ashatora/openlayers
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Added support for named graphics to Canvas renderer

Browse Source
This commit is contained in:
Arjen Kopinga
2012-02-22 15:26:21 +01:00
parent a569873ff1
commit d6e28e5ab9
1 changed files with 153 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

153
lib/OpenLayers/Renderer/Canvas.js
View File

@@ -51,6 +51,12 @@ OpenLayers.Renderer.Canvas = OpenLayers.Class(OpenLayers.Renderer, {
*/
pendingRedraw: false,
/**
* Property: cachedSymbolBounds
* {Object} Internal cache of calculated symbol extents.
*/
cachedSymbolBounds: {},
/**
* Constructor: OpenLayers.Renderer.Canvas
*
@@ -283,6 +289,151 @@ OpenLayers.Renderer.Canvas = OpenLayers.Class(OpenLayers.Renderer, {
img.src = style.externalGraphic;
},
/**
* Method: drawNamedSymbol
* Called to draw Well Known Graphic Symbol Name.
* This method is only called by the renderer itself.
*
* Parameters:
* geometry - {<OpenLayers.Geometry>}
* style - {Object}
* featureId - {String}
*/
drawNamedSymbol: function(geometry, style, featureId) {
var x, y, cx, cy, i, symbolBounds, scaling, angle;
var unscaledStrokeWidth;
var deg2rad = Math.PI / 180.0;
var symbol = OpenLayers.Renderer.symbol[style.graphicName];
if (!symbol) {
throw new Error(style.graphicName + ' is not a valid symbol name');
}
if (!symbol.length || symbol.length < 2) return;
var pt = this.getLocalXY(geometry);
var p0 = pt[0];
var p1 = pt[1];
if (isNaN(p0) || isNaN(p1)) return;
// Use rounded line caps
this.canvas.lineCap = "round";
this.canvas.lineJoin = "round";
// Scale and rotate symbols, using precalculated bounds whenever possible.
if (style.graphicName in this.cachedSymbolBounds) {
symbolBounds = this.cachedSymbolBounds[style.graphicName];
} else {
symbolBounds = new OpenLayers.Bounds();
for(i = 0; i < symbol.length; i+=2) {
symbolBounds.extend(new OpenLayers.LonLat(symbol[i], symbol[i+1]));
}
this.cachedSymbolBounds[style.graphicName] = symbolBounds;
}
// Push symbol scaling, translation and rotation onto the transformation stack in reverse order.
// Don't forget to apply all canvas transformations to the hitContext canvas as well(!)
this.canvas.save();
if (this.hitDetection) this.hitContext.save();
// Step 3: place symbol at the desired location
this.canvas.translate(p0,p1);
if (this.hitDetection) this.hitContext.translate(p0,p1);
// Step 2a. rotate the symbol if necessary
angle = deg2rad * style.rotation; // will be NaN when style.rotation is undefined.
if (!isNaN(angle)) {
this.canvas.rotate(angle);
if (this.hitDetection) this.hitContext.rotate(angle);
}
// // Step 2: scale symbol such that pointRadius equals half the maximum symbol dimension.
scaling = 2.0 * style.pointRadius / Math.max(symbolBounds.getWidth(), symbolBounds.getHeight());
this.canvas.scale(scaling,scaling);
if (this.hitDetection) this.hitContext.scale(scaling,scaling);
// Step 1: center the symbol at the origin
cx = symbolBounds.getCenterLonLat().lon;
cy = symbolBounds.getCenterLonLat().lat;
this.canvas.translate(-cx,-cy);
if (this.hitDetection) this.hitContext.translate(-cx,-cy);
// Don't forget to scale stroke widths, because they are affected by canvas scale transformations as well(!)
// Alternative: scale symbol coordinates manually, so stroke width scaling is not needed anymore.
unscaledStrokeWidth = style.strokeWidth;
style.strokeWidth = unscaledStrokeWidth / scaling;
if (style.fill !== false) {
this.setCanvasStyle("fill", style);
this.canvas.beginPath();
for (i=0; i<symbol.length; i=i+2) {
x = symbol[i];
y = symbol[i+1];
if (i == 0) this.canvas.moveTo(x,y);
this.canvas.lineTo(x,y);
}
this.canvas.closePath();
this.canvas.fill();
if (this.hitDetection) {
this.setHitContextStyle("fill", featureId, style);
this.hitContext.beginPath();
for (i=0; i<symbol.length; i=i+2) {
x = symbol[i];
y = symbol[i+1];
if (i == 0) this.canvas.moveTo(x,y);
this.hitContext.lineTo(x,y);
}
this.hitContext.closePath();
this.hitContext.fill();
}
}
if (style.stroke !== false) {
this.setCanvasStyle("stroke", style);
this.canvas.beginPath();
for (i=0; i<symbol.length; i=i+2) {
x = symbol[i];
y = symbol[i+1];
if (i == 0) this.canvas.moveTo(x,y);
this.canvas.lineTo(x,y);
}
this.canvas.closePath();
this.canvas.stroke();
}
style.strokeWidth = unscaledStrokeWidth;
this.canvas.restore();
if (this.hitDetection) this.hitContext.restore();
this.setCanvasStyle("reset");
},
/**
* Method: setCanvasStyle
* Prepare the canvas for drawing by setting various global settings.
*
* Parameters:
* type - {String} one of 'stroke', 'fill', or 'reset'
* style - {Object} Symbolizer hash
*/
setCanvasStyle: function(type, style) {
if (type === "fill") {
this.canvas.globalAlpha = style['fillOpacity'];
this.canvas.fillStyle = style['fillColor'];
} else if (type === "stroke") {
this.canvas.globalAlpha = style['strokeOpacity'];
this.canvas.strokeStyle = style['strokeColor'];
this.canvas.lineWidth = style['strokeWidth'];
} else {
this.canvas.globalAlpha = 0;
this.canvas.lineWidth = 1;
}
},
/**
* Method: setCanvasStyle
* Prepare the canvas for drawing by setting various global settings.
@@ -365,6 +516,8 @@ OpenLayers.Renderer.Canvas = OpenLayers.Class(OpenLayers.Renderer, {
if(style.graphic !== false) {
if(style.externalGraphic) {
this.drawExternalGraphic(geometry, style, featureId);
} else if (style.graphicName && (style.graphicName != "circle")) {
this.drawNamedSymbol(geometry, style, featureId);
} else {
var pt = this.getLocalXY(geometry);
var p0 = pt[0];