67 lines
1.8 KiB
JavaScript
67 lines
1.8 KiB
JavaScript
/**
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* @file reduceGlyf.js
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* @author mengke01
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* @date
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* @description
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* 缩减glyf大小，去除冗余节点
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*/
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define(
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function(require) {
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/**
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* 判断点是否多余的点
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*
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* @param {Object} p 当前
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* @param {Object} prev 上一个
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* @param {Object} next 下一个
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* @return {boolean}
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*/
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function redundant(p, prev, next) {
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// 是否重合的点, 只有两个点同在曲线上或者同不在曲线上移出
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if ( Math.pow(p.x - next.x, 2) + Math.pow(p.y - next.y, 2) <= 1) {
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return !p.onCurve ^ !!next.onCurve;
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}
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// 三点同线
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// else if ((next.y - p.y) * (prev.x - p.x) == (prev.y - p.y) * (next.x - p.x)) {
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// return p.onCurve && prev.onCurve && next.onCurve;
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// }
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return false;
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}
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/**
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* 缩减glyf，去除冗余节点
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*
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* @param {Object} glyf glyf对象
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* @return {Object} glyf对象
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*/
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function reduceGlyf(glyf) {
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var contours = glyf.contours, contour, prev;
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for(var j = 0, cl = contours.length; j < cl; j++) {
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contour = contours[j];
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for(var i = contour.length - 1, last = i; i >= 0; i--) {
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// 这里注意逆序
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next = i === last ? contour[0] : contour[i + 1];
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prev = i === 0 ? contour[last] : contour[i - 1];
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p = contour[i];
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if (redundant(p, prev, next)) {
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contour.splice(i, 1);
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last--;
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continue;
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}
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}
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}
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}
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return reduceGlyf;
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}
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);
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