Merge pull request #11646 from Snuffleupagus/_setDocumentAllowFetchPages

Ensure that automatic printing still works when the viewer and/or its pages are hidden (bug 1618621, bug 1618955)

web/base_viewer.js

@@ -391,9 +391,30 @@ class BaseViewer {
   /**
    * @private
    */
-  get _setDocumentViewerElement() {
+  get _viewerElement() {
     // In most viewers, e.g. `PDFViewer`, this should return `this.viewer`.
-    throw new Error("Not implemented: _setDocumentViewerElement");
+    throw new Error("Not implemented: _viewerElement");
+  }
+
+  /**
+   * @private
+   */
+  _onePageRenderedOrForceFetch() {
+    // Unless the viewer *and* its pages are visible, rendering won't start and
+    // `this._onePageRenderedCapability` thus won't be resolved.
+    // To ensure that automatic printing, on document load, still works even in
+    // those cases we force-allow fetching of all pages when:
+    //  - The viewer is hidden in the DOM, e.g. in a `display: none` <iframe>
+    //    element; fixes bug 1618621.
+    //  - The viewer is visible, but none of the pages are (e.g. if the
+    //    viewer is very small); fixes bug 1618955.
+    if (
+      !this.container.offsetParent ||
+      this._getVisiblePages().views.length === 0
+    ) {
+      return Promise.resolve();
+    }
+    return this._onePageRenderedCapability.promise;
   }
 
   /**
@@ -458,7 +479,7 @@ class BaseViewer {
 
         for (let pageNum = 1; pageNum <= pagesCount; ++pageNum) {
           const pageView = new PDFPageView({
-            container: this._setDocumentViewerElement,
+            container: this._viewerElement,
             eventBus: this.eventBus,
             id: pageNum,
             scale,
@@ -492,7 +513,7 @@ class BaseViewer {
         // Fetch all the pages since the viewport is needed before printing
         // starts to create the correct size canvas. Wait until one page is
         // rendered so we don't tie up too many resources early on.
-        this._onePageRenderedCapability.promise.then(() => {
+        this._onePageRenderedOrForceFetch().then(() => {
           if (this.findController) {
             this.findController.setDocument(pdfDocument); // Enable searching.
           }

web/pdf_single_page_viewer.js

@@ -27,12 +27,12 @@ class PDFSinglePageViewer extends BaseViewer {
     });
   }
 
-  get _setDocumentViewerElement() {
+  get _viewerElement() {
     // Since we only want to display *one* page at a time when using the
     // `PDFSinglePageViewer`, we cannot append them to the `viewer` DOM element.
     // Instead, they are placed in a `DocumentFragment`, and only the current
     // page is displayed in the viewer (refer to `this._ensurePageViewVisible`).
-    return shadow(this, "_setDocumentViewerElement", this._shadowViewer);
+    return shadow(this, "_viewerElement", this._shadowViewer);
   }
 
   _resetView() {

web/pdf_viewer.js

@@ -17,8 +17,8 @@ import { BaseViewer } from "./base_viewer.js";
 import { shadow } from "pdfjs-lib";
 
 class PDFViewer extends BaseViewer {
-  get _setDocumentViewerElement() {
-    return shadow(this, "_setDocumentViewerElement", this.viewer);
+  get _viewerElement() {
+    return shadow(this, "_viewerElement", this.viewer);
   }
 
   _scrollIntoView({ pageDiv, pageSpot = null, pageNumber = null }) {

web/ui_utils.js

@@ -229,7 +229,7 @@ function binarySearchFirstItem(items, condition) {
   let minIndex = 0;
   let maxIndex = items.length - 1;
 
-  if (items.length === 0 || !condition(items[maxIndex])) {
+  if (maxIndex < 0 || !condition(items[maxIndex])) {
     return items.length;
   }
   if (condition(items[minIndex])) {