Uses rAF to interrupt the operator list execution

src/display/api.js

@@ -1271,6 +1271,10 @@ var InternalRenderTask = (function InternalRenderTaskClosure() {
     this.graphicsReady = false;
     this.cancelled = false;
     this.capability = createPromiseCapability();
+    // caching this-bound methods
+    this._continueBound = this._continue.bind(this);
+    this._scheduleNextBound = this._scheduleNext.bind(this);
+    this._nextBound = this._next.bind(this);
   }
 
   InternalRenderTask.prototype = {
@@ -1309,7 +1313,7 @@ var InternalRenderTask = (function InternalRenderTaskClosure() {
     operatorListChanged: function InternalRenderTask_operatorListChanged() {
       if (!this.graphicsReady) {
         if (!this.graphicsReadyCallback) {
-          this.graphicsReadyCallback = this._continue.bind(this);
+          this.graphicsReadyCallback = this._continueBound;
         }
         return;
       }
@@ -1330,19 +1334,23 @@ var InternalRenderTask = (function InternalRenderTaskClosure() {
         return;
       }
       if (this.params.continueCallback) {
-        this.params.continueCallback(this._next.bind(this));
+        this.params.continueCallback(this._scheduleNextBound);
       } else {
-        this._next();
+        this._scheduleNext();
       }
     },
 
+    _scheduleNext: function InternalRenderTask__scheduleNext() {
+      window.requestAnimationFrame(this._nextBound);
+    },
+
     _next: function InternalRenderTask__next() {
       if (this.cancelled) {
         return;
       }
       this.operatorListIdx = this.gfx.executeOperatorList(this.operatorList,
                                         this.operatorListIdx,
-                                        this._continue.bind(this),
+                                        this._continueBound,
                                         this.stepper);
       if (this.operatorListIdx === this.operatorList.argsArray.length) {
         this.running = false;

src/display/canvas.js

@@ -746,7 +746,6 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
       var commonObjs = this.commonObjs;
       var objs = this.objs;
       var fnId;
-      var deferred = Promise.resolve();
 
       while (true) {
         if (stepper && i === stepper.nextBreakPoint) {
@@ -784,11 +783,10 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
           return i;
         }
 
-        // If the execution took longer then a certain amount of time, schedule
+        // If the execution took longer then a certain amount of time and
-        // to continue exeution after a short delay.
+        // `continueCallback` is specified, interrupt the execution.
-        // However, this is only possible if a 'continueCallback' is passed in.
         if (continueCallback && Date.now() > endTime) {
-          deferred.then(continueCallback);
+          continueCallback();
           return i;
         }
 

web/compatibility.js

@@ -564,3 +564,15 @@ if (typeof PDFJS === 'undefined') {
     console.log('Unable to create polyfill for localStorage');
   }
 })();
+
+(function checkRequestAnimationFrame() {
+  if ('requestAnimationFrame' in window) {
+    return;
+  }
+  window.requestAnimationFrame =
+    window.mozRequestAnimationFrame || window.webkitRequestAnimationFrame ||
+    window.oRequestAnimationFrame || window.msRequestAnimationFrame ||
+    (function fakeRequestAnimationFrame(callback) {
+      window.setTimeout(callback, 20);
+    });
+})();

web/viewer.js

@@ -2410,16 +2410,8 @@ window.addEventListener('afterprint', function afterPrint(evt) {
 (function animationStartedClosure() {
   // The offsetParent is not set until the pdf.js iframe or object is visible.
   // Waiting for first animation.
-  var requestAnimationFrame = window.requestAnimationFrame ||
-                              window.mozRequestAnimationFrame ||
-                              window.webkitRequestAnimationFrame ||
-                              window.oRequestAnimationFrame ||
-                              window.msRequestAnimationFrame ||
-                              function startAtOnce(callback) { callback(); };
   PDFView.animationStartedPromise = new Promise(function (resolve) {
-    requestAnimationFrame(function onAnimationFrame() {
+    window.requestAnimationFrame(resolve);
-      resolve();
-    });
   });
 })();