First commit.

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

client/node_modules/hachure-fill/bin/hachure.js

@@ -0,0 +1,146 @@
+function rotatePoints(points, center, degrees) {
+    if (points && points.length) {
+        const [cx, cy] = center;
+        const angle = (Math.PI / 180) * degrees;
+        const cos = Math.cos(angle);
+        const sin = Math.sin(angle);
+        for (const p of points) {
+            const [x, y] = p;
+            p[0] = ((x - cx) * cos) - ((y - cy) * sin) + cx;
+            p[1] = ((x - cx) * sin) + ((y - cy) * cos) + cy;
+        }
+    }
+}
+function rotateLines(lines, center, degrees) {
+    const points = [];
+    lines.forEach((line) => points.push(...line));
+    rotatePoints(points, center, degrees);
+}
+function areSamePoints(p1, p2) {
+    return p1[0] === p2[0] && p1[1] === p2[1];
+}
+export function hachureLines(polygons, hachureGap, hachureAngle, hachureStepOffset = 1) {
+    const angle = hachureAngle;
+    const gap = Math.max(hachureGap, 0.1);
+    const polygonList = (polygons[0] && polygons[0][0] && (typeof polygons[0][0] === 'number')) ? [polygons] : polygons;
+    const rotationCenter = [0, 0];
+    if (angle) {
+        for (const polygon of polygonList) {
+            rotatePoints(polygon, rotationCenter, angle);
+        }
+    }
+    const lines = straightHachureLines(polygonList, gap, hachureStepOffset);
+    if (angle) {
+        for (const polygon of polygonList) {
+            rotatePoints(polygon, rotationCenter, -angle);
+        }
+        rotateLines(lines, rotationCenter, -angle);
+    }
+    return lines;
+}
+function straightHachureLines(polygons, gap, hachureStepOffset) {
+    const vertexArray = [];
+    for (const polygon of polygons) {
+        const vertices = [...polygon];
+        if (!areSamePoints(vertices[0], vertices[vertices.length - 1])) {
+            vertices.push([vertices[0][0], vertices[0][1]]);
+        }
+        if (vertices.length > 2) {
+            vertexArray.push(vertices);
+        }
+    }
+    const lines = [];
+    gap = Math.max(gap, 0.1);
+    // Create sorted edges table
+    const edges = [];
+    for (const vertices of vertexArray) {
+        for (let i = 0; i < vertices.length - 1; i++) {
+            const p1 = vertices[i];
+            const p2 = vertices[i + 1];
+            if (p1[1] !== p2[1]) {
+                const ymin = Math.min(p1[1], p2[1]);
+                edges.push({
+                    ymin,
+                    ymax: Math.max(p1[1], p2[1]),
+                    x: ymin === p1[1] ? p1[0] : p2[0],
+                    islope: (p2[0] - p1[0]) / (p2[1] - p1[1]),
+                });
+            }
+        }
+    }
+    edges.sort((e1, e2) => {
+        if (e1.ymin < e2.ymin) {
+            return -1;
+        }
+        if (e1.ymin > e2.ymin) {
+            return 1;
+        }
+        if (e1.x < e2.x) {
+            return -1;
+        }
+        if (e1.x > e2.x) {
+            return 1;
+        }
+        if (e1.ymax === e2.ymax) {
+            return 0;
+        }
+        return (e1.ymax - e2.ymax) / Math.abs((e1.ymax - e2.ymax));
+    });
+    if (!edges.length) {
+        return lines;
+    }
+    // Start scanning
+    let activeEdges = [];
+    let y = edges[0].ymin;
+    let iteration = 0;
+    while (activeEdges.length || edges.length) {
+        if (edges.length) {
+            let ix = -1;
+            for (let i = 0; i < edges.length; i++) {
+                if (edges[i].ymin > y) {
+                    break;
+                }
+                ix = i;
+            }
+            const removed = edges.splice(0, ix + 1);
+            removed.forEach((edge) => {
+                activeEdges.push({ s: y, edge });
+            });
+        }
+        activeEdges = activeEdges.filter((ae) => {
+            if (ae.edge.ymax <= y) {
+                return false;
+            }
+            return true;
+        });
+        activeEdges.sort((ae1, ae2) => {
+            if (ae1.edge.x === ae2.edge.x) {
+                return 0;
+            }
+            return (ae1.edge.x - ae2.edge.x) / Math.abs((ae1.edge.x - ae2.edge.x));
+        });
+        // fill between the edges
+        if ((hachureStepOffset !== 1) || (iteration % gap === 0)) {
+            if (activeEdges.length > 1) {
+                for (let i = 0; i < activeEdges.length; i = i + 2) {
+                    const nexti = i + 1;
+                    if (nexti >= activeEdges.length) {
+                        break;
+                    }
+                    const ce = activeEdges[i].edge;
+                    const ne = activeEdges[nexti].edge;
+                    lines.push([
+                        [Math.round(ce.x), y],
+                        [Math.round(ne.x), y],
+                    ]);
+                }
+            }
+        }
+        y += hachureStepOffset;
+        activeEdges.forEach((ae) => {
+            ae.edge.x = ae.edge.x + (hachureStepOffset * ae.edge.islope);
+        });
+        iteration++;
+    }
+    return lines;
+}