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Bitmap/Bresenham's line algorithm: Difference between revisions
Bitmap/Bresenham's line algorithm (view source)
Revision as of 16:23, 7 November 2009
, 14 years ago→Python: Add Python example
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Line 780:
Images <tt>test0.png</tt> and <tt>test1.png</tt> look different since Imlib2 draw lines with antialiasing.
=={{header|Python}}==
{{works with|Python|3.1}}
Extending the example given [[Basic_bitmap_storage#Alternative_version|here]] and using the algorithm from the ADA solution:
<lang python>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 :
+-----------------+
| @ |
| @ @ |
| @ @ |
| @ @ |
| @ @ |
| @ @ |
| @ @ |
| @ @ |
| @ @|
| @ @ |
| @ @ |
| @ @@ |
| @ @ |
| @ @ |
| @ @ |
| @ |
| |
+-----------------+
'''</lang>
=={{header|RapidQ}}==
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