/*
* AlphaMaskFilter
* 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:
/**
* Applies the alpha from the mask image (or canvas) to the target, such that the alpha channel of the result will
* be derived from the mask, and the RGB channels will be copied from the target. This can be used, for example, to
* apply an alpha mask to a display object. This can also be used to combine a JPG compressed RGB image with a PNG32
* alpha mask, which can result in a much smaller file size than a single PNG32 containing ARGB.
*
* IMPORTANT NOTE: This filter currently does not support the targetCtx, or targetX/Y parameters correctly.
*
*
Example
* This example draws a gradient box, then caches it and uses the "cacheCanvas" as the alpha mask on a 100x100 image.
*
* var box = new createjs.Shape();
* box.graphics.beginLinearGradientFill(["#000000", "rgba(0, 0, 0, 0)"], [0, 1], 0, 0, 100, 100)
* box.graphics.drawRect(0, 0, 100, 100);
* box.cache(0, 0, 100, 100);
*
* var bmp = new createjs.Bitmap("path/to/image.jpg");
* bmp.filters = [
* new createjs.AlphaMaskFilter(box.cacheCanvas)
* ];
* bmp.cache(0, 0, 100, 100);
*
* See {{#crossLink "Filter"}}{{/crossLink}} for more information on applying filters.
* @class AlphaMaskFilter
* @extends Filter
* @constructor
* @param {HTMLImageElement|HTMLCanvasElement|WebGLTexture} mask
**/
function AlphaMaskFilter(mask) {
this.Filter_constructor();
if (!createjs.Filter.isValidImageSource(mask)) {
throw "Must provide valid image source for alpha mask, see Filter.isValidImageSource";
}
// public properties:
/**
* The image (or canvas) to use as the mask.
* @property mask
* @type HTMLImageElement|HTMLCanvasElement
**/
this.mask = mask;
// Docced in superclass
this.usesContext = true;
this.FRAG_SHADER_BODY = (
"uniform sampler2D uAlphaSampler;"+
"void main(void) {" +
"vec4 color = texture2D(uSampler, vTextureCoord);" +
"vec4 alphaMap = texture2D(uAlphaSampler, vTextureCoord);" +
"gl_FragColor = vec4(color.rgb * alphaMap.a, color.a * alphaMap.a);" +
"}"
);
}
var p = createjs.extend(AlphaMaskFilter, createjs.Filter);
// TODO: deprecated
// p.initialize = function() {}; // searchable for devs wondering where it is. REMOVED. See docs for details.
// Docced in superclass
p.shaderParamSetup = function(gl, stage, shaderProgram) {
if(!this._mapTexture) { this._mapTexture = gl.createTexture(); }
gl.activeTexture(gl.TEXTURE1);
gl.bindTexture(gl.TEXTURE_2D, this._mapTexture);
stage.setTextureParams(gl);
if (this.mask !== this._mapTexture) {
gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, this.mask);
}
gl.uniform1i(
gl.getUniformLocation(shaderProgram, "uAlphaSampler"),
1
);
};
// public methods:
/**
* Applies the filter to the specified context.
*
* IMPORTANT NOTE: This filter currently does not support the targetCtx, or targetX/Y parameters
* correctly.
* @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.
* @return {Boolean} If the filter was applied successfully.
**/
p.applyFilter = function (ctx, x, y, width, height, targetCtx) {
if (!this.mask) { return true; }
if (targetCtx === undefined) { targetCtx = ctx; }
if (targetCtx !== ctx) {
targetCtx.drawImage(ctx.canvas,
0, 0, ctx.canvas.width, ctx.canvas.height,
0, 0, targetCtx.canvas.width, targetCtx.canvas.height
);
}
targetCtx.save();
targetCtx.globalCompositeOperation = "destination-in";
targetCtx.drawImage(this.mask, 0,0, this.mask.width,this.mask.height, x,y, width,height);
targetCtx.restore();
return true;
};
// Docced in superclass
p.clone = function () {
return new AlphaMaskFilter(this.mask);
};
// Docced in superclass
p.toString = function () {
return "[AlphaMaskFilter]";
};
createjs.AlphaMaskFilter = createjs.promote(AlphaMaskFilter, "Filter");
}());