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1.7 KiB
JavaScript

import { lineLength } from '../geometry';
import { polygonHachureLines } from './scan-line-hachure';
export class ZigZagLineFiller {
constructor(helper) {
this.helper = helper;
}
fillPolygon(points, o) {
const gap = o.hachureGap < 0 ? (o.strokeWidth * 4) : o.hachureGap;
const zo = o.zigzagOffset < 0 ? gap : o.zigzagOffset;
o = Object.assign({}, o, { hachureGap: gap + zo });
const lines = polygonHachureLines(points, o);
return { type: 'fillSketch', ops: this.zigzagLines(lines, zo, o) };
}
zigzagLines(lines, zo, o) {
const ops = [];
lines.forEach((line) => {
const length = lineLength(line);
const count = Math.round(length / (2 * zo));
let p1 = line[0];
let p2 = line[1];
if (p1[0] > p2[0]) {
p1 = line[1];
p2 = line[0];
}
const alpha = Math.atan((p2[1] - p1[1]) / (p2[0] - p1[0]));
for (let i = 0; i < count; i++) {
const lstart = i * 2 * zo;
const lend = (i + 1) * 2 * zo;
const dz = Math.sqrt(2 * Math.pow(zo, 2));
const start = [p1[0] + (lstart * Math.cos(alpha)), p1[1] + lstart * Math.sin(alpha)];
const end = [p1[0] + (lend * Math.cos(alpha)), p1[1] + (lend * Math.sin(alpha))];
const middle = [start[0] + dz * Math.cos(alpha + Math.PI / 4), start[1] + dz * Math.sin(alpha + Math.PI / 4)];
ops.push(...this.helper.doubleLineOps(start[0], start[1], middle[0], middle[1], o), ...this.helper.doubleLineOps(middle[0], middle[1], end[0], end[1], o));
}
});
return ops;
}
}