tree rings example

examples/tree_rings.py

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+import axi
+import math
+import sys
+
+from PIL import Image
+
+def create_paths(im):
+    f = (255 * 255 * 3) ** 0.5
+    paths = []
+    w, h = im.size
+    for m in [-2, -1, 0, 1, 2]:
+        for radius in range(0, w, 8):
+            path = []
+            for a in range(1800):
+                a = math.radians(a / 10.0)
+                x = w / 2 + int(math.cos(a) * radius)
+                y = h - int(math.sin(a) * radius)
+                if x < 0 or x >= w:
+                    continue
+                if y < 0 or y >= h:
+                    continue
+                r, g, b = im.getpixel((x, y))
+                p = (r * r + g * g + b * b) ** 0.5
+                p = 1 - (p / f)
+                p = p ** 2
+                if p < 0.05:
+                    if len(path) > 1:
+                        paths.append(path)
+                    path = []
+                else:
+                    x = w / 2 + math.cos(a) * (radius + m * p * 1.5)
+                    y = h - math.sin(a) * (radius + m * p * 1.5)
+                    path.append((x, y))
+            if len(path) > 1:
+                paths.append(path)
+    return paths
+
+def main():
+    paths = create_paths(Image.open(sys.argv[1]))
+    drawing = axi.Drawing(paths).rotate_and_scale_to_fit(11, 8.5, step=90)
+    drawing = drawing.sort_paths().join_paths(0.02)
+    axi.draw(drawing)
+
+if __name__ == '__main__':
+    main()