refactor(es modules): continue migration

modules/relief-icons.js

@@ -1,4 +1,4 @@
-"use strict";
+import {getPackPolygon} from "/src/utils/graphUtils";
 
 window.ReliefIcons = (function () {
   const ReliefIcons = function () {
@@ -124,5 +124,67 @@ window.ReliefIcons = (function () {
     return "#relief-" + getOldIcon(type) + "-1"; // simple
   }
 
+  // mbostock's poissonDiscSampler
+  function* poissonDiscSampler(x0, y0, x1, y1, r, k = 3) {
+    if (!(x1 >= x0) || !(y1 >= y0) || !(r > 0)) throw new Error();
+
+    const width = x1 - x0;
+    const height = y1 - y0;
+    const r2 = r * r;
+    const r2_3 = 3 * r2;
+    const cellSize = r * Math.SQRT1_2;
+    const gridWidth = Math.ceil(width / cellSize);
+    const gridHeight = Math.ceil(height / cellSize);
+    const grid = new Array(gridWidth * gridHeight);
+    const queue = [];
+
+    function far(x, y) {
+      const i = (x / cellSize) | 0;
+      const j = (y / cellSize) | 0;
+      const i0 = Math.max(i - 2, 0);
+      const j0 = Math.max(j - 2, 0);
+      const i1 = Math.min(i + 3, gridWidth);
+      const j1 = Math.min(j + 3, gridHeight);
+      for (let j = j0; j < j1; ++j) {
+        const o = j * gridWidth;
+        for (let i = i0; i < i1; ++i) {
+          const s = grid[o + i];
+          if (s) {
+            const dx = s[0] - x;
+            const dy = s[1] - y;
+            if (dx * dx + dy * dy < r2) return false;
+          }
+        }
+      }
+      return true;
+    }
+
+    function sample(x, y) {
+      queue.push((grid[gridWidth * ((y / cellSize) | 0) + ((x / cellSize) | 0)] = [x, y]));
+      return [x + x0, y + y0];
+    }
+
+    yield sample(width / 2, height / 2);
+
+    pick: while (queue.length) {
+      const i = (Math.random() * queue.length) | 0;
+      const parent = queue[i];
+
+      for (let j = 0; j < k; ++j) {
+        const a = 2 * Math.PI * Math.random();
+        const r = Math.sqrt(Math.random() * r2_3 + r2);
+        const x = parent[0] + r * Math.cos(a);
+        const y = parent[1] + r * Math.sin(a);
+        if (0 <= x && x < width && 0 <= y && y < height && far(x, y)) {
+          yield sample(x, y);
+          continue pick;
+        }
+      }
+
+      const r = queue.pop();
+      if (i < queue.length) queue[i] = r;
+    }
+  }
+
   return ReliefIcons;
 })();