123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213 |
- import { RenderingCancelledException } from "pdfjs-lib";
- import { RenderingStates } from "./ui_utils.js";
- const CLEANUP_TIMEOUT = 30000;
- class PDFRenderingQueue {
- constructor() {
- this.pdfViewer = null;
- this.pdfThumbnailViewer = null;
- this.onIdle = null;
- this.highestPriorityPage = null;
-
- this.idleTimeout = null;
- this.printing = false;
- this.isThumbnailViewEnabled = false;
- }
-
- setViewer(pdfViewer) {
- this.pdfViewer = pdfViewer;
- }
-
- setThumbnailViewer(pdfThumbnailViewer) {
- this.pdfThumbnailViewer = pdfThumbnailViewer;
- }
-
- isHighestPriority(view) {
- return this.highestPriorityPage === view.renderingId;
- }
-
- hasViewer() {
- return !!this.pdfViewer;
- }
-
- renderHighestPriority(currentlyVisiblePages) {
- if (this.idleTimeout) {
- clearTimeout(this.idleTimeout);
- this.idleTimeout = null;
- }
-
- if (this.pdfViewer.forceRendering(currentlyVisiblePages)) {
- return;
- }
-
- if (
- this.isThumbnailViewEnabled &&
- this.pdfThumbnailViewer?.forceRendering()
- ) {
- return;
- }
- if (this.printing) {
-
- return;
- }
- if (this.onIdle) {
- this.idleTimeout = setTimeout(this.onIdle.bind(this), CLEANUP_TIMEOUT);
- }
- }
-
- getHighestPriority(visible, views, scrolledDown, preRenderExtra = false) {
-
- const visibleViews = visible.views,
- numVisible = visibleViews.length;
- if (numVisible === 0) {
- return null;
- }
- for (let i = 0; i < numVisible; i++) {
- const view = visibleViews[i].view;
- if (!this.isViewFinished(view)) {
- return view;
- }
- }
- const firstId = visible.first.id,
- lastId = visible.last.id;
-
-
- if (lastId - firstId + 1 > numVisible) {
- const visibleIds = visible.ids;
- for (let i = 1, ii = lastId - firstId; i < ii; i++) {
- const holeId = scrolledDown ? firstId + i : lastId - i;
- if (visibleIds.has(holeId)) {
- continue;
- }
- const holeView = views[holeId - 1];
- if (!this.isViewFinished(holeView)) {
- return holeView;
- }
- }
- }
-
-
- let preRenderIndex = scrolledDown ? lastId : firstId - 2;
- let preRenderView = views[preRenderIndex];
- if (preRenderView && !this.isViewFinished(preRenderView)) {
- return preRenderView;
- }
- if (preRenderExtra) {
- preRenderIndex += scrolledDown ? 1 : -1;
- preRenderView = views[preRenderIndex];
- if (preRenderView && !this.isViewFinished(preRenderView)) {
- return preRenderView;
- }
- }
-
- return null;
- }
-
- isViewFinished(view) {
- return view.renderingState === RenderingStates.FINISHED;
- }
-
- renderView(view) {
- switch (view.renderingState) {
- case RenderingStates.FINISHED:
- return false;
- case RenderingStates.PAUSED:
- this.highestPriorityPage = view.renderingId;
- view.resume();
- break;
- case RenderingStates.RUNNING:
- this.highestPriorityPage = view.renderingId;
- break;
- case RenderingStates.INITIAL:
- this.highestPriorityPage = view.renderingId;
- view
- .draw()
- .finally(() => {
- this.renderHighestPriority();
- })
- .catch(reason => {
- if (reason instanceof RenderingCancelledException) {
- return;
- }
- console.error(`renderView: "${reason}"`);
- });
- break;
- }
- return true;
- }
- }
- export { PDFRenderingQueue };
|