get points on line; get line segments; color key hue shift

pgfw/extension.py

@@ -14,6 +14,24 @@ def get_step(start, end, speed):
 def get_step_relative(start, end, step):
     return get_step(start, end, get_distance(start, end) * step)
 
+def get_segments(start, end, count):
+    rel_step = get_step_relative(start, end, 1 / float(count))
+    segs = [[start]]
+    for ii in range(count):
+        seg_end = segs[-1][0][0] + rel_step[0], segs[-1][0][1] + rel_step[1]
+        segs[-1].append(seg_end)
+        if ii < count - 1:
+            segs.append([seg_end])
+    return segs
+
+def get_points_on_line(start, end, count):
+    rel_step = get_step_relative(start, end, 1 / float(count - 1))
+    points = [start]
+    for ii in range(count - 2):
+        points.append((points[-1][0] + rel_step[0], points[-1][1] + rel_step[1]))
+    points.append(end)
+    return points
+
 def get_angle(start, end, transpose=False):
     angle = atan2(end[1] - start[1], end[0] - start[0])
     if transpose:
@@ -170,8 +188,9 @@ def get_hue_shifted_surface(base, offset):
     color = Color(0, 0, 0)
     for x in range(surface.get_width()):
         for y in range(surface.get_height()):
-            h, s, l, a = Color(*surface.unmap_rgb(pixels[x][y])).hsla
-            if a:
+            rgb = surface.unmap_rgb(pixels[x][y])
+            h, s, l, a = Color(*rgb).hsla
+            if a and surface.get_colorkey() != rgb:
                 color.hsla = (int(h) + offset) % 360, int(s), int(l), int(a)
                 pixels[x][y] = color
     del pixels