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37 lines
1.7 KiB
JavaScript
37 lines
1.7 KiB
JavaScript
4 years ago
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import { lineLength } from '../geometry';
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import { polygonHachureLines } from './scan-line-hachure';
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export class DashedFiller {
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constructor(helper) {
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this.helper = helper;
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}
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fillPolygon(points, o) {
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const lines = polygonHachureLines(points, o);
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return { type: 'fillSketch', ops: this.dashedLine(lines, o) };
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}
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dashedLine(lines, o) {
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const offset = o.dashOffset < 0 ? (o.hachureGap < 0 ? (o.strokeWidth * 4) : o.hachureGap) : o.dashOffset;
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const gap = o.dashGap < 0 ? (o.hachureGap < 0 ? (o.strokeWidth * 4) : o.hachureGap) : o.dashGap;
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const ops = [];
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lines.forEach((line) => {
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const length = lineLength(line);
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const count = Math.floor(length / (offset + gap));
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const startOffset = (length + gap - (count * (offset + gap))) / 2;
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let p1 = line[0];
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let p2 = line[1];
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if (p1[0] > p2[0]) {
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p1 = line[1];
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p2 = line[0];
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}
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const alpha = Math.atan((p2[1] - p1[1]) / (p2[0] - p1[0]));
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for (let i = 0; i < count; i++) {
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const lstart = i * (offset + gap);
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const lend = lstart + offset;
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const start = [p1[0] + (lstart * Math.cos(alpha)) + (startOffset * Math.cos(alpha)), p1[1] + lstart * Math.sin(alpha) + (startOffset * Math.sin(alpha))];
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const end = [p1[0] + (lend * Math.cos(alpha)) + (startOffset * Math.cos(alpha)), p1[1] + (lend * Math.sin(alpha)) + (startOffset * Math.sin(alpha))];
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ops.push(...this.helper.doubleLineOps(start[0], start[1], end[0], end[1], o));
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}
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});
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return ops;
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}
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}
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