B

Task/Bitmap-Bresenhams-line-algorithm/Python/bitmap-bresenhams-line-algorithm.py

@@ -0,0 +1,58 @@
+def line(self, x0, y0, x1, y1):
+    "Bresenham's line algorithm"
+    dx = abs(x1 - x0)
+    dy = abs(y1 - y0)
+    x, y = x0, y0
+    sx = -1 if x0 > x1 else 1
+    sy = -1 if y0 > y1 else 1
+    if dx > dy:
+        err = dx / 2.0
+        while x != x1:
+            self.set(x, y)
+            err -= dy
+            if err < 0:
+                y += sy
+                err += dx
+            x += sx
+    else:
+        err = dy / 2.0
+        while y != y1:
+            self.set(x, y)
+            err -= dx
+            if err < 0:
+                x += sx
+                err += dy
+            y += sy
+    self.set(x, y)
+Bitmap.line = line
+
+bitmap = Bitmap(17,17)
+for points in ((1,8,8,16),(8,16,16,8),(16,8,8,1),(8,1,1,8)):
+    bitmap.line(*points)
+bitmap.chardisplay()
+
+'''
+The origin, 0,0; is the lower left, with x increasing to the right,
+and Y increasing upwards.
+
+The chardisplay above produces the following output :
++-----------------+
+|        @        |
+|       @ @       |
+|      @   @      |
+|     @     @     |
+|    @       @    |
+|    @        @   |
+|   @          @  |
+|  @            @ |
+| @              @|
+|  @            @ |
+|   @          @  |
+|    @       @@   |
+|     @     @     |
+|      @   @      |
+|       @ @       |
+|        @        |
+|                 |
++-----------------+
+'''