[api-minor] Use the NodeCanvasFactory/NodeCMapReaderFactory classes as defaults in Node.js environments (issue 11900)

This moves, and slightly simplifies, code that's currently residing in the unit-test utils into the actual library, such that it's bundled with `GENERIC`-builds and used in e.g. the API-code.

As an added bonus, this also brings out-of-the-box support for CMaps in e.g. the Node.js examples.

test/unit/api_spec.js

@@ -16,7 +16,6 @@
 import {
   buildGetDocumentParams,
   DOMFileReaderFactory,
-  NodeCanvasFactory,
   NodeFileReaderFactory,
   TEST_PDFS_PATH,
 } from "./test_utils.js";
@@ -49,6 +48,7 @@ import { GlobalImageCache } from "../../src/core/image_utils.js";
 import { GlobalWorkerOptions } from "../../src/display/worker_options.js";
 import { isNodeJS } from "../../src/shared/is_node.js";
 import { Metadata } from "../../src/display/metadata.js";
+import { NodeCanvasFactory } from "../../src/display/node_utils.js";
 
 describe("api", function () {
   const basicApiFileName = "basicapi.pdf";

test/unit/cmap_spec.js

@@ -17,7 +17,7 @@ import { CMap, CMapFactory, IdentityCMap } from "../../src/core/cmap.js";
 import { DOMCMapReaderFactory } from "../../src/display/display_utils.js";
 import { isNodeJS } from "../../src/shared/is_node.js";
 import { Name } from "../../src/core/primitives.js";
-import { NodeCMapReaderFactory } from "./test_utils.js";
+import { NodeCMapReaderFactory } from "../../src/display/node_utils.js";
 import { StringStream } from "../../src/core/stream.js";
 
 var cMapUrl = {

test/unit/custom_spec.js

@@ -13,10 +13,11 @@
  * limitations under the License.
  */
 
-import { buildGetDocumentParams, NodeCanvasFactory } from "./test_utils.js";
+import { buildGetDocumentParams } from "./test_utils.js";
 import { DOMCanvasFactory } from "../../src/display/display_utils.js";
 import { getDocument } from "../../src/display/api.js";
 import { isNodeJS } from "../../src/shared/is_node.js";
+import { NodeCanvasFactory } from "../../src/display/node_utils.js";
 
 function getTopLeftPixel(canvasContext) {
   const imgData = canvasContext.getImageData(0, 0, 1, 1);

test/unit/test_utils.js

@@ -13,7 +13,7 @@
  * limitations under the License.
  */
 
-import { assert, CMapCompressionType } from "../../src/shared/util.js";
+import { assert } from "../../src/shared/util.js";
 import { isNodeJS } from "../../src/shared/is_node.js";
 import { isRef } from "../../src/core/primitives.js";
 import { Page } from "../../src/core/document.js";
@@ -62,77 +62,6 @@ function buildGetDocumentParams(filename, options) {
   return params;
 }
 
-class NodeCanvasFactory {
-  create(width, height) {
-    assert(width > 0 && height > 0, "Invalid canvas size");
-
-    const Canvas = require("canvas");
-    const canvas = Canvas.createCanvas(width, height);
-    return {
-      canvas,
-      context: canvas.getContext("2d"),
-    };
-  }
-
-  reset(canvasAndContext, width, height) {
-    assert(canvasAndContext.canvas, "Canvas is not specified");
-    assert(width > 0 && height > 0, "Invalid canvas size");
-
-    canvasAndContext.canvas.width = width;
-    canvasAndContext.canvas.height = height;
-  }
-
-  destroy(canvasAndContext) {
-    assert(canvasAndContext.canvas, "Canvas is not specified");
-
-    // Zeroing the width and height cause Firefox to release graphics
-    // resources immediately, which can greatly reduce memory consumption.
-    canvasAndContext.canvas.width = 0;
-    canvasAndContext.canvas.height = 0;
-    canvasAndContext.canvas = null;
-    canvasAndContext.context = null;
-  }
-}
-
-class NodeCMapReaderFactory {
-  constructor({ baseUrl = null, isCompressed = false }) {
-    this.baseUrl = baseUrl;
-    this.isCompressed = isCompressed;
-  }
-
-  async fetch({ name }) {
-    if (!this.baseUrl) {
-      throw new Error(
-        'The CMap "baseUrl" parameter must be specified, ensure that ' +
-          'the "cMapUrl" and "cMapPacked" API parameters are provided.'
-      );
-    }
-    if (!name) {
-      throw new Error("CMap name must be specified.");
-    }
-    const url = this.baseUrl + name + (this.isCompressed ? ".bcmap" : "");
-    const compressionType = this.isCompressed
-      ? CMapCompressionType.BINARY
-      : CMapCompressionType.NONE;
-
-    return new Promise((resolve, reject) => {
-      const fs = require("fs");
-      fs.readFile(url, (error, data) => {
-        if (error || !data) {
-          reject(new Error(error));
-          return;
-        }
-        resolve({ cMapData: new Uint8Array(data), compressionType });
-      });
-    }).catch(reason => {
-      throw new Error(
-        `Unable to load ${this.isCompressed ? "binary " : ""}` +
-          `CMap at: ${url}`
-      );
-    });
-  }
-}
-
 class XRefMock {
   constructor(array) {
     this._map = Object.create(null);
@@ -186,8 +115,6 @@ function isEmptyObj(obj) {
 export {
   DOMFileReaderFactory,
   NodeFileReaderFactory,
-  NodeCanvasFactory,
-  NodeCMapReaderFactory,
   XRefMock,
   buildGetDocumentParams,
   TEST_PDFS_PATH,