From 1569f75fd168b6f76a3c3899d9f7d969f636bad3 Mon Sep 17 00:00:00 2001
From: Michael Fogleman <fogleman@gmail.com>
Date: Thu, 3 Oct 2019 20:07:12 -0400
Subject: [PATCH] circles offset

---
 examples/circles_offset.py | 56 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)
 create mode 100644 examples/circles_offset.py

diff --git a/examples/circles_offset.py b/examples/circles_offset.py
new file mode 100644
index 0000000..27aa184
--- /dev/null
+++ b/examples/circles_offset.py
@@ -0,0 +1,56 @@
+import axi
+import math
+import random
+
+W, H = axi.A3_SIZE
+
+def circle_ray_intersection(cx, cy, cr, ox, oy, dx, dy):
+    xd = ox - cx
+    yd = oy - cy
+    a = dx * dx + dy * dy
+    b = 2 * (dx * (ox - cx) + dy * (oy - cy))
+    c = xd * xd + yd * yd - cr * cr
+    d = b * b - 4 * a * c
+    if d < 0:
+        return None
+    t = (-b + math.sqrt(d)) / (2 * a)
+    x = ox + dx * t
+    y = oy + dy * t
+    return (x, y)
+
+def path(x0, y0, r0, x1, y1, r1):
+    t = random.random()
+    a0 = random.random() * 2 * math.pi
+    a1 = a0 + math.radians(10)
+    n = 100
+    result = []
+    for i in range(n + 1):
+        u = i / n
+        a = a0 + (a1 - a0) * u
+        dx = math.cos(a)
+        dy = math.sin(a)
+        ax, ay = circle_ray_intersection(x0, y0, r0, x0, y0, dx, dy)
+        bx, by = circle_ray_intersection(x1, y1, r1, x0, y0, dx, dy)
+        x = ax + (bx - ax) * t
+        y = ay + (by - ay) * t
+        result.append((x, y))
+    return result
+
+def main():
+    x0 = 0
+    y0 = 0
+    r0 = 1.5
+    x1 = -0.25
+    y1 = 0
+    r1 = 2
+    paths = []
+    for i in range(500):
+        paths.append(path(x0, y0, r0, x1, y1, r1))
+    d = axi.Drawing(paths).rotate_and_scale_to_fit(W, H)#.sort_paths()
+    im = d.render()
+    im.write_to_png('circles_offset.png')
+    d.dump('circles_offset.axi')
+    # axi.draw(d)
+
+if __name__ == '__main__':
+    main()