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1 // Copyright 2015 The Chromium Authors. All rights reserved. | |
Sam McNally
2015/02/11 06:59:13
Let's call this viewport_scroller.js.
Deepak
2015/02/11 10:29:56
Done.
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2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 'use strict'; | |
6 | |
7 | |
Sam McNally
2015/02/11 06:59:13
Remove.
Deepak
2015/02/11 10:29:55
Done.
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8 /** | |
9 * The period of time to wait between updating the viewport position by the | |
10 * scroll velocity. | |
11 */ | |
12 ViewportScroller.DRAG_TIMER_INTERVAL = 100; | |
Sam McNally
2015/02/11 06:59:13
I think we can make these private.
Deepak
2015/02/11 10:29:55
Done.
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13 | |
14 /** | |
15 * The maximum drag scroll velocity when we have selection and drag mouse out | |
Sam McNally
2015/02/11 06:59:13
The maximum drag scroll velocity.
Deepak
2015/02/11 10:29:56
Done.
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16 * of viewport. | |
17 */ | |
18 ViewportScroller.MAX_SCROLL_VELOCITY = 100; | |
19 | |
20 /** | |
21 * Creates a new ViewportScroller for scrolling viewport when have selection | |
Sam McNally
2015/02/11 06:59:13
Creates a new ViewportScroller.
A ViewportScrolle
Deepak
2015/02/11 10:29:56
Done.
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22 * and mouse is dragging out of the viewport. | |
23 * @param {Object} viewport The viewport info of the page. | |
24 * @param {Object} plugin The plugin object of PDF. | |
25 * @param {Object} window The window object for PDF. | |
26 */ | |
27 function ViewportScroller(viewport, plugin, window) { | |
28 this.viewport_ = viewport; | |
29 this.plugin_ = plugin; | |
30 this.window_ = window; | |
31 this.mousemoveCallback_ = null; | |
32 this.timerId_ = null; | |
33 this.scrollVelocity_ = null; | |
34 } | |
35 | |
36 ViewportScroller.prototype = { | |
37 | |
38 /** | |
39 * @private | |
40 * Start the timer to call dragScrollPage_ function at regular interval until | |
Sam McNally
2015/02/11 06:59:12
Start scrolling the page by |scrollVelocity_| ever
Deepak
2015/02/11 10:29:55
Done.
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41 * the timer is stopped. | |
42 */ | |
43 startDragScrollTimer_: function() { | |
44 this.timerId_ = this.window_.setInterval( | |
Sam McNally
2015/02/11 06:59:13
if (this.timerId === null)
Deepak
2015/02/11 10:29:56
Done.
Deepak
2015/02/11 10:29:56
Done.
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45 this.dragScrollPage_.bind(this), ViewportScroller.DRAG_TIMER_INTERVAL); | |
46 }, | |
47 | |
48 /** | |
49 * @private | |
50 * Stops the drag scroll timer if it is active. | |
51 */ | |
52 stopDragScrollTimer_: function() { | |
53 if (this.timerId_ !== null) { | |
54 this.window_.clearInterval(this.timerId_); | |
55 this.timerId_ = null; | |
56 } | |
57 }, | |
58 | |
59 /** | |
60 * @private | |
61 * Scrolls the viewport by the current scroll velocity. | |
62 */ | |
63 dragScrollPage_: function() { | |
64 var position = this.viewport_.position; | |
65 position.y += this.scrollVelocity_.y; | |
66 position.x += this.scrollVelocity_.x; | |
67 this.viewport_.position = position; | |
68 }, | |
69 | |
70 /** | |
71 * @private | |
72 * Calculate the velocity to scroll while dragging using the distance of the | |
73 * cursor outside the viewport. | |
74 * @return {Object} Object with x and y direction scroll velocity. | |
75 */ | |
76 calculateVelocity_: function(event) { | |
77 var x = Math.min(Math.max(-event.offsetX, | |
78 event.offsetX - this.plugin_.offsetWidth, 0), | |
79 ViewportScroller.MAX_SCROLL_VELOCITY) * | |
80 Math.sign(event.offsetX); | |
81 var y = Math.min(Math.max(-event.offsetY, | |
82 event.offsetY - this.plugin_.offsetHeight, 0), | |
83 ViewportScroller.MAX_SCROLL_VELOCITY) * | |
84 Math.sign(event.offsetY); | |
85 return { | |
86 x: x, | |
87 y: y | |
88 }; | |
89 }, | |
90 | |
91 /** | |
92 * @private | |
93 * Handles mousemove events. It updates the scroll velocity and starts and | |
94 * stops timer based on scroll velocity. | |
95 * @param {Object} event The mousemove event. | |
96 */ | |
97 selectionDragListener_: function(event) { | |
Sam McNally
2015/02/11 06:59:13
onMousemove_
Deepak
2015/02/11 10:29:55
Done.
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98 this.scrollVelocity_ = this.calculateVelocity_(event); | |
99 if (!this.scrollVelocity_.x && !this.scrollVelocity_.y) | |
100 this.stopDragScrollTimer_(); | |
101 else if (!this.timerId_) | |
102 this.startDragScrollTimer_(); | |
103 }, | |
104 | |
105 /** | |
106 * @private | |
Sam McNally
2015/02/11 06:59:13
Remove.
Deepak
2015/02/11 10:29:55
Done.
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107 * Function to add and remove callback function when mousemove event comes. | |
Sam McNally
2015/02/11 06:59:12
Sets whether to scroll the viewport when the mouse
Deepak
2015/02/11 10:29:55
Done.
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108 * @param {boolean} isSelecting Represents selection status. | |
109 */ | |
110 viewportScroll: function(isSelecting) { | |
Sam McNally
2015/02/11 06:59:13
How about calling this setEnableScrolling?
Deepak
2015/02/11 10:29:56
Done.
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111 if (isSelecting) { | |
112 if (!this.mousemoveCallback_) | |
113 this.mousemoveCallback_ = this.selectionDragListener_.bind(this); | |
114 this.plugin_.addEventListener('mousemove', this.mousemoveCallback_, | |
115 false); | |
116 } else { | |
117 this.stopDragScrollTimer_(); | |
118 if (this.mousemoveCallback_) { | |
119 this.plugin_.removeEventListener('mousemove', this.mousemoveCallback_, | |
120 false); | |
121 } | |
122 } | |
123 } | |
124 }; | |
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