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examples/node/pdf2png/pdf2png.mjs

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+/* Copyright 2017 Mozilla Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import fs from "fs";
+import { getDocument } from "pdfjs-dist/legacy/build/pdf.mjs";
+
+// Some PDFs need external cmaps.
+const CMAP_URL = "../../../node_modules/pdfjs-dist/cmaps/";
+const CMAP_PACKED = true;
+
+// Where the standard fonts are located.
+const STANDARD_FONT_DATA_URL =
+  "../../../node_modules/pdfjs-dist/standard_fonts/";
+
+// Loading file from file system into typed array.
+const pdfPath =
+  process.argv[2] || "../../../web/compressed.tracemonkey-pldi-09.pdf";
+const data = new Uint8Array(fs.readFileSync(pdfPath));
+
+// Load the PDF file.
+const loadingTask = getDocument({
+  data,
+  cMapUrl: CMAP_URL,
+  cMapPacked: CMAP_PACKED,
+  standardFontDataUrl: STANDARD_FONT_DATA_URL,
+});
+
+try {
+  const pdfDocument = await loadingTask.promise;
+  console.log("# PDF document loaded.");
+  // Get the first page.
+  const page = await pdfDocument.getPage(1);
+  // Render the page on a Node canvas with 100% scale.
+  const canvasFactory = pdfDocument.canvasFactory;
+  const viewport = page.getViewport({ scale: 1.0 });
+  const canvasAndContext = canvasFactory.create(
+    viewport.width,
+    viewport.height
+  );
+  const renderContext = {
+    canvasContext: canvasAndContext.context,
+    viewport,
+  };
+
+  const renderTask = page.render(renderContext);
+  await renderTask.promise;
+  // Convert the canvas to an image buffer.
+  const image = canvasAndContext.canvas.toBuffer("image/png");
+  fs.writeFile("output.png", image, function (error) {
+    if (error) {
+      console.error("Error: " + error);
+    } else {
+      console.log("Finished converting first page of PDF file to a PNG image.");
+    }
+  });
+  // Release page resources.
+  page.cleanup();
+} catch (reason) {
+  console.log(reason);
+}