First commit.

Signed-off-by: Chen Xiao <abigwc@gmail.com>

client/node_modules/roughjs/bin/fillers/zigzag-filler.js

@@ -0,0 +1,31 @@
+import { HachureFiller } from './hachure-filler';
+import { polygonHachureLines } from './scan-line-hachure';
+import { lineLength } from '../geometry';
+export class ZigZagFiller extends HachureFiller {
+    fillPolygons(polygonList, o) {
+        let gap = o.hachureGap;
+        if (gap < 0) {
+            gap = o.strokeWidth * 4;
+        }
+        gap = Math.max(gap, 0.1);
+        const o2 = Object.assign({}, o, { hachureGap: gap });
+        const lines = polygonHachureLines(polygonList, o2);
+        const zigZagAngle = (Math.PI / 180) * o.hachureAngle;
+        const zigzagLines = [];
+        const dgx = gap * 0.5 * Math.cos(zigZagAngle);
+        const dgy = gap * 0.5 * Math.sin(zigZagAngle);
+        for (const [p1, p2] of lines) {
+            if (lineLength([p1, p2])) {
+                zigzagLines.push([
+                    [p1[0] - dgx, p1[1] + dgy],
+                    [...p2],
+                ], [
+                    [p1[0] + dgx, p1[1] - dgy],
+                    [...p2],
+                ]);
+            }
+        }
+        const ops = this.renderLines(zigzagLines, o);
+        return { type: 'fillSketch', ops };
+    }
+}