107 lines
2.4 KiB
JavaScript
107 lines
2.4 KiB
JavaScript
goog.provide('ol.ImageCanvas');
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goog.require('goog.asserts');
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goog.require('ol.ImageBase');
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goog.require('ol.ImageState');
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/**
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* @constructor
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* @extends {ol.ImageBase}
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* @param {ol.Extent} extent Extent.
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* @param {number} resolution Resolution.
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* @param {number} pixelRatio Pixel ratio.
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* @param {Array.<ol.Attribution>} attributions Attributions.
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* @param {HTMLCanvasElement} canvas Canvas.
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* @param {ol.ImageCanvasLoader=} opt_loader Optional loader function to
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* support asynchronous canvas drawing.
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*/
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ol.ImageCanvas = function(extent, resolution, pixelRatio, attributions,
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canvas, opt_loader) {
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/**
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* Optional canvas loader function.
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* @type {?ol.ImageCanvasLoader}
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* @private
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*/
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this.loader_ = opt_loader !== undefined ? opt_loader : null;
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var state = opt_loader !== undefined ?
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ol.ImageState.IDLE : ol.ImageState.LOADED;
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goog.base(this, extent, [resolution, resolution], pixelRatio, state,
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attributions);
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/**
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* @private
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* @type {HTMLCanvasElement}
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*/
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this.canvas_ = canvas;
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/**
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* @private
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* @type {Error}
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*/
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this.error_ = null;
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};
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goog.inherits(ol.ImageCanvas, ol.ImageBase);
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/**
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* Get any error associated with asynchronous rendering.
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* @return {Error} Any error that occurred during rendering.
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*/
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ol.ImageCanvas.prototype.getError = function() {
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return this.error_;
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};
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/**
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* Handle async drawing complete.
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* @param {Error} err Any error during drawing.
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* @private
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*/
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ol.ImageCanvas.prototype.handleLoad_ = function(err) {
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if (err) {
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this.error_ = err;
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this.state = ol.ImageState.ERROR;
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} else {
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this.state = ol.ImageState.LOADED;
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}
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this.changed();
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};
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/**
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* Trigger drawing on canvas.
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*/
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ol.ImageCanvas.prototype.load = function() {
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if (this.state == ol.ImageState.IDLE) {
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goog.asserts.assert(this.loader_, 'this.loader_ must be set');
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this.state = ol.ImageState.LOADING;
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this.changed();
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this.loader_(goog.bind(this.handleLoad_, this));
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}
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};
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/**
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* @inheritDoc
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*/
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ol.ImageCanvas.prototype.getImage = function(opt_context) {
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return this.canvas_;
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};
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/**
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* A function that is called to trigger asynchronous canvas drawing. It is
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* called with a "done" callback that should be called when drawing is done.
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* If any error occurs during drawing, the "done" callback should be called with
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* that error.
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*
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* @typedef {function(function(Error))}
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*/
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ol.ImageCanvasLoader;
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