#

API Documentation for: 0.8.1
Show: Inherited Protected Private Deprecated

# File:Filter.js

    /*
    * Filter
    * Visit http://createjs.com/ for documentation, updates and examples.
    *
    * Copyright (c) 2010 gskinner.com, inc.
    *
    * Permission is hereby granted, free of charge, to any person
    * obtaining a copy of this software and associated documentation
    * files (the "Software"), to deal in the Software without
    * restriction, including without limitation the rights to use,
    * copy, modify, merge, publish, distribute, sublicense, and/or sell
    * copies of the Software, and to permit persons to whom the
    * Software is furnished to do so, subject to the following
    * conditions:
    *
    * The above copyright notice and this permission notice shall be
    * included in all copies or substantial portions of the Software.
    *
    * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
    * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
    * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
    * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
    * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
    * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
    * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
    * OTHER DEALINGS IN THE SOFTWARE.
    */

    /**
     * @module EaselJS
     */

    // namespace:
    //this.createjs = this.createjs||{};

    (function() {
    	"use strict";

    // constructor:
    	/**
    	 * Base class that all filters should inherit from. Filters need to be applied to objects that have been cached using
    	 * the {{#crossLink "DisplayObject/cache"}}{{/crossLink}} method. If an object changes, please cache it again, or use
    	 * {{#crossLink "DisplayObject/updateCache"}}{{/crossLink}}. Note that the filters must be applied before caching.
    	 *
    	 * <h4>Example</h4>
    	 *
    	 *      myInstance.filters = [
    	 *          new createjs.ColorFilter(0, 0, 0, 1, 255, 0, 0),
    	 *          new createjs.BlurFilter(5, 5, 10)
    	 *      ];
    	 *      myInstance.cache(0,0, 100, 100);
    	 *
    	 * Note that each filter can implement a {{#crossLink "Filter/getBounds"}}{{/crossLink}} method, which returns the
    	 * margins that need to be applied in order to fully display the filter. For example, the {{#crossLink "BlurFilter"}}{{/crossLink}}
    	 * will cause an object to feather outwards, resulting in a margin around the shape.
    	 *
    	 * <h4>EaselJS Filters</h4>
    	 * EaselJS comes with a number of pre-built filters. Note that individual filters are not compiled into the minified
    	 * version of EaselJS. To use them, you must include them manually in the HTML.
    	 * <ul><li>{{#crossLink "AlphaMapFilter"}}{{/crossLink}} : Map a greyscale image to the alpha channel of a display object</li>
    	 *      <li>{{#crossLink "AlphaMaskFilter"}}{{/crossLink}}: Map an image's alpha channel to the alpha channel of a display object</li>
    	 *      <li>{{#crossLink "BlurFilter"}}{{/crossLink}}: Apply vertical and horizontal blur to a display object</li>
    	 *      <li>{{#crossLink "ColorFilter"}}{{/crossLink}}: Color transform a display object</li>
    	 *      <li>{{#crossLink "ColorMatrixFilter"}}{{/crossLink}}: Transform an image using a {{#crossLink "ColorMatrix"}}{{/crossLink}}</li>
    	 * </ul>
    	 *
    	 * @class Filter
    	 * @constructor
    	 **/
    	function Filter() {}
    	var p = Filter.prototype;

    	/**
    	 * <strong>REMOVED</strong>. Removed in favor of using `MySuperClass_constructor`.
    	 * See {{#crossLink "Utility Methods/extend"}}{{/crossLink}} and {{#crossLink "Utility Methods/promote"}}{{/crossLink}}
    	 * for details.
    	 *
    	 * There is an inheritance tutorial distributed with EaselJS in /tutorials/Inheritance.
    	 *
    	 * @method initialize
    	 * @protected
    	 * @deprecated
    	 */
    	// p.initialize = function() {}; // searchable for devs wondering where it is.

    // public methods:
    	/**
    	 * Provides padding values for this filter. That is, how much the filter will extend the visual bounds of an object it is applied to.
    	 * @method getBounds
    	 * @param {Rectangle} [rect] If specified, the provided Rectangle instance will be expanded by the padding amounts and returned.
    	 * @return {Rectangle} If a `rect` param was provided, it is returned. If not, either a new rectangle with the padding values, or null if no padding is required for this filter.
    	 **/
    	p.getBounds = function(rect) {
    		return rect;
    	};

    	/**
    	 * Applies the filter to the specified context.
    	 * @method applyFilter
    	 * @param {CanvasRenderingContext2D} ctx The 2D context to use as the source.
    	 * @param {Number} x The x position to use for the source rect.
    	 * @param {Number} y The y position to use for the source rect.
    	 * @param {Number} width The width to use for the source rect.
    	 * @param {Number} height The height to use for the source rect.
    	 * @param {CanvasRenderingContext2D} [targetCtx] The 2D context to draw the result to. Defaults to the context passed to ctx.
    	 * @param {Number} [targetX] The x position to draw the result to. Defaults to the value passed to x.
    	 * @param {Number} [targetY] The y position to draw the result to. Defaults to the value passed to y.
    	 * @return {Boolean} If the filter was applied successfully.
    	 **/
    	p.applyFilter = function(ctx, x, y, width, height, targetCtx, targetX, targetY) {
    		// this is the default behaviour because most filters access pixel data. It is overridden when not needed.
    		targetCtx = targetCtx || ctx;
    		if (targetX == null) { targetX = x; }
    		if (targetY == null) { targetY = y; }
    		try {
    			var imageData = ctx.getImageData(x, y, width, height);
    		} catch (e) {
    			return false;
    		}
    		if (this._applyFilter(imageData)) {
    			targetCtx.putImageData(imageData, targetX, targetY);
    			return true;
    		}
    		return false;
    	};

    	/**
    	 * Returns a string representation of this object.
    	 * @method toString
    	 * @return {String} a string representation of the instance.
    	 **/
    	p.toString = function() {
    		return "[Filter]";
    	};

    	/**
    	 * Returns a clone of this Filter instance.
    	 * @method clone
    	 * @return {Filter} A clone of the current Filter instance.
    	 **/
    	p.clone = function() {
    		return new Filter();
    	};

    // private methods:
    	/**
    	 * @method _applyFilter
    	 * @param {ImageData} imageData Target ImageData instance.
    	 * @return {Boolean}
    	 **/
    	p._applyFilter = function(imageData) { return true; };

    	createjs.Filter = Filter;
    }());