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web/firefox_print_service.js

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+/* Copyright 2016 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 {
+  AnnotationMode,
+  PixelsPerInch,
+  RenderingCancelledException,
+  shadow,
+} from "pdfjs-lib";
+import { getXfaHtmlForPrinting } from "./print_utils.js";
+
+// Creates a placeholder with div and canvas with right size for the page.
+function composePage(
+  pdfDocument,
+  pageNumber,
+  size,
+  printContainer,
+  printResolution,
+  optionalContentConfigPromise,
+  printAnnotationStoragePromise
+) {
+  const canvas = document.createElement("canvas");
+
+  // The size of the canvas in pixels for printing.
+  const PRINT_UNITS = printResolution / PixelsPerInch.PDF;
+  canvas.width = Math.floor(size.width * PRINT_UNITS);
+  canvas.height = Math.floor(size.height * PRINT_UNITS);
+
+  const canvasWrapper = document.createElement("div");
+  canvasWrapper.className = "printedPage";
+  canvasWrapper.append(canvas);
+  printContainer.append(canvasWrapper);
+
+  // A callback for a given page may be executed multiple times for different
+  // print operations (think of changing the print settings in the browser).
+  //
+  // Since we don't support queueing multiple render tasks for the same page
+  // (and it'd be racy anyways if painting the page is not done in one go) we
+  // keep track of the last scheduled task in order to properly cancel it before
+  // starting the next one.
+  let currentRenderTask = null;
+  canvas.mozPrintCallback = function (obj) {
+    // Printing/rendering the page.
+    const ctx = obj.context;
+
+    ctx.save();
+    ctx.fillStyle = "rgb(255, 255, 255)";
+    ctx.fillRect(0, 0, canvas.width, canvas.height);
+    ctx.restore();
+
+    let thisRenderTask = null;
+
+    Promise.all([
+      pdfDocument.getPage(pageNumber),
+      printAnnotationStoragePromise,
+    ])
+      .then(function ([pdfPage, printAnnotationStorage]) {
+        if (currentRenderTask) {
+          currentRenderTask.cancel();
+          currentRenderTask = null;
+        }
+        const renderContext = {
+          canvasContext: ctx,
+          canvas: null,
+          transform: [PRINT_UNITS, 0, 0, PRINT_UNITS, 0, 0],
+          viewport: pdfPage.getViewport({ scale: 1, rotation: size.rotation }),
+          intent: "print",
+          annotationMode: AnnotationMode.ENABLE_STORAGE,
+          optionalContentConfigPromise,
+          printAnnotationStorage,
+        };
+        currentRenderTask = thisRenderTask = pdfPage.render(renderContext);
+        return thisRenderTask.promise;
+      })
+      .then(
+        function () {
+          // Tell the printEngine that rendering this canvas/page has finished.
+          if (currentRenderTask === thisRenderTask) {
+            currentRenderTask = null;
+          }
+          obj.done();
+        },
+        function (reason) {
+          if (!(reason instanceof RenderingCancelledException)) {
+            console.error(reason);
+          }
+
+          if (currentRenderTask === thisRenderTask) {
+            currentRenderTask.cancel();
+            currentRenderTask = null;
+          }
+
+          // Tell the printEngine that rendering this canvas/page has failed.
+          // This will make the print process stop.
+          if ("abort" in obj) {
+            obj.abort();
+          } else {
+            obj.done();
+          }
+        }
+      );
+  };
+}
+
+class FirefoxPrintService {
+  constructor({
+    pdfDocument,
+    pagesOverview,
+    printContainer,
+    printResolution,
+    printAnnotationStoragePromise = null,
+  }) {
+    this.pdfDocument = pdfDocument;
+    this.pagesOverview = pagesOverview;
+    this.printContainer = printContainer;
+    this._printResolution = printResolution || 150;
+    this._optionalContentConfigPromise = pdfDocument.getOptionalContentConfig({
+      intent: "print",
+    });
+    this._printAnnotationStoragePromise =
+      printAnnotationStoragePromise || Promise.resolve();
+  }
+
+  layout() {
+    const {
+      pdfDocument,
+      pagesOverview,
+      printContainer,
+      _printResolution,
+      _optionalContentConfigPromise,
+      _printAnnotationStoragePromise,
+    } = this;
+
+    const body = document.querySelector("body");
+    body.setAttribute("data-pdfjsprinting", true);
+
+    const { width, height } = this.pagesOverview[0];
+    const hasEqualPageSizes = this.pagesOverview.every(
+      size => size.width === width && size.height === height
+    );
+    if (!hasEqualPageSizes) {
+      console.warn(
+        "Not all pages have the same size. The printed result may be incorrect!"
+      );
+    }
+
+    // Insert a @page + size rule to make sure that the page size is correctly
+    // set. Note that we assume that all pages have the same size, because
+    // variable-size pages are scaled down to the initial page size in Firefox.
+    this.pageStyleSheet = document.createElement("style");
+    this.pageStyleSheet.textContent = `@page { size: ${width}pt ${height}pt;}`;
+    body.append(this.pageStyleSheet);
+
+    if (pdfDocument.isPureXfa) {
+      getXfaHtmlForPrinting(printContainer, pdfDocument);
+      return;
+    }
+
+    for (let i = 0, ii = pagesOverview.length; i < ii; ++i) {
+      composePage(
+        pdfDocument,
+        /* pageNumber = */ i + 1,
+        pagesOverview[i],
+        printContainer,
+        _printResolution,
+        _optionalContentConfigPromise,
+        _printAnnotationStoragePromise
+      );
+    }
+  }
+
+  destroy() {
+    this.printContainer.textContent = "";
+
+    const body = document.querySelector("body");
+    body.removeAttribute("data-pdfjsprinting");
+
+    if (this.pageStyleSheet) {
+      this.pageStyleSheet.remove();
+      this.pageStyleSheet = null;
+    }
+  }
+}
+
+/**
+ * @implements {IPDFPrintServiceFactory}
+ */
+class PDFPrintServiceFactory {
+  static get supportsPrinting() {
+    const canvas = document.createElement("canvas");
+    return shadow(this, "supportsPrinting", "mozPrintCallback" in canvas);
+  }
+
+  static createPrintService(params) {
+    return new FirefoxPrintService(params);
+  }
+}
+
+export { PDFPrintServiceFactory };