Re-structuring package layout

toolboxes/STLtoVoxel/perimeter.py

@@ -0,0 +1,68 @@
+from functools import reduce
+
+
+def lines_to_voxels(line_list, pixels):
+    current_line_indices = set()
+    x = 0
+    for (event_x, status, line_ind) in generate_line_events(line_list):
+        while event_x - x >= 0:
+            lines = reduce(lambda acc, cur: acc + [line_list[cur]], current_line_indices, [])
+            paint_y_axis(lines, pixels, x)
+            x += 1
+
+        if status == 'start':
+            assert line_ind not in current_line_indices
+            current_line_indices.add(line_ind)
+        elif status == 'end':
+            assert line_ind in current_line_indices
+            current_line_indices.remove(line_ind)
+
+
+def slope_intercept(p1, p2):
+    x1, y1 = p1[:2]
+    x2, y2 = p2[:2]
+    slope = (y2 - y1) / (x2 - x1)
+    intercept = y1 - slope * x1
+    
+    return slope, intercept
+
+
+def generate_y(p1, p2, x):
+    slope, intercept = slope_intercept(p1, p2)
+    y = slope * x + intercept
+    
+    return y
+
+
+def paint_y_axis(lines, pixels, x):
+    is_black = False
+    target_ys = list(map(lambda line: int(generate_y(line[0], line[1], x)), lines))
+    target_ys.sort()
+    if len(target_ys) % 2:
+        distances = []
+        for i in range(len(target_ys) - 1):
+            distances.append(target_ys[i+1] - target_ys[i])
+        # https://stackoverflow.com/a/17952763
+        min_idx = -min((x, -i) for i, x in enumerate(distances))[1]
+        del target_ys[min_idx]
+
+    yi = 0
+    for target_y in target_ys:
+        if is_black:
+            # Bulk assign all pixels between yi -> target_y
+            pixels[yi:target_y, x] = True
+        pixels[target_y][x] = True
+        is_black = not is_black
+        yi = target_y
+    assert is_black is False, 'an error has occured at x%s' % x
+
+
+def generate_line_events(line_list):
+    events = []
+    
+    for i, line in enumerate(line_list):
+        first, second = sorted(line, key=lambda pt: pt[0])
+        events.append((first[0], 'start', i))
+        events.append((second[0], 'end', i))
+    
+    return sorted(events, key=lambda tup: tup[0])