/* Copyright (c) 2006-2010 by OpenLayers Contributors (see authors.txt for
* full list of contributors). Published under the Clear BSD license.
* See http://svn.openlayers.org/trunk/openlayers/license.txt for the
* full text of the license. */
/**
* Class: OpenLayers.Renderer
* This is the base class for all renderers.
*
* This is based on a merger code written by Paul Spencer and Bertil Chapuis.
* It is largely composed of virtual functions that are to be implemented
* in technology-specific subclasses, but there is some generic code too.
*
* The functions that *are* implemented here merely deal with the maintenance
* of the size and extent variables, as well as the cached 'resolution'
* value.
*
* A note to the user that all subclasses should use getResolution() instead
* of directly accessing this.resolution in order to correctly use the
* cacheing system.
*
*/
OpenLayers.Renderer = OpenLayers.Class({
/**
* Property: container
* {DOMElement}
*/
container: null,
/**
* Property: root
* {DOMElement}
*/
root: null,
/**
* Property: extent
* {<OpenLayers.Bounds>}
*/
extent: null,
/**
* Property: locked
* {Boolean} If the renderer is currently in a state where many things
* are changing, the 'locked' property is set to true. This means
* that renderers can expect at least one more drawFeature event to be
* called with the 'locked' property set to 'true': In some renderers,
* this might make sense to use as a 'only update local information'
* flag.
*/
locked: false,
/**
* Property: size
* {<OpenLayers.Size>}
*/
size: null,
/**
* Property: resolution
* {Float} cache of current map resolution
*/
resolution: null,
/**
* Property: map
* {<OpenLayers.Map>} Reference to the map -- this is set in Vector's setMap()
*/
map: null,
/**
* Constructor: OpenLayers.Renderer
*
* Parameters:
* containerID - {<String>}
* options - {Object} options for this renderer. See sublcasses for
* supported options.
*/
initialize: function(containerID, options) {
this.container = OpenLayers.Util.getElement(containerID);
},
/**
* APIMethod: destroy
*/
destroy: function() {
this.container = null;
this.extent = null;
this.size = null;
this.resolution = null;
this.map = null;
},
/**
* APIMethod: supported
* This should be overridden by specific subclasses
*
* Returns:
* {Boolean} Whether or not the browser supports the renderer class
*/
supported: function() {
return false;
},
/**
* Method: setExtent
* Set the visible part of the layer.
*
* Resolution has probably changed, so we nullify the resolution
* cache (this.resolution) -- this way it will be re-computed when
* next it is needed.
* We nullify the resolution cache (this.resolution) if resolutionChanged
* is set to true - this way it will be re-computed on the next
* getResolution() request.
*
* Parameters:
* extent - {<OpenLayers.Bounds>}
* resolutionChanged - {Boolean}
*/
setExtent: function(extent, resolutionChanged) {
this.extent = extent.clone();
if (resolutionChanged) {
this.resolution = null;
}
},
/**
* Method: setSize
* Sets the size of the drawing surface.
*
* Resolution has probably changed, so we nullify the resolution
* cache (this.resolution) -- this way it will be re-computed when
* next it is needed.
*
* Parameters:
* size - {<OpenLayers.Size>}
*/
setSize: function(size) {
this.size = size.clone();
this.resolution = null;
},
/**
* Method: getResolution
* Uses cached copy of resolution if available to minimize computing
*
* Returns:
* The current map's resolution
*/
getResolution: function() {
this.resolution = this.resolution || this.map.getResolution();
return this.resolution;
},
/**
* Method: drawFeature
* Draw the feature. The optional style argument can be used
* to override the feature's own style. This method should only
* be called from layer.drawFeature().
*
* Parameters:
* feature - {<OpenLayers.Feature.Vector>}
* style - {<Object>}
*
* Returns:
* {Boolean} true if the feature has been drawn completely, false if not,
* undefined if the feature had no geometry
*/
drawFeature: function(feature, style) {
if(style == null) {
style = feature.style;
}
if (feature.geometry) {
var bounds = feature.geometry.getBounds();
if(bounds) {
if (!bounds.intersectsBounds(this.extent)) {
style = {display: "none"};
}
var rendered = this.drawGeometry(feature.geometry, style, feature.id);
if(style.display != "none" && style.label && rendered !== false) {
var location = feature.geometry.getCentroid();
if(style.labelXOffset || style.labelYOffset) {
xOffset = isNaN(style.labelXOffset) ? 0 : style.labelXOffset;
yOffset = isNaN(style.labelYOffset) ? 0 : style.labelYOffset;
var res = this.getResolution();
location.move(xOffset*res, yOffset*res);
}
this.drawText(feature.id, style, location);
} else {
this.removeText(feature.id);
}
return rendered;
}
}
},
/**
* Method: drawGeometry
*
* Draw a geometry. This should only be called from the renderer itself.
* Use layer.drawFeature() from outside the renderer.
* virtual function
*
* Parameters:
* geometry - {<OpenLayers.Geometry>}
* style - {Object}
* featureId - {<String>}
*/
drawGeometry: function(geometry, style, featureId) {},
/**
* Method: drawText
* Function for drawing text labels.
* This method is only called by the renderer itself.
*
* Parameters:
* featureId - {String}
* style -
* location - {<OpenLayers.Geometry.Point>}
*/
drawText: function(featureId, style, location) {},
/**
* Method: removeText
* Function for removing text labels.
* This method is only called by the renderer itself.
*
* Parameters:
* featureId - {String}
*/
removeText: function(featureId) {},
/**
* Method: clear
* Clear all vectors from the renderer.
* virtual function.
*/
clear: function() {},
/**
* Method: getFeatureIdFromEvent
* Returns a feature id from an event on the renderer.
* How this happens is specific to the renderer. This should be
* called from layer.getFeatureFromEvent().
* Virtual function.
*
* Parameters:
* evt - {<OpenLayers.Event>}
*
* Returns:
* {String} A feature id or null.
*/
getFeatureIdFromEvent: function(evt) {},
/**
* Method: eraseFeatures
* This is called by the layer to erase features
*
* Parameters:
* features - {Array(<OpenLayers.Feature.Vector>)}
*/
eraseFeatures: function(features) {
if(!(features instanceof Array)) {
features = [features];
}
for(var i=0, len=features.length; i<len; ++i) {
var feature = features[i];
this.eraseGeometry(feature.geometry, feature.id);
this.removeText(feature.id);
}
},
/**
* Method: eraseGeometry
* Remove a geometry from the renderer (by id).
* virtual function.
*
* Parameters:
* geometry - {<OpenLayers.Geometry>}
* featureId - {String}
*/
eraseGeometry: function(geometry, featureId) {},
/**
* Method: moveRoot
* moves this renderer's root to a (different) renderer.
* To be implemented by subclasses that require a common renderer root for
* feature selection.
*
* Parameters:
* renderer - {<OpenLayers.Renderer>} target renderer for the moved root
*/
moveRoot: function(renderer) {},
/**
* Method: getRenderLayerId
* Gets the layer that this renderer's output appears on. If moveRoot was
* used, this will be different from the id of the layer containing the
* features rendered by this renderer.
*
* Returns:
* {String} the id of the output layer.
*/
getRenderLayerId: function() {
return this.container.id;
},
/**
* Method: applyDefaultSymbolizer
*
* Parameters:
* symbolizer - {Object}
*
* Returns:
* {Object}
*/
applyDefaultSymbolizer: function(symbolizer) {
var result = OpenLayers.Util.extend({},
OpenLayers.Renderer.defaultSymbolizer);
if(symbolizer.stroke === false) {
delete result.strokeWidth;
delete result.strokeColor;
}
if(symbolizer.fill === false) {
delete result.fillColor;
}
OpenLayers.Util.extend(result, symbolizer);
return result;
},
CLASS_NAME: "OpenLayers.Renderer"
});
/**
* Constant: OpenLayers.Renderer.defaultSymbolizer
* {Object} Properties from this symbolizer will be applied to symbolizers
* with missing properties. This can also be used to set a global
* symbolizer default in OpenLayers. To be SLD 1.x compliant, add the
* following code before rendering any vector features:
* (code)
* OpenLayers.Renderer.defaultSymbolizer = {
* fillColor: "#808080",
* fillOpacity: 1,
* strokeColor: "#000000",
* strokeOpacity: 1,
* strokeWidth: 1,
* pointRadius: 3,
* graphicName: "square"
* };
* (end)
*/
OpenLayers.Renderer.defaultSymbolizer = {
fillColor: "#000000",
strokeColor: "#000000",
strokeWidth: 2,
fillOpacity: 1,
strokeOpacity: 1,
pointRadius: 0
};