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54 lines
1.7 KiB
54 lines
1.7 KiB
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// Adds any extra JS functions/helpers we want to add to CanvasKit.
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// Wrapped in a function to avoid leaking global variables.
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(function(CanvasKit){
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function clamp(c) {
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return Math.round(Math.max(0, Math.min(c || 0, 255)));
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}
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// Colors are just a 32 bit number with 8 bits each of a, r, g, b
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// The API is the same as CSS's representation of color rgba(), that is
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// r,g,b are 0-255, and a is 0.0 to 1.0.
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// if a is omitted, it will be assumed to be 1.0
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CanvasKit.Color = function(r, g, b, a) {
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if (a === undefined) {
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a = 1;
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}
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return (clamp(a*255) << 24) | (clamp(r) << 16) | (clamp(g) << 8) | (clamp(b) << 0);
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}
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// returns [r, g, b, a] from a color
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// where a is scaled between 0 and 1.0
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CanvasKit.getColorComponents = function(color) {
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return [
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(color >> 16) & 0xFF,
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(color >> 8) & 0xFF,
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(color >> 0) & 0xFF,
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((color >> 24) & 0xFF) / 255,
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]
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}
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CanvasKit.multiplyByAlpha = function(color, alpha) {
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if (alpha === 1) {
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return color;
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}
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// extract as int from 0 to 255
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var a = (color >> 24) & 0xFF;
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a *= alpha;
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// mask off the old alpha
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color &= 0xFFFFFF;
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return clamp(a) << 24 | color;
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}
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}(Module)); // When this file is loaded in, the high level object is "Module";
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// See https://stackoverflow.com/a/31090240
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// This contraption keeps closure from minifying away the check
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// if btoa is defined *and* prevents runtime "btoa" or "window" is not defined.
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// Defined outside any scopes to make it available in all files.
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var isNode = !(new Function("try {return this===window;}catch(e){ return false;}")());
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function almostEqual(floata, floatb) {
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return Math.abs(floata - floatb) < 0.00001;
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} |