1 | /*
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2 | * file: Events.js
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3 | *
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4 | * @BEGINLICENSE
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5 | * Copyright 2010 Brook Novak (email : [email protected])
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6 | * This program is free software; you can redistribute it and/or modify
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7 | * it under the terms of the GNU General Public License as published by
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8 | * the Free Software Foundation; either version 2 of the License, or
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9 | * (at your option) any later version.
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10 | * This program is distributed in the hope that it will be useful,
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11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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13 | * GNU General Public License for more details.
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14 | * You should have received a copy of the GNU General Public License
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15 | * along with this program; if not, write to the Free Software
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16 | * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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17 | * @ENDLICENSE
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18 | */
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19 | bootstrap.provides("events.Events");
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20 |
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21 | /**
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22 | * Adds an event handler to a DOM Event Source.
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23 | *
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24 | * If you are planning to listen for keyboard strokes, you can use "keystroke." This uses keydown and/or keypress
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25 | * and provides an extra argument to your handler containing the normalized key identifier string.
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26 | *
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27 | * @param {Object} eventSource The Element or Window to add the event to.
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28 | *
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29 | * @param {String} eventName The name of the dom event. Must be lowercase and omit the "on" prefix. For example "load" or "keypress".
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30 | *
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31 | * @param {Function} handler A function to handle the event being registered. When called, the dom event will
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32 | * be passed as the first (and only) argument.
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33 | */
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34 | function _addHandler(sourceEle, eventName, handlerFunc) {
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35 |
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36 | debug.assert(sourceEle.nodeType != Node.TEXT_NODE && sourceEle.nodeType != Node.COMMENT_NODE);
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37 | debug.assert(eventName.indexOf('on') !== 0);
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38 |
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39 | // IE has trouble passing the window object around - it can be cloned for no reason
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40 | if (sourceEle.setInterval && sourceEle != window)
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41 | sourceEle = window;
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42 |
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43 | switch(eventName) {
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44 |
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45 | case "keystroke":
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46 | // Keystroke is a combo of keydown and key press - normalizes
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47 | // key identifiers and passes them as extra arg to handler
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48 | addEventHandler(sourceEle, "keydown", function(e) {
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49 | var keyIndent = de.events.Keyboard.getKeyIdentifier(e, true);
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50 | if (keyIndent)
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51 | return handlerFunc(e, keyIndent);
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52 | });
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53 | addEventHandler(sourceEle, "keypress", function(e) {
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54 | var keyIndent = de.events.Keyboard.getKeyIdentifier(e, false);
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55 | if (keyIndent)
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56 | return handlerFunc(e, keyIndent);
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57 | });
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58 | break;
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59 |
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60 | case "mousedown": // Keep mouse state updated
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61 | addEventHandler(sourceEle, eventName, function(e) {
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62 | return de.events.Mouse.sniffMouseDownEvent(e) ? handlerFunc(e) : true;
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63 | });
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64 | break;
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65 | case "mouseup": // Keep mouse state updated
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66 | addEventHandler(sourceEle, eventName, function(e) {
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67 | return de.events.Mouse.sniffMouseUpEvent(e) ? handlerFunc(e) : true;
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68 | });
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69 | break;
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70 | case "mousemove": // Keep mouse state updated
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71 | addEventHandler(sourceEle, eventName, function(e) {
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72 | return de.events.Mouse.sniffMouseMoveEvent(e) ? handlerFunc(e) : true;
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73 | });
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74 | break;
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75 |
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76 | default:
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77 | addEventHandler(sourceEle, eventName, handlerFunc);
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78 | }
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79 |
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80 | function addEventHandler(sourceEle, eventName, actualHandler) {
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81 |
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82 | // Keep track of wrapper handlers for removal
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83 |
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84 | // Create event wrapper map (Event type -> tuple[event-source, wrapper handler])
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85 | if (!handlerFunc.evWrappers)
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86 | handlerFunc.evWrappers = {};
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87 |
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88 | // Ensure the map contains an entry for this event type
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89 | if (!handlerFunc.evWrappers[eventName])
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90 | handlerFunc.evWrappers[eventName] = [];
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91 |
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92 | // Store this event tuple
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93 | handlerFunc.evWrappers[eventName].push([sourceEle, forwardEvent]);
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94 |
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95 | if (sourceEle.addEventListener)
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96 | sourceEle.addEventListener(eventName, forwardEvent, false); // DOM Compliant
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97 |
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98 | else if (sourceEle.attachEvent)
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99 | sourceEle.attachEvent("on" + eventName, forwardEvent); // IE
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100 |
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101 | // @DEBUG ON
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102 | else debug.assert(false, "Unsupported browser: does not support addEventListener or attachEvent");
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103 | // @DEBUG OFF
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104 |
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105 | /**
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106 | * Wraps an event handler so that the event handler gets a non null event
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107 | * and if the handler returns false the event is consumed.
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108 | * @param {Event} e provided by native event dispatcher
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109 | */
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110 | function forwardEvent(e){
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111 | de.events.current = e = e || window.event;
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112 | try {
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113 | if (actualHandler(e) === false)
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114 | return de.events.consume(e);
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115 | } finally {
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116 | de.events.current = 0;
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117 | }
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118 | }
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119 |
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120 | }
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121 |
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122 | }
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123 |
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124 | /**
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125 | * Removes an event handler from a DOM Event Source.
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126 | *
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127 | * @param {Object} eventSource The Element or Window to add the event to.
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128 | *
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129 | * @param {String} eventName The name of the dom event. Must be lowercase and omit the "on" prefix. For example "load" or "keypress".
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130 | *
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131 | * @param {Function} handler The handler function to remove form the given event source.
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132 | */
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133 | function _removeHandler(sourceEle, eventName, handlerFunc){
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134 | debug.assert(eventName.indexOf('on') !== 0);
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135 |
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136 | // Keystoke is comprized of keydown and key press
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137 | if (eventName == "keystroke") {
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138 | _removeHandler(sourceEle, 'keydown', handlerFunc);
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139 | _removeHandler(sourceEle, 'keypress', handlerFunc);
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140 | return;
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141 | }
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142 |
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143 | // Check if the handler has been wrapped for this event type / source
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144 | if (handlerFunc.evWrappers && handlerFunc.evWrappers[eventName]) {
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145 |
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146 | // Look for wrapper handlers for this event type for this handler
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147 | for (var i in handlerFunc.evWrappers[eventName]) {
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148 |
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149 | var tuple = handlerFunc.evWrappers[eventName][i];
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150 |
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151 | // Was there a wrapped handler create for this handler on this event type and source?
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152 | if (tuple[0] == sourceEle) {
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153 |
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154 | // Remove tuple
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155 | if (handlerFunc.evWrappers[eventName].length == 1)
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156 | delete handlerFunc.evWrappers[eventName];
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157 | else
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158 | handlerFunc.evWrappers[eventName].splice(i, 1);
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159 |
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160 | // Assign handlerFunc to be the wrapped handler
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161 | handlerFunc = tuple[1];
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162 |
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163 | break;
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164 | }
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165 |
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166 | }
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167 |
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168 | }
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169 |
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170 | // Remove the handler from the event source
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171 | if (sourceEle.removeEventListener)
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172 | sourceEle.removeEventListener(eventName, handlerFunc, false); // DOM Compliant
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173 |
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174 | else if (sourceEle.detachEvent)
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175 | sourceEle.detachEvent("on" + eventName, handlerFunc); // IE
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176 |
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177 | // @DEBUG ON
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178 | else debug.assert(false, "Unsupported browser: does not support addEventListener or attachEvent");
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179 | // @DEBUG OFF
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180 |
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181 | }
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182 |
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183 |
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184 | $extend(de.events, {
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185 |
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186 | /**
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187 | * A pointer to the current event
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188 | */
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189 | current : 0,
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190 |
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191 | addHandler : _addHandler,
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192 |
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193 | removeHandler : _removeHandler,
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194 |
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195 | /**
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196 | * @param {Event} e An event
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197 | *
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198 | * @return {Object} The x and y coordinates of the event relative to the window.
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199 | */
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200 | getXYInWindowFromEvent : function(e){
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201 |
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202 | var targetX = 0, targetY = 0;
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203 |
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204 | if (e.clientX || e.clientX === 0) {
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205 | targetX = e.clientX;
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206 | targetY = e.clientY;
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207 | } else if (e.pageX != null) {
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208 | var scrollPos = _getDocumentScrollPos();
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209 | targetX = e.pageX - scrollPos.left;
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210 | targetY = e.pageY - scrollPos.top;
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211 | }
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212 |
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213 | return {x : targetX, y : targetY };
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214 | },
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215 |
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216 | /**
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217 | *
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218 | * @param {Event} e A dom event
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219 | * @return {Node} An element or text node which the event was targetted at.
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220 | */
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221 | getEventTarget: function(e) {
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222 | return e.target || e.srcElement || document;
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223 | },
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224 |
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225 | /**
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226 | * Consumes an event... stop is from propagating and prevents the default action.
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227 | *
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228 | * @example
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229 | * myhandlers = function(e) {
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230 | * ...
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231 | * if (somecondition) return de.events.consume(e);
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232 | * return true;
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233 | * }
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234 | *
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235 | * @param {Event} e A dom event.
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236 | *
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237 | * @return {Boolean} False always.
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238 | */
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239 | consume : function(e) {
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240 | de.events.stopPropogation(e);
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241 | de.events.preventDefault(e);
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242 | return false;
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243 | },
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244 |
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245 | /**
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246 | * Stops the event from propogating / bubbling.
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247 | * @param {Event} e A dom event.
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248 | */
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249 | stopPropogation : function(e) {
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250 | if (_engine == _Platform.TRIDENT)
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251 | e.cancelBubble = true;
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252 | else if (e.stopPropagation)
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253 | e.stopPropagation();
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254 | },
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255 |
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256 | /**
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257 | * Prevents the default behaviour from occuring on a given event.
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258 | * @param {Event} e An event object
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259 | */
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260 | preventDefault : function(e) {
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261 | if (_engine == _Platform.TRIDENT)
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262 | e.returnValue = false;
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263 | else if(e.preventDefault)
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264 | e.preventDefault();
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265 | }
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266 |
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267 | });
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268 |
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