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web/pdf_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.
+ */
+
+// eslint-disable-next-line max-len
+/** @typedef {import("./interfaces.js").IPDFPrintServiceFactory} IPDFPrintServiceFactory */
+
+import {
+  AnnotationMode,
+  PixelsPerInch,
+  RenderingCancelledException,
+  shadow,
+} from "pdfjs-lib";
+import { getXfaHtmlForPrinting } from "./print_utils.js";
+
+let activeService = null;
+let dialog = null;
+let overlayManager = null;
+let viewerApp = { initialized: false };
+
+// Renders the page to the canvas of the given print service, and returns
+// the suggested dimensions of the output page.
+function renderPage(
+  activeServiceOnEntry,
+  pdfDocument,
+  pageNumber,
+  size,
+  printResolution,
+  optionalContentConfigPromise,
+  printAnnotationStoragePromise
+) {
+  const scratchCanvas = activeService.scratchCanvas;
+
+  // The size of the canvas in pixels for printing.
+  const PRINT_UNITS = printResolution / PixelsPerInch.PDF;
+  scratchCanvas.width = Math.floor(size.width * PRINT_UNITS);
+  scratchCanvas.height = Math.floor(size.height * PRINT_UNITS);
+
+  const ctx = scratchCanvas.getContext("2d");
+  ctx.save();
+  ctx.fillStyle = "rgb(255, 255, 255)";
+  ctx.fillRect(0, 0, scratchCanvas.width, scratchCanvas.height);
+  ctx.restore();
+
+  return Promise.all([
+    pdfDocument.getPage(pageNumber),
+    printAnnotationStoragePromise,
+  ]).then(function ([pdfPage, printAnnotationStorage]) {
+    const renderContext = {
+      canvas: scratchCanvas,
+      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,
+    };
+    const renderTask = pdfPage.render(renderContext);
+
+    return renderTask.promise.catch(reason => {
+      if (!(reason instanceof RenderingCancelledException)) {
+        console.error(reason);
+      }
+      throw reason;
+    });
+  });
+}
+
+class PDFPrintService {
+  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();
+    this.currentPage = -1;
+    // The temporary canvas where renderPage paints one page at a time.
+    this.scratchCanvas = document.createElement("canvas");
+  }
+
+  layout() {
+    this.throwIfInactive();
+
+    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 not supported yet (e.g. in Chrome & Firefox).
+    // TODO(robwu): Use named pages when size calculation bugs get resolved
+    // (e.g. https://crbug.com/355116) AND when support for named pages is
+    // added (http://www.w3.org/TR/css3-page/#using-named-pages).
+    // In browsers where @page + size is not supported, the next stylesheet
+    // will be ignored and the user has to select the correct paper size in
+    // the UI if wanted.
+    this.pageStyleSheet = document.createElement("style");
+    this.pageStyleSheet.textContent = `@page { size: ${width}pt ${height}pt;}`;
+    body.append(this.pageStyleSheet);
+  }
+
+  destroy() {
+    if (activeService !== this) {
+      // |activeService| cannot be replaced without calling destroy() first,
+      // so if it differs then an external consumer has a stale reference to us.
+      return;
+    }
+    this.printContainer.textContent = "";
+
+    const body = document.querySelector("body");
+    body.removeAttribute("data-pdfjsprinting");
+
+    if (this.pageStyleSheet) {
+      this.pageStyleSheet.remove();
+      this.pageStyleSheet = null;
+    }
+    this.scratchCanvas.width = this.scratchCanvas.height = 0;
+    this.scratchCanvas = null;
+    activeService = null;
+    ensureOverlay().then(function () {
+      overlayManager.closeIfActive(dialog);
+    });
+  }
+
+  renderPages() {
+    if (this.pdfDocument.isPureXfa) {
+      getXfaHtmlForPrinting(this.printContainer, this.pdfDocument);
+      return Promise.resolve();
+    }
+
+    const pageCount = this.pagesOverview.length;
+    const renderNextPage = (resolve, reject) => {
+      this.throwIfInactive();
+      if (++this.currentPage >= pageCount) {
+        renderProgress(pageCount, pageCount);
+        resolve();
+        return;
+      }
+      const index = this.currentPage;
+      renderProgress(index, pageCount);
+      renderPage(
+        this,
+        this.pdfDocument,
+        /* pageNumber = */ index + 1,
+        this.pagesOverview[index],
+        this._printResolution,
+        this._optionalContentConfigPromise,
+        this._printAnnotationStoragePromise
+      )
+        .then(this.useRenderedPage.bind(this))
+        .then(function () {
+          renderNextPage(resolve, reject);
+        }, reject);
+    };
+    return new Promise(renderNextPage);
+  }
+
+  useRenderedPage() {
+    this.throwIfInactive();
+    const img = document.createElement("img");
+    this.scratchCanvas.toBlob(blob => {
+      img.src = URL.createObjectURL(blob);
+    });
+
+    const wrapper = document.createElement("div");
+    wrapper.className = "printedPage";
+    wrapper.append(img);
+    this.printContainer.append(wrapper);
+
+    const { promise, resolve, reject } = Promise.withResolvers();
+    img.onload = resolve;
+    img.onerror = reject;
+
+    promise
+      .catch(() => {
+        // Avoid "Uncaught promise" messages in the console.
+      })
+      .then(() => {
+        URL.revokeObjectURL(img.src);
+      });
+    return promise;
+  }
+
+  performPrint() {
+    this.throwIfInactive();
+    return new Promise(resolve => {
+      // Push window.print in the macrotask queue to avoid being affected by
+      // the deprecation of running print() code in a microtask, see
+      // https://github.com/mozilla/pdf.js/issues/7547.
+      setTimeout(() => {
+        if (!this.active) {
+          resolve();
+          return;
+        }
+        print.call(window);
+        // Delay promise resolution in case print() was not synchronous.
+        setTimeout(resolve, 20); // Tidy-up.
+      }, 0);
+    });
+  }
+
+  get active() {
+    return this === activeService;
+  }
+
+  throwIfInactive() {
+    if (!this.active) {
+      throw new Error("This print request was cancelled or completed.");
+    }
+  }
+}
+
+const print = window.print;
+window.print = function () {
+  if (activeService) {
+    console.warn("Ignored window.print() because of a pending print job.");
+    return;
+  }
+  ensureOverlay().then(function () {
+    if (activeService) {
+      overlayManager.open(dialog);
+    }
+  });
+
+  try {
+    dispatchEvent("beforeprint");
+  } finally {
+    if (!activeService) {
+      if (typeof PDFJSDev !== "undefined" && PDFJSDev.test("TESTING")) {
+        // eslint-disable-next-line no-unsafe-finally
+        throw new Error("window.print() is not supported");
+      }
+      console.error("Expected print service to be initialized.");
+      ensureOverlay().then(function () {
+        overlayManager.closeIfActive(dialog);
+      });
+    } else {
+      const activeServiceOnEntry = activeService;
+      activeService
+        .renderPages()
+        .then(() => activeServiceOnEntry.performPrint())
+        .catch(() => {
+          // Ignore any error messages.
+        })
+        .then(() => {
+          // aborts acts on the "active" print request, so we need to check
+          // whether the print request (activeServiceOnEntry) is still active.
+          // Without the check, an unrelated print request (created after
+          // aborting this print request while the pages were being generated)
+          // would be aborted.
+          if (activeServiceOnEntry.active) {
+            abort();
+          }
+        });
+    }
+  }
+};
+
+function dispatchEvent(eventType) {
+  const event = new CustomEvent(eventType, {
+    bubbles: false,
+    cancelable: false,
+    detail: "custom",
+  });
+  window.dispatchEvent(event);
+}
+
+function abort() {
+  if (activeService) {
+    activeService.destroy();
+    dispatchEvent("afterprint");
+  }
+}
+
+function renderProgress(index, total) {
+  if (typeof PDFJSDev === "undefined" && window.isGECKOVIEW) {
+    return;
+  }
+  dialog ||= document.getElementById("printServiceDialog");
+  const progress = Math.round((100 * index) / total);
+  const progressBar = dialog.querySelector("progress");
+  const progressPerc = dialog.querySelector(".relative-progress");
+  progressBar.value = progress;
+  progressPerc.setAttribute("data-l10n-args", JSON.stringify({ progress }));
+}
+
+window.addEventListener(
+  "keydown",
+  function (event) {
+    // Intercept Cmd/Ctrl + P in all browsers.
+    // Also intercept Cmd/Ctrl + Shift + P in Chrome and Opera
+    if (
+      event.keyCode === /* P= */ 80 &&
+      (event.ctrlKey || event.metaKey) &&
+      !event.altKey &&
+      (!event.shiftKey || window.chrome || window.opera)
+    ) {
+      window.print();
+
+      event.preventDefault();
+      event.stopImmediatePropagation();
+    }
+  },
+  true
+);
+
+if ("onbeforeprint" in window) {
+  // Do not propagate before/afterprint events when they are not triggered
+  // from within this polyfill. (FF / Chrome 63+).
+  const stopPropagationIfNeeded = function (event) {
+    if (event.detail !== "custom") {
+      event.stopImmediatePropagation();
+    }
+  };
+  window.addEventListener("beforeprint", stopPropagationIfNeeded);
+  window.addEventListener("afterprint", stopPropagationIfNeeded);
+}
+
+let overlayPromise;
+function ensureOverlay() {
+  if (typeof PDFJSDev === "undefined" && window.isGECKOVIEW) {
+    return Promise.reject(
+      new Error("ensureOverlay not implemented in GECKOVIEW development mode.")
+    );
+  }
+  if (!overlayPromise) {
+    overlayManager = viewerApp.overlayManager;
+    if (!overlayManager) {
+      throw new Error("The overlay manager has not yet been initialized.");
+    }
+    dialog ||= document.getElementById("printServiceDialog");
+
+    overlayPromise = overlayManager.register(
+      dialog,
+      /* canForceClose = */ true
+    );
+
+    document.getElementById("printCancel").onclick = abort;
+    dialog.addEventListener("close", abort);
+  }
+  return overlayPromise;
+}
+
+/**
+ * @implements {IPDFPrintServiceFactory}
+ */
+class PDFPrintServiceFactory {
+  static initGlobals(app) {
+    viewerApp = app;
+  }
+
+  static get supportsPrinting() {
+    return shadow(this, "supportsPrinting", true);
+  }
+
+  static createPrintService(params) {
+    if (activeService) {
+      throw new Error("The print service is created and active.");
+    }
+    return (activeService = new PDFPrintService(params));
+  }
+}
+
+export { PDFPrintServiceFactory };