Improve scrolling performance in OOP PDF

chrome/test/data/pdf/viewport_test.js

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 function MockWindow(width, height) {
   this.innerWidth = width;
   this.innerHeight = height;
   this.addEventListener = function(e, f) {
     if (e == 'scroll')
       this.scrollCallback = f;
@@ skipping 50 matching lines @@
   this.reset = function() {
     this.width = 0;
     this.height = 0;
     this.pageDimensions = [];
   };
 }
 
 var tests = [
   function testDocumentNeedsScrollbars() {
     var viewport = new Viewport(new MockWindow(100, 100), new MockSizer(),
-                                function() {}, 0);
+                                function() {}, function() {}, function() {}, 0);
     var scrollbars;
 
     viewport.setDocumentDimensions(new MockDocumentDimensions(90, 90));
     scrollbars = viewport.documentNeedsScrollbars_(1);
     chrome.test.assertFalse(scrollbars.vertical);
     chrome.test.assertFalse(scrollbars.horizontal);
 
     viewport.setDocumentDimensions(new MockDocumentDimensions(100, 100));
     scrollbars = viewport.documentNeedsScrollbars_(1);
     chrome.test.assertFalse(scrollbars.vertical);
@@ skipping 18 matching lines @@
     scrollbars = viewport.documentNeedsScrollbars_(0.5);
     chrome.test.assertTrue(scrollbars.vertical);
     chrome.test.assertFalse(scrollbars.horizontal);
     chrome.test.succeed();
   },
 
   function testSetZoom() {
     var mockWindow = new MockWindow(100, 100);
     var mockSizer = new MockSizer();
     var mockCallback = new MockViewportChangedCallback();
-    var viewport = new Viewport(mockWindow, mockSizer,
-                                mockCallback.callback, 0);
+    var viewport = new Viewport(mockWindow, mockSizer, mockCallback.callback,
+                                function() {}, function() {}, 0);
 
     // Test setting the zoom without the document dimensions set. The sizer
     // shouldn't change size.
     mockCallback.reset();
-    viewport.setZoom_(0.5);
+    viewport.setZoomForTest_(0.5);
     chrome.test.assertEq(0.5, viewport.zoom);
     chrome.test.assertTrue(mockCallback.wasCalled);
     chrome.test.assertEq('0px', mockSizer.style.width);
     chrome.test.assertEq('0px', mockSizer.style.height);
     chrome.test.assertEq(0, mockWindow.pageXOffset);
     chrome.test.assertEq(0, mockWindow.pageYOffset);
 
-    viewport.setZoom_(1);
+    viewport.setZoomForTest_(1);
     viewport.setDocumentDimensions(new MockDocumentDimensions(200, 200));
 
     // Test zooming out.
     mockCallback.reset();
-    viewport.setZoom_(0.5);
+    viewport.setZoomForTest_(0.5);
     chrome.test.assertEq(0.5, viewport.zoom);
     chrome.test.assertTrue(mockCallback.wasCalled);
     chrome.test.assertEq('100px', mockSizer.style.width);
     chrome.test.assertEq('100px', mockSizer.style.height);
 
     // Test zooming in.
     mockCallback.reset();
-    viewport.setZoom_(2);
+    viewport.setZoomForTest_(2);
     chrome.test.assertEq(2, viewport.zoom);
     chrome.test.assertTrue(mockCallback.wasCalled);
     chrome.test.assertEq('400px', mockSizer.style.width);
     chrome.test.assertEq('400px', mockSizer.style.height);
 
     // Test that the scroll position scales correctly. It scales relative to the
     // center of the page.
-    viewport.setZoom_(1);
+    viewport.setZoomForTest_(1);
     mockWindow.pageXOffset = 50;
     mockWindow.pageYOffset = 50;
-    viewport.setZoom_(2);
+    viewport.setZoomForTest_(2);
     chrome.test.assertEq('400px', mockSizer.style.width);
     chrome.test.assertEq('400px', mockSizer.style.height);
     chrome.test.assertEq(150, mockWindow.pageXOffset);
     chrome.test.assertEq(150, mockWindow.pageYOffset);
     chrome.test.succeed();
   },
 
   function testGetMostVisiblePage() {
     var mockWindow = new MockWindow(100, 100);
-    var viewport = new Viewport(mockWindow, new MockSizer(), function() {}, 0);
+    var viewport = new Viewport(mockWindow, new MockSizer(), function() {},
+                                function() {}, function() {}, 0);
 
     var documentDimensions = new MockDocumentDimensions(100, 100);
     documentDimensions.addPage(100, 100);
     documentDimensions.addPage(150, 100);
     documentDimensions.addPage(100, 200);
     viewport.setDocumentDimensions(documentDimensions);
-    viewport.setZoom_(1);
+    viewport.setZoomForTest_(1);
 
     // Scrolled to the start of the first page.
     mockWindow.scrollTo(0, 0);
     chrome.test.assertEq(0, viewport.getMostVisiblePage());
 
     // Scrolled to the start of the second page.
     mockWindow.scrollTo(0, 100);
     chrome.test.assertEq(1, viewport.getMostVisiblePage());
 
     // Scrolled half way through the first page.
     mockWindow.scrollTo(0, 50);
     chrome.test.assertEq(0, viewport.getMostVisiblePage());
 
     // Scrolled just over half way through the first page.
     mockWindow.scrollTo(0, 51);
     chrome.test.assertEq(1, viewport.getMostVisiblePage());
 
     // Scrolled most of the way through the second page.
     mockWindow.scrollTo(0, 180);
     chrome.test.assertEq(2, viewport.getMostVisiblePage());
 
     // Scrolled just over half way through the first page with 2x zoom.
-    viewport.setZoom_(2);
+    viewport.setZoomForTest_(2);
     mockWindow.scrollTo(0, 151);
     chrome.test.assertEq(1, viewport.getMostVisiblePage());
     chrome.test.succeed();
   },
 
   function testFitToWidth() {
     var mockWindow = new MockWindow(100, 100);
     var mockSizer = new MockSizer();
     var mockCallback = new MockViewportChangedCallback();
-    var viewport = new Viewport(mockWindow, mockSizer,
-                                mockCallback.callback, 0);
+    var viewport = new Viewport(mockWindow, mockSizer, mockCallback.callback,
+                                function() {}, function() {}, 0);
     var documentDimensions = new MockDocumentDimensions();
 
     // Test with a document width which matches the window width.
     documentDimensions.addPage(100, 100);
     viewport.setDocumentDimensions(documentDimensions);
-    viewport.setZoom_(0.1);
+    viewport.setZoomForTest_(0.1);
     mockCallback.reset();
     viewport.fitToWidth();
     chrome.test.assertTrue(mockCallback.wasCalled);
     chrome.test.assertEq('100px', mockSizer.style.width);
     chrome.test.assertEq(1, viewport.zoom);
 
     // Test with a document width which is twice the size of the window width.
     documentDimensions.reset();
     documentDimensions.addPage(200, 100);
     viewport.setDocumentDimensions(documentDimensions);
@@ skipping 11 matching lines @@
     viewport.fitToWidth();
     chrome.test.assertTrue(mockCallback.wasCalled);
     chrome.test.assertEq('100px', mockSizer.style.width);
     chrome.test.assertEq(2, viewport.zoom);
 
     // Test that the scroll position stays the same relative to the page after
     // fit to page is called.
     documentDimensions.reset();
     documentDimensions.addPage(50, 400);
     viewport.setDocumentDimensions(documentDimensions);
-    viewport.setZoom_(1);
+    viewport.setZoomForTest_(1);
     mockWindow.scrollTo(0, 100);
     mockCallback.reset();
     viewport.fitToWidth();
     chrome.test.assertTrue(mockCallback.wasCalled);
     chrome.test.assertEq(2, viewport.zoom);
     chrome.test.assertEq(0, viewport.position.x);
     chrome.test.assertEq(200, viewport.position.y);
 
     // Test fitting works with scrollbars. The page will need to be zoomed to
     // fit to width, which will cause the page height to span outside of the
     // viewport, triggering 15px scrollbars to be shown.
-    viewport = new Viewport(mockWindow, mockSizer,
-                            mockCallback.callback, 15);
+    viewport = new Viewport(mockWindow, mockSizer, mockCallback.callback,
+                            function() {}, function() {}, 15);
     documentDimensions.reset();
     documentDimensions.addPage(50, 100);
     viewport.setDocumentDimensions(documentDimensions);
     mockCallback.reset();
     viewport.fitToWidth();
     chrome.test.assertTrue(mockCallback.wasCalled);
     chrome.test.assertEq('85px', mockSizer.style.width);
     chrome.test.assertEq(1.7, viewport.zoom);
     chrome.test.succeed();
   },
 
   function testFitToPage() {
     var mockWindow = new MockWindow(100, 100);
     var mockSizer = new MockSizer();
     var mockCallback = new MockViewportChangedCallback();
-    var viewport = new Viewport(mockWindow, mockSizer,
-                                mockCallback.callback, 0);
+    var viewport = new Viewport(mockWindow, mockSizer, mockCallback.callback,
+                                function() {}, function() {}, 0);
     var documentDimensions = new MockDocumentDimensions();
 
     // Test with a page size which matches the window size.
     documentDimensions.addPage(100, 100);
     viewport.setDocumentDimensions(documentDimensions);
-    viewport.setZoom_(0.1);
+    viewport.setZoomForTest_(0.1);
     mockCallback.reset();
     viewport.fitToPage();
     chrome.test.assertTrue(mockCallback.wasCalled);
     chrome.test.assertEq('100px', mockSizer.style.width);
     chrome.test.assertEq('100px', mockSizer.style.height);
     chrome.test.assertEq(1, viewport.zoom);
 
     // Test with a page size whose width is larger than its height.
     documentDimensions.reset();
     documentDimensions.addPage(200, 100);
@@ skipping 15 matching lines @@
     chrome.test.assertEq('50px', mockSizer.style.width);
     chrome.test.assertEq('100px', mockSizer.style.height);
     chrome.test.assertEq(0.5, viewport.zoom);
 
     // Test that when there are multiple pages the most visible page is sized
     // to.
     documentDimensions.reset();
     documentDimensions.addPage(200, 100);
     documentDimensions.addPage(100, 400);
     viewport.setDocumentDimensions(documentDimensions);
-    viewport.setZoom_(1);
+    viewport.setZoomForTest_(1);
     mockWindow.scrollTo(0, 0);
     mockCallback.reset();
     viewport.fitToPage();
     chrome.test.assertTrue(mockCallback.wasCalled);
     chrome.test.assertEq('100px', mockSizer.style.width);
     chrome.test.assertEq('250px', mockSizer.style.height);
     chrome.test.assertEq(0.5, viewport.zoom);
-    viewport.setZoom_(1);
+    viewport.setZoomForTest_(1);
     mockWindow.scrollTo(0, 100);
     mockCallback.reset();
     viewport.fitToPage();
     chrome.test.assertTrue(mockCallback.wasCalled);
     chrome.test.assertEq('50px', mockSizer.style.width);
     chrome.test.assertEq('125px', mockSizer.style.height);
     chrome.test.assertEq(0.25, viewport.zoom);
 
     // Test that the top of the most visible page is scrolled to.
     documentDimensions.reset();
     documentDimensions.addPage(200, 200);
     documentDimensions.addPage(100, 400);
     viewport.setDocumentDimensions(documentDimensions);
-    viewport.setZoom_(1);
+    viewport.setZoomForTest_(1);
     mockWindow.scrollTo(0, 0);
     viewport.fitToPage();
     chrome.test.assertEq(0.5, viewport.zoom);
     chrome.test.assertEq(0, viewport.position.x);
     chrome.test.assertEq(0, viewport.position.y);
-    viewport.setZoom_(1);
+    viewport.setZoomForTest_(1);
     mockWindow.scrollTo(0, 175);
     viewport.fitToPage();
     chrome.test.assertEq(0.25, viewport.zoom);
     // The page will be centred because it is less than the document width.
     chrome.test.assertEq(12.5, viewport.position.x);
     chrome.test.assertEq(50, viewport.position.y);
     chrome.test.succeed();
   },
 
   function testGoToPage() {
     var mockWindow = new MockWindow(100, 100);
     var mockSizer = new MockSizer();
     var mockCallback = new MockViewportChangedCallback();
-    var viewport = new Viewport(mockWindow, mockSizer,
-                                mockCallback.callback, 0);
+    var viewport = new Viewport(mockWindow, mockSizer, mockCallback.callback,
+                                function() {}, function() {}, 0);
     var documentDimensions = new MockDocumentDimensions();
 
     documentDimensions.addPage(100, 100);
     documentDimensions.addPage(200, 200);
     documentDimensions.addPage(100, 400);
     viewport.setDocumentDimensions(documentDimensions);
-    viewport.setZoom_(1);
+    viewport.setZoomForTest_(1);
 
     mockCallback.reset();
     viewport.goToPage(0);
     chrome.test.assertTrue(mockCallback.wasCalled);
     chrome.test.assertEq(0, viewport.position.x);
     chrome.test.assertEq(0, viewport.position.y);
 
     mockCallback.reset();
     viewport.goToPage(1);
     chrome.test.assertTrue(mockCallback.wasCalled);
     chrome.test.assertEq(0, viewport.position.x);
     chrome.test.assertEq(100, viewport.position.y);
 
     mockCallback.reset();
     viewport.goToPage(2);
     chrome.test.assertTrue(mockCallback.wasCalled);
     chrome.test.assertEq(0, viewport.position.x);
     chrome.test.assertEq(300, viewport.position.y);
 
-    viewport.setZoom_(0.5);
+    viewport.setZoomForTest_(0.5);
     mockCallback.reset();
     viewport.goToPage(2);
     chrome.test.assertTrue(mockCallback.wasCalled);
     chrome.test.assertEq(0, viewport.position.x);
     chrome.test.assertEq(150, viewport.position.y);
     chrome.test.succeed();
   },
 
   function testGetPageScreenRect() {
     var mockWindow = new MockWindow(100, 100);
     var mockSizer = new MockSizer();
     var mockCallback = new MockViewportChangedCallback();
-    var viewport = new Viewport(mockWindow, mockSizer,
-                                mockCallback.callback, 0);
+    var viewport = new Viewport(mockWindow, mockSizer, mockCallback.callback,
+                                function() {}, function() {}, 0);
     var documentDimensions = new MockDocumentDimensions();
     documentDimensions.addPage(100, 100);
     documentDimensions.addPage(200, 200);
     viewport.setDocumentDimensions(documentDimensions);
-    viewport.setZoom_(1);
+    viewport.setZoomForTest_(1);
 
     // Test that the rect of the first page is positioned/sized correctly.
     mockWindow.scrollTo(0, 0);
     var rect1 = viewport.getPageScreenRect(0);
     chrome.test.assertEq(Viewport.PAGE_SHADOW.left + 100 / 2, rect1.x);
     chrome.test.assertEq(Viewport.PAGE_SHADOW.top, rect1.y);
     chrome.test.assertEq(100 - Viewport.PAGE_SHADOW.right -
         Viewport.PAGE_SHADOW.left, rect1.width);
     chrome.test.assertEq(100 - Viewport.PAGE_SHADOW.bottom -
         Viewport.PAGE_SHADOW.top, rect1.height);
@@ skipping 10 matching lines @@
     // Check the rect of the second page is positioned/sized correctly.
     mockWindow.scrollTo(0, 100);
     rect1 = viewport.getPageScreenRect(1);
     chrome.test.assertEq(Viewport.PAGE_SHADOW.left, rect1.x);
     chrome.test.assertEq(Viewport.PAGE_SHADOW.top, rect1.y);
     chrome.test.assertEq(200 - Viewport.PAGE_SHADOW.right -
         Viewport.PAGE_SHADOW.left, rect1.width);
     chrome.test.assertEq(200 - Viewport.PAGE_SHADOW.bottom -
         Viewport.PAGE_SHADOW.top, rect1.height);
     chrome.test.succeed();
+  },
+
+  function testBeforeZoomAfterZoom() {
+    var mockWindow = new MockWindow(100, 100);
+    var mockSizer = new MockSizer();
+    var viewport;
+    var afterZoomCalled = false;
+    var beforeZoomCalled = false;
+    var afterZoom = function() {
+        afterZoomCalled = true;
+        chrome.test.assertTrue(beforeZoomCalled);
+        chrome.test.assertEq(0.5, viewport.zoom);
+    };
+    var beforeZoom = function() {
+        beforeZoomCalled = true;
+        chrome.test.assertFalse(afterZoomCalled);
+        chrome.test.assertEq(1, viewport.zoom);
+    };
+    viewport = new Viewport(mockWindow, mockSizer, function() {},
+                            beforeZoom, afterZoom, 0);
+    viewport.setZoomForTest_(0.5);
+    chrome.test.succeed();
   }
 ];
 
 chrome.test.runTests(tests);