27 lines
672 B
JavaScript
27 lines
672 B
JavaScript
var degrees = 180 / Math.PI;
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export var identity = {
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translateX: 0,
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translateY: 0,
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rotate: 0,
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skewX: 0,
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scaleX: 1,
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scaleY: 1
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};
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export default function(a, b, c, d, e, f) {
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var scaleX, scaleY, skewX;
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if (scaleX = Math.sqrt(a * a + b * b)) a /= scaleX, b /= scaleX;
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if (skewX = a * c + b * d) c -= a * skewX, d -= b * skewX;
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if (scaleY = Math.sqrt(c * c + d * d)) c /= scaleY, d /= scaleY, skewX /= scaleY;
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if (a * d < b * c) a = -a, b = -b, skewX = -skewX, scaleX = -scaleX;
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return {
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translateX: e,
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translateY: f,
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rotate: Math.atan2(b, a) * degrees,
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skewX: Math.atan(skewX) * degrees,
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scaleX: scaleX,
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scaleY: scaleY
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};
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}
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