feat(package): voronoi: simple voronoi algoritm realization

package/voronoi/voronoi.awk

@@ -0,0 +1,49 @@
+function clamp(v){ return v<0?0:(v>1?1:v) }
+function color_lerp(p, q, r1, g1, b1, r2, g2, b3, x){
+  t = (x - p) / (q - p)
+  t = clamp(t)
+  r = int(r1 + t*(r2 - r1) + 0.5)
+  g = int(g1 + t*(g2 - g1) + 0.5)
+  b = int(b1 + t*(b2 - b1) + 0.5)
+  return sprintf("#%02X%02X%02X", r, g, b)
+}
+BEGIN {
+  # external variables
+  # PTS  is voronoi centers
+  # W    is canvas width
+  # H    is canvas height
+  # FADE is fade max distance
+  # C1   is first color in gradient
+  # C2   is secont color in gradient
+
+  if (C1 == "") C1 = "0,0,0"
+  if (C2 == "") C2 = "255,255,255"
+  split(C1, c1, ",")
+  split(C2, c2, ",")
+
+  n = split(PTS, pairs, " ")
+  for (i = 1; i <= n; ++i) {
+    split(pairs[i], xy, ",")
+    px[i] = xy[1] + 0
+    py[i] = xy[2] + 0
+  }
+
+  for (y = 0; y < H; y++)
+    for (x = 0; x < W; x++) {
+      min_d = 1e308
+      for (i = 1; i <= n; i++) {
+        dx = x - px[i]
+        dy = y - py[i]
+        d = sqrt(dx*dx + dy*dy)
+        if (d < min_d)
+          min_d = d
+      }
+
+      fade = FADE - min_d
+      if (fade < 0) fade = 0
+
+      color = color_lerp(0, FADE, c1[1],c1[2],c1[3], c2[1],c2[2],c2[3], fade)
+
+      printf "fill %s point %d,%d\n", color, x, y
+    }
+}