17 lines
372 B
JavaScript
17 lines
372 B
JavaScript
'use strict';
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module.exports = function paethPredictor(left, above, upLeft) {
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var paeth = left + above - upLeft;
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var pLeft = Math.abs(paeth - left);
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var pAbove = Math.abs(paeth - above);
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var pUpLeft = Math.abs(paeth - upLeft);
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if (pLeft <= pAbove && pLeft <= pUpLeft) {
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return left;
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}
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if (pAbove <= pUpLeft) {
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return above;
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}
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return upLeft;
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}; |