48 lines
1.6 KiB
JavaScript
48 lines
1.6 KiB
JavaScript
goog.provide('ol.render');
|
|
|
|
goog.require('goog.vec.Mat4');
|
|
goog.require('ol.render.canvas.Immediate');
|
|
goog.require('ol.vec.Mat4');
|
|
|
|
|
|
/**
|
|
* Binds a Canvas Immediate API to a canvas context, to allow drawing geometries
|
|
* to the context's canvas.
|
|
*
|
|
* The units for geometry coordinates are css pixels relative to the top left
|
|
* corner of the canvas element.
|
|
* ```js
|
|
* var canvas = document.createElement('canvas');
|
|
* var render = ol.render.toContext(canvas.getContext('2d'),
|
|
* { size: [100, 100] });
|
|
* render.setFillStrokeStyle(new ol.style.Fill({ color: blue }));
|
|
* render.drawPolygon(
|
|
* new ol.geom.Polygon([[[0, 0], [100, 100], [100, 0], [0, 0]]]));
|
|
* ```
|
|
*
|
|
* Note that {@link ol.render.canvas.Immediate#drawAsync} and
|
|
* {@link ol.render.canvas.Immediate#drawFeature} cannot be used.
|
|
*
|
|
* @param {CanvasRenderingContext2D} context Canvas context.
|
|
* @param {olx.render.ToContextOptions=} opt_options Options.
|
|
* @return {ol.render.canvas.Immediate} Canvas Immediate.
|
|
* @api
|
|
*/
|
|
ol.render.toContext = function(context, opt_options) {
|
|
var canvas = context.canvas;
|
|
var options = opt_options ? opt_options : {};
|
|
var pixelRatio = options.pixelRatio || ol.has.DEVICE_PIXEL_RATIO;
|
|
var size = options.size;
|
|
if (size) {
|
|
canvas.width = size[0] * pixelRatio;
|
|
canvas.height = size[1] * pixelRatio;
|
|
canvas.style.width = size[0] + 'px';
|
|
canvas.style.height = size[1] + 'px';
|
|
}
|
|
var extent = [0, 0, canvas.width, canvas.height];
|
|
var transform = ol.vec.Mat4.makeTransform2D(goog.vec.Mat4.createNumber(),
|
|
0, 0, pixelRatio, pixelRatio, 0, 0, 0);
|
|
return new ol.render.canvas.Immediate(context, pixelRatio, extent, transform,
|
|
0);
|
|
};
|