset === this.#buffer.byteLength,
+      "FontPathInfo.toString: Buffer overflow"
+    );
+    return cmds.join("");
+  }
+}
+
+export { CssFontInfo, FontInfo, FontPathInfo, SystemFontInfo };

test/unit/bin_font_info_spec.js

@@ -10,7 +10,6 @@
     "app_options_spec.js",
     "autolinker_spec.js",
     "bidi_spec.js",
-    "bin_font_info_spec.js",
     "canvas_factory_spec.js",
     "cff_parser_spec.js",
     "cmap_spec.js",
@@ -33,6 +32,7 @@
     "murmurhash3_spec.js",
     "network_utils_spec.js",
     "node_stream_spec.js",
+    "obj_bin_transform_spec.js",
     "parser_spec.js",
     "pdf.image_decoders_spec.js",
     "pdf.worker_spec.js",

test/unit/clitests.json

@@ -53,7 +53,6 @@ async function initializePDFJS(callback) {
       "pdfjs-test/unit/app_options_spec.js",
       "pdfjs-test/unit/autolinker_spec.js",
       "pdfjs-test/unit/bidi_spec.js",
-      "pdfjs-test/unit/bin_font_info_spec.js",
       "pdfjs-test/unit/canvas_factory_spec.js",
       "pdfjs-test/unit/cff_parser_spec.js",
       "pdfjs-test/unit/cmap_spec.js",
@@ -76,6 +75,7 @@ async function initializePDFJS(callback) {
       "pdfjs-test/unit/murmurhash3_spec.js",
       "pdfjs-test/unit/network_spec.js",
       "pdfjs-test/unit/network_utils_spec.js",
+      "pdfjs-test/unit/obj_bin_transform_spec.js",
       "pdfjs-test/unit/parser_spec.js",
       "pdfjs-test/unit/pdf.image_decoders_spec.js",
       "pdfjs-test/unit/pdf.worker_spec.js",