piskel/js/utils/FrameUtils.js

96 lines
3 KiB
JavaScript

(function () {
var ns = $.namespace('pskl.utils');
var colorCache = {};
ns.FrameUtils = {
merge : function (frames) {
var merged = null;
if (frames.length) {
merged = frames[0];
var w = merged.getWidth(), h = merged.getHeight();
for (var i = 1 ; i < frames.length ; i++) {
pskl.utils.FrameUtils.mergeFrames_(merged, frames[i]);
}
}
return merged;
},
mergeFrames_ : function (frameA, frameB) {
frameB.forEachPixel(function (p, col, row) {
if (p != Constants.TRANSPARENT_COLOR) {
frameA.setPixel(col, row, p);
}
});
},
/**
* Alpha compositing using porter duff algorithm :
* http://en.wikipedia.org/wiki/Alpha_compositing
* http://keithp.com/~keithp/porterduff/p253-porter.pdf
* @param {String} strColor1 color over
* @param {String} strColor2 color under
* @return {String} the composite color
*/
mergePixels : function (strColor1, strColor2, globalOpacity1) {
var col1 = pskl.utils.FrameUtils.toRgba(strColor1);
var col2 = pskl.utils.FrameUtils.toRgba(strColor2);
if (typeof globalOpacity1 == 'number') {
col1 = JSON.parse(JSON.stringify(col1));
col1.a = globalOpacity1 * col1.a;
}
var a = col1.a + col2.a * (1 - col1.a);
var r = ((col1.r * col1.a + col2.r * col2.a * (1 - col1.a)) / a)|0;
var g = ((col1.g * col1.a + col2.g * col2.a * (1 - col1.a)) / a)|0;
var b = ((col1.b * col1.a + col2.b * col2.a * (1 - col1.a)) / a)|0;
return 'rgba('+r+','+g+','+b+','+a+')';
},
/**
* Convert a color defined as a string (hex, rgba, rgb, 'TRANSPARENT') to an Object with r,g,b,a properties.
* r, g and b are integers between 0 and 255, a is a float between 0 and 1
* @param {String} c color as a string
* @return {Object} {r:Number,g:Number,b:Number,a:Number}
*/
toRgba : function (c) {
if (colorCache[c]) {
return colorCache[c];
}
var color, matches;
if (c === 'TRANSPARENT') {
color = {
r : 0,
g : 0,
b : 0,
a : 0
};
} else if (c.indexOf('rgba(') != -1) {
matches = /rgba\((\d+)\s*,\s*(\d+)\s*,\s*(\d+)\s*,\s*(1|0\.\d+)\s*\)/.exec(c);
color = {
r : parseInt(matches[1],10),
g : parseInt(matches[2],10),
b : parseInt(matches[3],10),
a : parseFloat(matches[4])
};
} else if (c.indexOf('rgb(') != -1) {
matches = /rgb\((\d+)\s*,\s*(\d+)\s*,\s*(\d+)\s*\)/.exec(c);
color = {
r : parseInt(matches[1],10),
g : parseInt(matches[2],10),
b : parseInt(matches[3],10),
a : 1
};
} else {
matches = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(c);
color = {
r : parseInt(matches[1], 16),
g : parseInt(matches[2], 16),
b : parseInt(matches[3], 16),
a : 1
};
}
colorCache[c] = color;
return color;
}
};
})();