[76] | 1 | /* Copyright (c) 2006-2010 by OpenLayers Contributors (see authors.txt for |
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| 2 | * full list of contributors). Published under the Clear BSD license. |
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| 3 | * See http://svn.openlayers.org/trunk/openlayers/license.txt for the |
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| 4 | * full text of the license. */ |
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| 5 | |
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| 6 | /** |
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| 7 | * @requires OpenLayers/Control.js |
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| 8 | * @requires OpenLayers/Layer/Vector.js |
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| 9 | */ |
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| 10 | |
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| 11 | /** |
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| 12 | * Class: OpenLayers.Control.Snapping |
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| 13 | * Acts as a snapping agent while editing vector features. |
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| 14 | * |
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| 15 | * Inherits from: |
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| 16 | * - <OpenLayers.Control> |
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| 17 | */ |
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| 18 | OpenLayers.Control.Snapping = OpenLayers.Class(OpenLayers.Control, { |
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| 19 | |
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| 20 | /** |
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| 21 | * Constant: EVENT_TYPES |
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| 22 | * {Array(String)} Supported application event types. Register a listener |
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| 23 | * for a particular event with the following syntax: |
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| 24 | * (code) |
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| 25 | * control.events.register(type, obj, listener); |
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| 26 | * (end) |
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| 27 | * |
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| 28 | * Listeners will be called with a reference to an event object. The |
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| 29 | * properties of this event depends on exactly what happened. |
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| 30 | * |
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| 31 | * Supported control event types (in addition to those from <OpenLayers.Control>): |
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| 32 | * beforesnap - Triggered before a snap occurs. Listeners receive an |
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| 33 | * event object with *point*, *x*, *y*, *distance*, *layer*, and |
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| 34 | * *snapType* properties. The point property will be original point |
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| 35 | * geometry considered for snapping. The x and y properties represent |
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| 36 | * coordinates the point will receive. The distance is the distance |
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| 37 | * of the snap. The layer is the target layer. The snapType property |
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| 38 | * will be one of "node", "vertex", or "edge". Return false to stop |
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| 39 | * snapping from occurring. |
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| 40 | * snap - Triggered when a snap occurs. Listeners receive an event with |
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| 41 | * *point*, *snapType*, *layer*, and *distance* properties. The point |
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| 42 | * will be the location snapped to. The snapType will be one of "node", |
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| 43 | * "vertex", or "edge". The layer will be the target layer. The |
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| 44 | * distance will be the distance of the snap in map units. |
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| 45 | * unsnap - Triggered when a vertex is unsnapped. Listeners receive an |
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| 46 | * event with a *point* property. |
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| 47 | */ |
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| 48 | EVENT_TYPES: ["beforesnap", "snap", "unsnap"], |
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| 49 | |
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| 50 | /** |
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| 51 | * CONSTANT: DEFAULTS |
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| 52 | * Default target properties. |
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| 53 | */ |
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| 54 | DEFAULTS: { |
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| 55 | tolerance: 10, |
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| 56 | node: true, |
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| 57 | edge: true, |
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| 58 | vertex: true |
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| 59 | }, |
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| 60 | |
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| 61 | /** |
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| 62 | * Property: greedy |
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| 63 | * {Boolean} Snap to closest feature in first layer with an eligible |
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| 64 | * feature. Default is true. |
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| 65 | */ |
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| 66 | greedy: true, |
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| 67 | |
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| 68 | /** |
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| 69 | * Property: precedence |
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| 70 | * {Array} List representing precedence of different snapping types. |
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| 71 | * Default is "node", "vertex", "edge". |
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| 72 | */ |
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| 73 | precedence: ["node", "vertex", "edge"], |
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| 74 | |
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| 75 | /** |
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| 76 | * Property: resolution |
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| 77 | * {Float} The map resolution for the previously considered snap. |
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| 78 | */ |
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| 79 | resolution: null, |
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| 80 | |
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| 81 | /** |
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| 82 | * Property: geoToleranceCache |
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| 83 | * {Object} A cache of geo-tolerances. Tolerance values (in map units) are |
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| 84 | * calculated when the map resolution changes. |
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| 85 | */ |
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| 86 | geoToleranceCache: null, |
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| 87 | |
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| 88 | /** |
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| 89 | * Property: layer |
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| 90 | * {<OpenLayers.Layer.Vector>} The current editable layer. Set at |
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| 91 | * construction or after construction with <setLayer>. |
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| 92 | */ |
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| 93 | layer: null, |
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| 94 | |
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| 95 | /** |
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| 96 | * Property: feature |
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| 97 | * {<OpenLayers.Feature.Vector>} The current editable feature. |
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| 98 | */ |
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| 99 | feature: null, |
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| 100 | |
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| 101 | /** |
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| 102 | * Property: point |
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| 103 | * {<OpenLayers.Geometry.Point>} The currently snapped vertex. |
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| 104 | */ |
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| 105 | point: null, |
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| 106 | |
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| 107 | /** |
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| 108 | * Constructor: OpenLayers.Control.Snapping |
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| 109 | * Creates a new snapping control. A control is constructed with an editable |
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| 110 | * layer and a set of configuration objects for target layers. While the |
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| 111 | * control is active, dragging vertices while drawing new features or |
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| 112 | * modifying existing features on the editable layer will engage |
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| 113 | * snapping to features on the target layers. Whether a vertex snaps to |
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| 114 | * a feature on a target layer depends on the target layer configuration. |
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| 115 | * |
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| 116 | * Parameters: |
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| 117 | * options - {Object} An object containing all configuration properties for |
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| 118 | * the control. |
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| 119 | * |
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| 120 | * Valid options: |
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| 121 | * layer - {OpenLayers.Layer.Vector} The editable layer. Features from this |
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| 122 | * layer that are digitized or modified may have vertices snapped to |
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| 123 | * features from any of the target layers. |
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| 124 | * targets - {Array(Object | OpenLayers.Layer.Vector)} A list of objects for |
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| 125 | * configuring target layers. See valid properties of the target |
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| 126 | * objects below. If the items in the targets list are vector layers |
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| 127 | * (instead of configuration objects), the defaults from the <defaults> |
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| 128 | * property will apply. The editable layer itself may be a target |
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| 129 | * layer - allowing newly created or edited features to be snapped to |
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| 130 | * existing features from the same layer. If no targets are provided |
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| 131 | * the layer given in the constructor (as <layer>) will become the |
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| 132 | * initial target. |
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| 133 | * defaults - {Object} An object with default properties to be applied |
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| 134 | * to all target objects. |
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| 135 | * greedy - {Boolean} Snap to closest feature in first target layer that |
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| 136 | * applies. Default is true. If false, all features in all target |
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| 137 | * layers will be checked and the closest feature in all target layers |
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| 138 | * will be chosen. The greedy property determines if the order of the |
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| 139 | * target layers is significant. By default, the order of the target |
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| 140 | * layers is significant where layers earlier in the target layer list |
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| 141 | * have precedence over layers later in the list. Within a single |
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| 142 | * layer, the closest feature is always chosen for snapping. This |
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| 143 | * property only determines whether the search for a closer feature |
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| 144 | * continues after an eligible feature is found in a target layer. |
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| 145 | * |
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| 146 | * Valid target properties: |
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| 147 | * layer - {OpenLayers.Layer.Vector} A target layer. Features from this |
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| 148 | * layer will be eligible to act as snapping target for the editable |
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| 149 | * layer. |
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| 150 | * tolerance - {Float} The distance (in pixels) at which snapping may occur. |
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| 151 | * Default is 10. |
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| 152 | * node - {Boolean} Snap to nodes (first or last point in a geometry) in |
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| 153 | * target layer. Default is true. |
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| 154 | * nodeTolerance - {Float} Optional distance at which snapping may occur |
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| 155 | * for nodes specifically. If none is provided, <tolerance> will be |
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| 156 | * used. |
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| 157 | * vertex - {Boolean} Snap to vertices in target layer. Default is true. |
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| 158 | * vertexTolerance - {Float} Optional distance at which snapping may occur |
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| 159 | * for vertices specifically. If none is provided, <tolerance> will be |
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| 160 | * used. |
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| 161 | * edge - {Boolean} Snap to edges in target layer. Default is true. |
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| 162 | * edgeTolerance - {Float} Optional distance at which snapping may occur |
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| 163 | * for edges specifically. If none is provided, <tolerance> will be |
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| 164 | * used. |
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| 165 | * filter - {OpenLayers.Filter} Optional filter to evaluate to determine if |
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| 166 | * feature is eligible for snapping. If filter evaluates to true for a |
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| 167 | * target feature a vertex may be snapped to the feature. |
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| 168 | */ |
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| 169 | initialize: function(options) { |
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| 170 | // concatenate events specific to measure with those from the base |
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| 171 | Array.prototype.push.apply( |
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| 172 | this.EVENT_TYPES, OpenLayers.Control.prototype.EVENT_TYPES |
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| 173 | ); |
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| 174 | OpenLayers.Control.prototype.initialize.apply(this, [options]); |
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| 175 | this.options = options || {}; // TODO: this could be done by the super |
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| 176 | |
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| 177 | // set the editable layer if provided |
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| 178 | if(this.options.layer) { |
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| 179 | this.setLayer(this.options.layer); |
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| 180 | } |
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| 181 | // configure target layers |
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| 182 | var defaults = OpenLayers.Util.extend({}, this.options.defaults); |
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| 183 | this.defaults = OpenLayers.Util.applyDefaults(defaults, this.DEFAULTS); |
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| 184 | this.setTargets(this.options.targets); |
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| 185 | if(this.targets.length === 0 && this.layer) { |
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| 186 | this.addTargetLayer(this.layer); |
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| 187 | } |
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| 188 | |
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| 189 | this.geoToleranceCache = {}; |
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| 190 | }, |
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| 191 | |
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| 192 | /** |
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| 193 | * APIMethod: setLayer |
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| 194 | * Set the editable layer. Call the setLayer method if the editable layer |
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| 195 | * changes and the same control should be used on a new editable layer. |
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| 196 | * If the control is already active, it will be active after the new |
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| 197 | * layer is set. |
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| 198 | * |
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| 199 | * Parameters: |
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| 200 | * layer - {OpenLayers.Layer.Vector} The new editable layer. |
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| 201 | */ |
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| 202 | setLayer: function(layer) { |
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| 203 | if(this.active) { |
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| 204 | this.deactivate(); |
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| 205 | this.layer = layer; |
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| 206 | this.activate(); |
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| 207 | } else { |
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| 208 | this.layer = layer; |
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| 209 | } |
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| 210 | }, |
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| 211 | |
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| 212 | /** |
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| 213 | * Method: setTargets |
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| 214 | * Set the targets for the snapping agent. |
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| 215 | * |
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| 216 | * Parameters: |
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| 217 | * targets - {Array} An array of target configs or target layers. |
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| 218 | */ |
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| 219 | setTargets: function(targets) { |
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| 220 | this.targets = []; |
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| 221 | if(targets && targets.length) { |
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| 222 | var target; |
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| 223 | for(var i=0, len=targets.length; i<len; ++i) { |
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| 224 | target = targets[i]; |
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| 225 | if(target instanceof OpenLayers.Layer.Vector) { |
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| 226 | this.addTargetLayer(target); |
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| 227 | } else { |
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| 228 | this.addTarget(target); |
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| 229 | } |
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| 230 | } |
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| 231 | } |
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| 232 | }, |
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| 233 | |
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| 234 | /** |
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| 235 | * Method: addTargetLayer |
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| 236 | * Add a target layer with the default target config. |
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| 237 | * |
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| 238 | * Parameters: |
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| 239 | * layer - {<OpenLayers.Layer.Vector>} A target layer. |
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| 240 | */ |
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| 241 | addTargetLayer: function(layer) { |
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| 242 | this.addTarget({layer: layer}); |
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| 243 | }, |
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| 244 | |
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| 245 | /** |
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| 246 | * Method: addTarget |
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| 247 | * Add a configured target layer. |
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| 248 | * |
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| 249 | * Parameters: |
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| 250 | * target - {Object} A target config. |
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| 251 | */ |
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| 252 | addTarget: function(target) { |
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| 253 | target = OpenLayers.Util.applyDefaults(target, this.defaults); |
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| 254 | target.nodeTolerance = target.nodeTolerance || target.tolerance; |
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| 255 | target.vertexTolerance = target.vertexTolerance || target.tolerance; |
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| 256 | target.edgeTolerance = target.edgeTolerance || target.tolerance; |
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| 257 | this.targets.push(target); |
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| 258 | }, |
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| 259 | |
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| 260 | /** |
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| 261 | * Method: removeTargetLayer |
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| 262 | * Remove a target layer. |
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| 263 | * |
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| 264 | * Parameters: |
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| 265 | * layer - {<OpenLayers.Layer.Vector>} The target layer to remove. |
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| 266 | */ |
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| 267 | removeTargetLayer: function(layer) { |
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| 268 | var target; |
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| 269 | for(var i=this.targets.length-1; i>=0; --i) { |
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| 270 | target = this.targets[i]; |
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| 271 | if(target.layer === layer) { |
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| 272 | this.removeTarget(target); |
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| 273 | } |
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| 274 | } |
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| 275 | }, |
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| 276 | |
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| 277 | /** |
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| 278 | * Method: removeTarget |
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| 279 | * Remove a target. |
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| 280 | * |
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| 281 | * Parameters: |
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| 282 | * target - {Object} A target config. |
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| 283 | * |
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| 284 | * Returns: |
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| 285 | * {Array} The targets array. |
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| 286 | */ |
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| 287 | removeTarget: function(target) { |
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| 288 | return OpenLayers.Util.removeItem(this.targets, target); |
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| 289 | }, |
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| 290 | |
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| 291 | /** |
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| 292 | * APIMethod: activate |
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| 293 | * Activate the control. Activating the control registers listeners for |
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| 294 | * editing related events so that during feature creation and |
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| 295 | * modification, moving vertices will trigger snapping. |
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| 296 | */ |
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| 297 | activate: function() { |
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| 298 | var activated = OpenLayers.Control.prototype.activate.call(this); |
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| 299 | if(activated) { |
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| 300 | if(this.layer && this.layer.events) { |
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| 301 | this.layer.events.on({ |
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| 302 | sketchstarted: this.onSketchModified, |
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| 303 | sketchmodified: this.onSketchModified, |
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| 304 | vertexmodified: this.onVertexModified, |
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| 305 | scope: this |
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| 306 | }); |
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| 307 | } |
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| 308 | } |
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| 309 | return activated; |
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| 310 | }, |
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| 311 | |
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| 312 | /** |
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| 313 | * APIMethod: deactivate |
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| 314 | * Deactivate the control. Deactivating the control unregisters listeners |
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| 315 | * so feature editing may proceed without engaging the snapping agent. |
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| 316 | */ |
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| 317 | deactivate: function() { |
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| 318 | var deactivated = OpenLayers.Control.prototype.deactivate.call(this); |
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| 319 | if(deactivated) { |
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| 320 | if(this.layer && this.layer.events) { |
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| 321 | this.layer.events.un({ |
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| 322 | sketchstarted: this.onSketchModified, |
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| 323 | sketchmodified: this.onSketchModified, |
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| 324 | vertexmodified: this.onVertexModified, |
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| 325 | scope: this |
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| 326 | }); |
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| 327 | } |
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| 328 | } |
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| 329 | this.feature = null; |
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| 330 | this.point = null; |
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| 331 | return deactivated; |
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| 332 | }, |
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| 333 | |
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| 334 | /** |
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| 335 | * Method: onSketchModified |
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| 336 | * Registered as a listener for the sketchmodified event on the editable |
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| 337 | * layer. |
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| 338 | * |
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| 339 | * Parameters: |
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| 340 | * event - {Object} The sketch modified event. |
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| 341 | */ |
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| 342 | onSketchModified: function(event) { |
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| 343 | this.feature = event.feature; |
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| 344 | this.considerSnapping(event.vertex, event.vertex); |
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| 345 | }, |
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| 346 | |
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| 347 | /** |
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| 348 | * Method: onVertexModified |
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| 349 | * Registered as a listener for the vertexmodified event on the editable |
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| 350 | * layer. |
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| 351 | * |
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| 352 | * Parameters: |
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| 353 | * event - {Object} The vertex modified event. |
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| 354 | */ |
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| 355 | onVertexModified: function(event) { |
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| 356 | this.feature = event.feature; |
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| 357 | var loc = this.layer.map.getLonLatFromViewPortPx(event.pixel); |
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| 358 | this.considerSnapping( |
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| 359 | event.vertex, new OpenLayers.Geometry.Point(loc.lon, loc.lat) |
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| 360 | ); |
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| 361 | }, |
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| 362 | |
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| 363 | /** |
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| 364 | * Method: considerSnapping |
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| 365 | * |
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| 366 | * Parameters: |
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| 367 | * point - {<OpenLayers.Geometry.Point}} The vertex to be snapped (or |
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| 368 | * unsnapped). |
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| 369 | * loc - {<OpenLayers.Geometry.Point>} The location of the mouse in map |
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| 370 | * coords. |
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| 371 | */ |
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| 372 | considerSnapping: function(point, loc) { |
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| 373 | var best = { |
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| 374 | rank: Number.POSITIVE_INFINITY, |
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| 375 | dist: Number.POSITIVE_INFINITY, |
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| 376 | x: null, y: null |
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| 377 | }; |
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| 378 | var snapped = false; |
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| 379 | var result, target; |
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| 380 | for(var i=0, len=this.targets.length; i<len; ++i) { |
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| 381 | target = this.targets[i]; |
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| 382 | result = this.testTarget(target, loc); |
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| 383 | if(result) { |
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| 384 | if(this.greedy) { |
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| 385 | best = result; |
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| 386 | best.target = target; |
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| 387 | snapped = true; |
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| 388 | break; |
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| 389 | } else { |
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| 390 | if((result.rank < best.rank) || |
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| 391 | (result.rank === best.rank && result.dist < best.dist)) { |
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| 392 | best = result; |
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| 393 | best.target = target; |
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| 394 | snapped = true; |
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| 395 | } |
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| 396 | } |
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| 397 | } |
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| 398 | } |
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| 399 | if(snapped) { |
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| 400 | var proceed = this.events.triggerEvent("beforesnap", { |
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| 401 | point: point, x: best.x, y: best.y, distance: best.dist, |
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| 402 | layer: best.target.layer, snapType: this.precedence[best.rank] |
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| 403 | }); |
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| 404 | if(proceed !== false) { |
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| 405 | point.x = best.x; |
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| 406 | point.y = best.y; |
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| 407 | this.point = point; |
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| 408 | this.events.triggerEvent("snap", { |
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| 409 | point: point, |
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| 410 | snapType: this.precedence[best.rank], |
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| 411 | layer: best.target.layer, |
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| 412 | distance: best.dist |
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| 413 | }); |
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| 414 | } else { |
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| 415 | snapped = false; |
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| 416 | } |
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| 417 | } |
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| 418 | if(this.point && !snapped) { |
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| 419 | point.x = loc.x; |
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| 420 | point.y = loc.y; |
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| 421 | this.point = null; |
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| 422 | this.events.triggerEvent("unsnap", {point: point}); |
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| 423 | } |
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| 424 | }, |
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| 425 | |
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| 426 | /** |
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| 427 | * Method: testTarget |
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| 428 | * |
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| 429 | * Parameters: |
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| 430 | * target - {Object} Object with target layer configuration. |
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| 431 | * loc - {<OpenLayers.Geometry.Point>} The location of the mouse in map |
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| 432 | * coords. |
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| 433 | * |
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| 434 | * Returns: |
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| 435 | * {Object} A result object with rank, dist, x, and y properties. |
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| 436 | * Returns null if candidate is not eligible for snapping. |
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| 437 | */ |
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| 438 | testTarget: function(target, loc) { |
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| 439 | var tolerance = { |
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| 440 | node: this.getGeoTolerance(target.nodeTolerance), |
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| 441 | vertex: this.getGeoTolerance(target.vertexTolerance), |
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| 442 | edge: this.getGeoTolerance(target.edgeTolerance) |
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| 443 | }; |
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| 444 | // this could be cached if we don't support setting tolerance values directly |
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| 445 | var maxTolerance = Math.max( |
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| 446 | tolerance.node, tolerance.vertex, tolerance.edge |
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| 447 | ); |
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| 448 | var result = { |
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| 449 | rank: Number.POSITIVE_INFINITY, dist: Number.POSITIVE_INFINITY |
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| 450 | }; |
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| 451 | var eligible = false; |
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| 452 | var features = target.layer.features; |
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| 453 | var feature, type, vertices, vertex, closest, dist, found; |
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| 454 | var numTypes = this.precedence.length; |
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| 455 | var ll = new OpenLayers.LonLat(loc.x, loc.y); |
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| 456 | for(var i=0, len=features.length; i<len; ++i) { |
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| 457 | feature = features[i]; |
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| 458 | if(feature !== this.feature && !feature._sketch && |
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| 459 | feature.state !== OpenLayers.State.DELETE && |
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| 460 | (!target.filter || target.filter.evaluate(feature.attributes))) { |
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| 461 | if(feature.atPoint(ll, maxTolerance, maxTolerance)) { |
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| 462 | for(var j=0, stop=Math.min(result.rank+1, numTypes); j<stop; ++j) { |
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| 463 | type = this.precedence[j]; |
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| 464 | if(target[type]) { |
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| 465 | if(type === "edge") { |
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| 466 | closest = feature.geometry.distanceTo(loc, {details: true}); |
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| 467 | dist = closest.distance; |
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| 468 | if(dist <= tolerance[type] && dist < result.dist) { |
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| 469 | result = { |
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| 470 | rank: j, dist: dist, |
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| 471 | x: closest.x0, y: closest.y0 // closest coords on feature |
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| 472 | }; |
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| 473 | eligible = true; |
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| 474 | // don't look for lower precedence types for this feature |
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| 475 | break; |
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| 476 | } |
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| 477 | } else { |
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| 478 | // look for nodes or vertices |
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| 479 | vertices = feature.geometry.getVertices(type === "node"); |
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| 480 | found = false; |
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| 481 | for(var k=0, klen=vertices.length; k<klen; ++k) { |
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| 482 | vertex = vertices[k]; |
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| 483 | dist = vertex.distanceTo(loc); |
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| 484 | if(dist <= tolerance[type] && |
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| 485 | (j < result.rank || (j === result.rank && dist < result.dist))) { |
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| 486 | result = { |
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| 487 | rank: j, dist: dist, |
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| 488 | x: vertex.x, y: vertex.y |
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| 489 | }; |
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| 490 | eligible = true; |
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| 491 | found = true; |
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| 492 | } |
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| 493 | } |
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| 494 | if(found) { |
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| 495 | // don't look for lower precedence types for this feature |
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| 496 | break; |
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| 497 | } |
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| 498 | } |
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| 499 | } |
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| 500 | } |
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| 501 | } |
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| 502 | } |
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| 503 | } |
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| 504 | return eligible ? result : null; |
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| 505 | }, |
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| 506 | |
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| 507 | /** |
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| 508 | * Method: getGeoTolerance |
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| 509 | * Calculate a tolerance in map units given a tolerance in pixels. This |
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| 510 | * takes advantage of the <geoToleranceCache> when the map resolution |
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| 511 | * has not changed. |
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| 512 | * |
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| 513 | * Parameters: |
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| 514 | * tolerance - {Number} A tolerance value in pixels. |
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| 515 | * |
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| 516 | * Returns: |
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| 517 | * {Number} A tolerance value in map units. |
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| 518 | */ |
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| 519 | getGeoTolerance: function(tolerance) { |
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| 520 | var resolution = this.layer.map.getResolution(); |
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| 521 | if(resolution !== this.resolution) { |
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| 522 | this.resolution = resolution; |
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| 523 | this.geoToleranceCache = {}; |
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| 524 | } |
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| 525 | var geoTolerance = this.geoToleranceCache[tolerance]; |
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| 526 | if(geoTolerance === undefined) { |
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| 527 | geoTolerance = tolerance * resolution; |
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| 528 | this.geoToleranceCache[tolerance] = geoTolerance; |
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| 529 | } |
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| 530 | return geoTolerance; |
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| 531 | }, |
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| 532 | |
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| 533 | /** |
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| 534 | * Method: destroy |
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| 535 | * Clean up the control. |
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| 536 | */ |
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| 537 | destroy: function() { |
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| 538 | if(this.active) { |
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| 539 | this.deactivate(); // TODO: this should be handled by the super |
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| 540 | } |
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| 541 | delete this.layer; |
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| 542 | delete this.targets; |
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| 543 | OpenLayers.Control.prototype.destroy.call(this); |
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| 544 | }, |
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| 545 | |
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| 546 | CLASS_NAME: "OpenLayers.Control.Snapping" |
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| 547 | }); |
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