BlurFilter.js

/*
 * BlurFilter
 * Visit http://createjs.com/ for documentation, updates and examples.
 *
 * Copyright (c) 2010 gskinner.com, inc.
 * 
 * BoxBlur Algorithm by Mario Klingemann, quasimondo.com
 *
 * 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:
	/**
	 * Applies a box blur to DisplayObjects. Note that this filter is fairly CPU intensive, particularly if the quality is
	 * set higher than 1.
	 *
	 * <h4>Example</h4>
	 * This example creates a red circle, and then applies a 5 pixel blur to it. It uses the {{#crossLink "Filter/getBounds"}}{{/crossLink}}
	 * method to account for the spread that the blur causes.
	 *
	 *      var shape = new createjs.Shape().set({x:100,y:100});
	 *      shape.graphics.beginFill("#ff0000").drawCircle(0,0,50);
	 *
	 *      var blurFilter = new createjs.BlurFilter(5, 5, 1);
	 *      shape.filters = [blurFilter];
	 *      var bounds = blurFilter.getBounds();
	 *
	 *      shape.cache(-50+bounds.x, -50+bounds.y, 100+bounds.width, 100+bounds.height);
	 *
	 * See {{#crossLink "Filter"}}{{/crossLink}} for an more information on applying filters.
	 * @class BlurFilter
	 * @extends Filter
	 * @constructor
	 * @param {Number} [blurX=0] The horizontal blur radius in pixels.
	 * @param {Number} [blurY=0] The vertical blur radius in pixels.
	 * @param {Number} [quality=1] The number of blur iterations.
	 **/
	function BlurFilter( blurX, blurY, quality) {
		if ( isNaN(blurX) || blurX < 0 ) blurX = 0;
		if ( isNaN(blurY) || blurY < 0 ) blurY = 0;
		if ( isNaN(quality) || quality < 1  ) quality = 1;


		// public properties:
		/**
		 * Horizontal blur radius in pixels
		 * @property blurX
		 * @default 0
		 * @type Number
		 **/
		this.blurX = blurX | 0;

		/**
		 * Vertical blur radius in pixels
		 * @property blurY
		 * @default 0
		 * @type Number
		 **/
		this.blurY = blurY | 0;

		/**
		 * Number of blur iterations. For example, a value of 1 will produce a rough blur. A value of 2 will produce a
		 * smoother blur, but take twice as long to run.
		 * @property quality
		 * @default 1
		 * @type Number
		 **/
		this.quality = quality | 0;
	}
	var p = createjs.extend(BlurFilter, createjs.Filter);

	// TODO: deprecated
	// p.initialize = function() {}; // searchable for devs wondering where it is. REMOVED. See docs for details.


// constants:
	/**
	 * Array of multiply values for blur calculations.
	 * @property MUL_TABLE
	 * @type Array
	 * @protected
	 * @static
	 **/
	BlurFilter.MUL_TABLE = [1, 171, 205, 293, 57, 373, 79, 137, 241, 27, 391, 357, 41, 19, 283, 265, 497, 469, 443, 421, 25, 191, 365, 349, 335, 161, 155, 149, 9, 278, 269, 261, 505, 245, 475, 231, 449, 437, 213, 415, 405, 395, 193, 377, 369, 361, 353, 345, 169, 331, 325, 319, 313, 307, 301, 37, 145, 285, 281, 69, 271, 267, 263, 259, 509, 501, 493, 243, 479, 118, 465, 459, 113, 446, 55, 435, 429, 423, 209, 413, 51, 403, 199, 393, 97, 3, 379, 375, 371, 367, 363, 359, 355, 351, 347, 43, 85, 337, 333, 165, 327, 323, 5, 317, 157, 311, 77, 305, 303, 75, 297, 294, 73, 289, 287, 71, 141, 279, 277, 275, 68, 135, 67, 133, 33, 262, 260, 129, 511, 507, 503, 499, 495, 491, 61, 121, 481, 477, 237, 235, 467, 232, 115, 457, 227, 451, 7, 445, 221, 439, 218, 433, 215, 427, 425, 211, 419, 417, 207, 411, 409, 203, 202, 401, 399, 396, 197, 49, 389, 387, 385, 383, 95, 189, 47, 187, 93, 185, 23, 183, 91, 181, 45, 179, 89, 177, 11, 175, 87, 173, 345, 343, 341, 339, 337, 21, 167, 83, 331, 329, 327, 163, 81, 323, 321, 319, 159, 79, 315, 313, 39, 155, 309, 307, 153, 305, 303, 151, 75, 299, 149, 37, 295, 147, 73, 291, 145, 289, 287, 143, 285, 71, 141, 281, 35, 279, 139, 69, 275, 137, 273, 17, 271, 135, 269, 267, 133, 265, 33, 263, 131, 261, 130, 259, 129, 257, 1];

	/**
	 * Array of shift values for blur calculations.
	 * @property SHG_TABLE
	 * @type Array
	 * @protected
	 * @static
	 **/
	BlurFilter.SHG_TABLE = [0, 9, 10, 11, 9, 12, 10, 11, 12, 9, 13, 13, 10, 9, 13, 13, 14, 14, 14, 14, 10, 13, 14, 14, 14, 13, 13, 13, 9, 14, 14, 14, 15, 14, 15, 14, 15, 15, 14, 15, 15, 15, 14, 15, 15, 15, 15, 15, 14, 15, 15, 15, 15, 15, 15, 12, 14, 15, 15, 13, 15, 15, 15, 15, 16, 16, 16, 15, 16, 14, 16, 16, 14, 16, 13, 16, 16, 16, 15, 16, 13, 16, 15, 16, 14, 9, 16, 16, 16, 16, 16, 16, 16, 16, 16, 13, 14, 16, 16, 15, 16, 16, 10, 16, 15, 16, 14, 16, 16, 14, 16, 16, 14, 16, 16, 14, 15, 16, 16, 16, 14, 15, 14, 15, 13, 16, 16, 15, 17, 17, 17, 17, 17, 17, 14, 15, 17, 17, 16, 16, 17, 16, 15, 17, 16, 17, 11, 17, 16, 17, 16, 17, 16, 17, 17, 16, 17, 17, 16, 17, 17, 16, 16, 17, 17, 17, 16, 14, 17, 17, 17, 17, 15, 16, 14, 16, 15, 16, 13, 16, 15, 16, 14, 16, 15, 16, 12, 16, 15, 16, 17, 17, 17, 17, 17, 13, 16, 15, 17, 17, 17, 16, 15, 17, 17, 17, 16, 15, 17, 17, 14, 16, 17, 17, 16, 17, 17, 16, 15, 17, 16, 14, 17, 16, 15, 17, 16, 17, 17, 16, 17, 15, 16, 17, 14, 17, 16, 15, 17, 16, 17, 13, 17, 16, 17, 17, 16, 17, 14, 17, 16, 17, 16, 17, 16, 17, 9];

// public methods:
	/** docced in super class **/
	p.getBounds = function (rect) {
		var x = this.blurX|0, y = this.blurY| 0;
		if (x <= 0 && y <= 0) { return rect; }
		var q = Math.pow(this.quality, 0.2);
		return (rect || new createjs.Rectangle()).pad(x*q+1,y*q+1,x*q+1,y*q+1);
	};

	/** docced in super class **/
	p.clone = function() {
		return new BlurFilter(this.blurX, this.blurY, this.quality);
	};

	/** docced in super class **/
	p.toString = function() {
		return "[BlurFilter]";
	};


// private methods:

	/** docced in super class **/
	p._applyFilter = function (imageData) {

		premultiplyAlpha(imageData);

		var radiusX = this.blurX >> 1;
		if (isNaN(radiusX) || radiusX < 0) return false;
		var radiusY = this.blurY >> 1;
		if (isNaN(radiusY) || radiusY < 0) return false;
		if (radiusX == 0 && radiusY == 0) return false;

		var iterations = this.quality;
		if (isNaN(iterations) || iterations < 1) iterations = 1;
		iterations |= 0;
		if (iterations > 3) iterations = 3;
		if (iterations < 1) iterations = 1;

		var px = imageData.data;
		var x=0, y=0, i=0, p=0, yp=0, yi=0, yw=0, r=0, g=0, b=0, a=0, pr=0, pg=0, pb=0, pa=0;

		var divx = (radiusX + radiusX + 1) | 0;
		var divy = (radiusY + radiusY + 1) | 0;
		var w = imageData.width | 0;
		var h = imageData.height | 0;

		var w1 = (w - 1) | 0;
		var h1 = (h - 1) | 0;
		var rxp1 = (radiusX + 1) | 0;
		var ryp1 = (radiusY + 1) | 0;

		var ssx = {r:0,b:0,g:0,a:0};
		var sx = ssx;
		for ( i = 1; i < divx; i++ )
		{
			sx = sx.n = {r:0,b:0,g:0,a:0};
		}
		sx.n = ssx;

		var ssy = {r:0,b:0,g:0,a:0};
		var sy = ssy;
		for ( i = 1; i < divy; i++ )
		{
			sy = sy.n = {r:0,b:0,g:0,a:0};
		}
		sy.n = ssy;

		var si = null;


		var mtx = BlurFilter.MUL_TABLE[radiusX] | 0;
		var stx = BlurFilter.SHG_TABLE[radiusX] | 0;
		var mty = BlurFilter.MUL_TABLE[radiusY] | 0;
		var sty = BlurFilter.SHG_TABLE[radiusY] | 0;

		while (iterations-- > 0) {

			yw = yi = 0;
			var ms = mtx;
			var ss = stx;
			for (y = h; --y > -1;) {
				r = rxp1 * (pr = px[(yi) | 0]);
				g = rxp1 * (pg = px[(yi + 1) | 0]);
				b = rxp1 * (pb = px[(yi + 2) | 0]);
				a = rxp1 * (pa = px[(yi + 3) | 0]);

				sx = ssx;

				for( i = rxp1; --i > -1; )
				{
					sx.r = pr;
					sx.g = pg;
					sx.b = pb;
					sx.a = pa;
					sx = sx.n;
				}

				for( i = 1; i < rxp1; i++ )
				{
					p = (yi + ((w1 < i ? w1 : i) << 2)) | 0;
					r += ( sx.r = px[p]);
					g += ( sx.g = px[p+1]);
					b += ( sx.b = px[p+2]);
					a += ( sx.a = px[p+3]);

					sx = sx.n;
				}

				si = ssx;
				for ( x = 0; x < w; x++ )
				{
					px[yi++] = (r * ms) >>> ss;
					px[yi++] = (g * ms) >>> ss;
					px[yi++] = (b * ms) >>> ss;
					px[yi++] = (a * ms) >>> ss;

					p = ((yw + ((p = x + radiusX + 1) < w1 ? p : w1)) << 2);

					r -= si.r - ( si.r = px[p]);
					g -= si.g - ( si.g = px[p+1]);
					b -= si.b - ( si.b = px[p+2]);
					a -= si.a - ( si.a = px[p+3]);

					si = si.n;

				}
				yw += w;
			}

			ms = mty;
			ss = sty;
			for (x = 0; x < w; x++) {
				yi = (x << 2) | 0;

				r = (ryp1 * (pr = px[yi])) | 0;
				g = (ryp1 * (pg = px[(yi + 1) | 0])) | 0;
				b = (ryp1 * (pb = px[(yi + 2) | 0])) | 0;
				a = (ryp1 * (pa = px[(yi + 3) | 0])) | 0;

				sy = ssy;
				for( i = 0; i < ryp1; i++ )
				{
					sy.r = pr;
					sy.g = pg;
					sy.b = pb;
					sy.a = pa;
					sy = sy.n;
				}

				yp = w;

				for( i = 1; i <= radiusY; i++ )
				{
					yi = ( yp + x ) << 2;

					r += ( sy.r = px[yi]);
					g += ( sy.g = px[yi+1]);
					b += ( sy.b = px[yi+2]);
					a += ( sy.a = px[yi+3]);

					sy = sy.n;

					if( i < h1 )
					{
						yp += w;
					}
				}

				yi = x;
				si = ssy;
				if ( iterations > 0 )
				{
					for ( y = 0; y < h; y++ )
					{
						p = yi << 2;
						px[p]   = (r * ms) >>> ss;
						px[p+1] = (g * ms) >>> ss;
						px[p+2] = (b * ms) >>> ss;
						px[p+3] = (a * ms) >>> ss;

						p = ( x + (( ( p = y + ryp1) < h1 ? p : h1 ) * w )) << 2;

						r -= si.r - ( si.r = px[p]);
						g -= si.g - ( si.g = px[p+1]);
						b -= si.b - ( si.b = px[p+2]);
						a -= si.a - ( si.a = px[p+3]);

						si = si.n;

						yi += w;
					}
				} else {
					for ( y = 0; y < h; y++ )
					{
						p = yi << 2;
						px[p]   = (r * ms) >>> ss;
						px[p+1] = (g * ms) >>> ss;
						px[p+2] = (b * ms) >>> ss;
						px[p+3] = (a * ms) >>> ss;

						p = ( x + (( ( p = y + ryp1) < h1 ? p : h1 ) * w )) << 2;

						r -= si.r - ( si.r = px[p]);
						g -= si.g - ( si.g = px[p+1]);
						b -= si.b - ( si.b = px[p+2]);
						a -= si.a - ( si.a = px[p+3]);

						si = si.n;

						yi += w;
					}
				}
			}

		}
		
		unpremultiplyAlpha(imageData);
		
		return true;
	};
	
	function premultiplyAlpha(imageData)
	{
		var pixels = imageData.data;
		var size = imageData.width * imageData.height * 4;
		
		for (var i=0; i<size; i+=4)
		{
			var a = pixels[i+3] / 255;
			pixels[i  ] *= a;
			pixels[i+1] *= a;
			pixels[i+2] *= a;
		}
	}
	
	function unpremultiplyAlpha(imageData)
	{
		var pixels = imageData.data;
		var size = imageData.width * imageData.height * 4;
		
		for (var i=0; i<size; i+=4)
		{
			var a = pixels[i+3];
			if (a != 0)
			{
				a = 255 / a;
				pixels[i  ] *= a;
				pixels[i+1] *= a;
				pixels[i+2] *= a;
			}
		}
	} 
	
	createjs.BlurFilter = createjs.promote(BlurFilter, "Filter");
}());