src/third_party/trace-viewer/third_party/tvcm/src/tvcm/ui/mouse_tracker.js

   1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
   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 /**
   8  * @fileoverview A Mouse-event abtraction that waits for
   9  *   mousedown, then watches for subsequent mousemove events
  10  *   until the next mouseup event, then waits again.
  11  *   State changes are signaled with
  12  *      'mouse-tracker-start' : mousedown and tracking
  13  *      'mouse-tracker-move' : mouse move
  14  *      'mouse-tracker-end' : mouseup and not tracking.
  15  */
  16
  17 tvcm.exportTo('tvcm.ui', function() {
  18
  19   /**
  20    * @constructor
  21    * @param {HTMLElement} targetElement will recv events 'mouse-tracker-start',
  22    *     'mouse-tracker-move', 'mouse-tracker-end'.
  23    */
  24   function MouseTracker(opt_targetElement) {
  25     this.onMouseDown_ = this.onMouseDown_.bind(this);
  26     this.onMouseMove_ = this.onMouseMove_.bind(this);
  27     this.onMouseUp_ = this.onMouseUp_.bind(this);
  28
  29     this.targetElement = opt_targetElement;
  30   }
  31
  32   MouseTracker.prototype = {
  33
  34     get targetElement() {
  35       return this.targetElement_;
  36     },
  37
  38     set targetElement(targetElement) {
  39       if (this.targetElement_)
  40         this.targetElement_.removeEventListener('mousedown', this.onMouseDown_);
  41       this.targetElement_ = targetElement;
  42       if (this.targetElement_)
  43         this.targetElement_.addEventListener('mousedown', this.onMouseDown_);
  44     },
  45
  46     onMouseDown_: function(e) {
  47       if (e.button !== 0)
  48         return true;
  49
  50       e = this.remakeEvent_(e, 'mouse-tracker-start');
  51       this.targetElement_.dispatchEvent(e);
  52       document.addEventListener('mousemove', this.onMouseMove_);
  53       document.addEventListener('mouseup', this.onMouseUp_);
  54       this.targetElement_.addEventListener('blur', this.onMouseUp_);
  55       this.savePreviousUserSelect_ = document.body.style['-webkit-user-select'];
  56       document.body.style['-webkit-user-select'] = 'none';
  57       e.preventDefault();
  58       return true;
  59     },
  60
  61     onMouseMove_: function(e) {
  62       e = this.remakeEvent_(e, 'mouse-tracker-move');
  63       this.targetElement_.dispatchEvent(e);
  64     },
  65
  66     onMouseUp_: function(e) {
  67       document.removeEventListener('mousemove', this.onMouseMove_);
  68       document.removeEventListener('mouseup', this.onMouseUp_);
  69       this.targetElement_.removeEventListener('blur', this.onMouseUp_);
  70       document.body.style['-webkit-user-select'] =
  71           this.savePreviousUserSelect_;
  72       e = this.remakeEvent_(e, 'mouse-tracker-end');
  73       this.targetElement_.dispatchEvent(e);
  74     },
  75
  76     remakeEvent_: function(e, newType) {
  77       var remade = new tvcm.Event(newType, true, true);
  78       remade.x = e.x;
  79       remade.y = e.y;
  80       remade.offsetX = e.offsetX;
  81       remade.offsetY = e.offsetY;
  82       remade.clientX = e.clientX;
  83       remade.clientY = e.clientY;
  84       return remade;
  85     }
  86
  87   };
  88
  89   function trackMouseMovesUntilMouseUp(mouseMoveHandler, opt_mouseUpHandler) {
  90     function cleanupAndDispatchToMouseUp(e) {
  91       document.removeEventListener('mousemove', mouseMoveHandler);
  92       document.removeEventListener('mouseup', cleanupAndDispatchToMouseUp);
  93       if (opt_mouseUpHandler)
  94         opt_mouseUpHandler(e);
  95     }
  96     document.addEventListener('mousemove', mouseMoveHandler);
  97     document.addEventListener('mouseup', cleanupAndDispatchToMouseUp);
  98   }
  99
 100   return {
 101     MouseTracker: MouseTracker,
 102     trackMouseMovesUntilMouseUp: trackMouseMovesUntilMouseUp
 103   };
 104 });