Improved Pinch-Zoom for PDF.

chrome/test/data/pdf/gesture_detector_test.js

+// Copyright 2016 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.
+
+chrome.test.runTests(function() {
+  'use strict';
+
+  class StubElement {
+    constructor() {
+      this.listeners_ = new Map([
+        ['touchstart', []],
+        ['touchmove', []],
+        ['touchend', []],
+        ['touchcancel', []]
+      ]);
+    }
+
+    addEventListener(type, listener) {
+      if (this.listeners_.has(type))
+        this.listeners_.get(type).push(listener);
+    }
+
+    sendEvent(event) {
+      for (let l of this.listeners_.get(event.type))
+        l(event);
+    }
+  }
+
+  class MockTouchEvent {
+    constructor(type, touches) {
+      this.type = type;
+      this.touches = touches;
+      this.defaultPrevented = false;
+    }
+
+    preventDefault() {
+      this.defaultPrevented = true;
+    }
+  }
+
+  class PinchListener {
+    constructor(gestureDetector) {
+      this.lastEvent = null;
+      gestureDetector.addEventListener('pinchstart', this.onPinch_.bind(this));
+      gestureDetector.addEventListener('pinchupdate', this.onPinch_.bind(this));
+      gestureDetector.addEventListener('pinchend', this.onPinch_.bind(this));
+    }
+
+    onPinch_(pinchEvent) {
+      this.lastEvent = pinchEvent;
+    }
+  }
+
+  return [
+    function testPinchZoomIn() {
+      let stubElement = new StubElement();
+      let gestureDetector = new GestureDetector(stubElement);
+      let pinchListener = new PinchListener(gestureDetector);
+
+      stubElement.sendEvent(new MockTouchEvent('touchstart', [
+        {clientX: 0, clientY: 0},
+        {clientX: 0, clientY: 2}
+      ]));
+      chrome.test.assertEq({
+        type: 'pinchstart',
+        center: {x: 0, y: 1}
+      }, pinchListener.lastEvent);
+
+      stubElement.sendEvent(new MockTouchEvent('touchmove', [
+        {clientX: 0, clientY: 0},
+        {clientX: 0, clientY: 4}
+      ]));
+      chrome.test.assertEq({
+        type: 'pinchupdate',
+        scaleRatio: 2,
+        direction: 'in',
+        startScaleRatio: 2,
+        center: {x: 0, y: 2}
+      }, pinchListener.lastEvent);
+
+      stubElement.sendEvent(new MockTouchEvent('touchmove', [
+        {clientX: 0, clientY: 0},
+        {clientX: 0, clientY: 8}
+      ]));
+      chrome.test.assertEq({
+        type: 'pinchupdate',
+        scaleRatio: 2,
+        direction: 'in',
+        startScaleRatio: 4,
+        center: {x: 0, y: 4}
+      }, pinchListener.lastEvent);
+
+      stubElement.sendEvent(new MockTouchEvent('touchend', []));
+      chrome.test.assertEq({
+        type: 'pinchend',
+        startScaleRatio: 4,
+        center: {x: 0, y: 4}
+      }, pinchListener.lastEvent);
+
+      chrome.test.succeed();
+    },
+
+    function testPinchZoomInAndBackOut() {
+      let stubElement = new StubElement();
+      let gestureDetector = new GestureDetector(stubElement);
+      let pinchListener = new PinchListener(gestureDetector);
+
+      stubElement.sendEvent(new MockTouchEvent('touchstart', [
+        {clientX: 0, clientY: 0},
+        {clientX: 0, clientY: 2}
+      ]));
+      chrome.test.assertEq({
+        type: 'pinchstart',
+        center: {x: 0, y: 1}
+      }, pinchListener.lastEvent);
+
+      stubElement.sendEvent(new MockTouchEvent('touchmove', [
+        {clientX: 0, clientY: 0},
+        {clientX: 0, clientY: 4}
+      ]));
+      chrome.test.assertEq({
+        type: 'pinchupdate',
+        scaleRatio: 2,
+        direction: 'in',
+        startScaleRatio: 2,
+        center: {x: 0, y: 2}
+      }, pinchListener.lastEvent);
+
+      stubElement.sendEvent(new MockTouchEvent('touchmove', [
+        {clientX: 0, clientY: 0},
+        {clientX: 0, clientY: 2}
+      ]));
+      // This should be part of the same gesture as an update.
+      // A change in direction should not end the gesture and start a new one.
+      chrome.test.assertEq({
+        type: 'pinchupdate',
+        scaleRatio: 0.5,
+        direction: 'out',
+        startScaleRatio: 1,
+        center: {x: 0, y: 1}
+      }, pinchListener.lastEvent);
+
+      stubElement.sendEvent(new MockTouchEvent('touchend', []));
+      chrome.test.assertEq({
+        type: 'pinchend',
+        startScaleRatio: 1,
+        center: {x: 0, y: 1}
+      }, pinchListener.lastEvent);
+
+      chrome.test.succeed();
+    },
+
+    function testIgnoreTouchScrolling() {
+      let stubElement = new StubElement();
+      let gestureDetector = new GestureDetector(stubElement);
+      let pinchListener = new PinchListener(gestureDetector);
+
+      let touchScrollStartEvent = new MockTouchEvent('touchstart', [
+        {clientX: 0, clientY: 0},
+      ]);
+      stubElement.sendEvent(touchScrollStartEvent);
+      chrome.test.assertEq(null, pinchListener.lastEvent);
+      chrome.test.assertFalse(touchScrollStartEvent.defaultPrevented);
+
+      stubElement.sendEvent(new MockTouchEvent('touchmove', [
+        {clientX: 0, clientY: 1},
+      ]));
+      chrome.test.assertEq(null, pinchListener.lastEvent);
+
+      stubElement.sendEvent(new MockTouchEvent('touchend', []));
+      chrome.test.assertEq(null, pinchListener.lastEvent);
+
+      chrome.test.succeed();
+    },
+
+    function testPreventNativePinchZoom() {
+      let stubElement = new StubElement();
+      let gestureDetector = new GestureDetector(stubElement);
+      let pinchListener = new PinchListener(gestureDetector);
+
+      let pinchStartEvent = new MockTouchEvent('touchstart', [
+        {clientX: 0, clientY: 0},
+        {clientX: 0, clientY: 2}
+      ]);
+      stubElement.sendEvent(pinchStartEvent);
+      chrome.test.assertEq('pinchstart', pinchListener.lastEvent.type);
+      chrome.test.assertTrue(pinchStartEvent.defaultPrevented);
+
+      chrome.test.succeed();
+    }
+  ];
+}());