Anonymous user
Bitmap/Midpoint circle algorithm: Difference between revisions
→{{header|Modula-3}}
m (→{{header|Lua}}: corrected axes) |
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PPM.Create("testpic.ppm", testpic);
END Main.</lang>
=={{header|Nim}}==
{{trans|Ada}}
<lang Nim>import bitmap
proc setPixel(img: var Image; x, y: int; color: Color) {.inline.} =
# Set a pixel at a given color.
# Ignore if the point is outside of the image.
if x in 0..<img.w and y in 0..<img.h:
img[x, y] = color
proc drawCircle(img: var Image; center: Point; radius: Natural; color: Color) =
## Draw a circle using midpoint circle algorithm.
var
f = 1 - radius
ddFX = 0
ddFY = -2 * radius
x = 0
y = radius
img.setPixel(center.x, center.y + radius, color)
img.setPixel(center.x, center.y - radius, color)
img.setPixel(center.x + radius, center.y, color)
img.setPixel(center.x - radius, center.y, color)
while x < y:
if f >= 0:
dec y
inc ddFY, 2
inc f, ddFY
inc x
inc ddFX, 2
inc f, ddFX + 1
img.setPixel(center.x + x, center.y + y, color)
img.setPixel(center.x - x, center.y + y, color)
img.setPixel(center.x + x, center.y - y, color)
img.setPixel(center.x - x, center.y - y, color)
img.setPixel(center.x + y, center.y + x, color)
img.setPixel(center.x - y, center.y + x, color)
img.setPixel(center.x + y, center.y - x, color)
img.setPixel(center.x - y, center.y - x, color)
#———————————————————————————————————————————————————————————————————————————————————————————————————
when isMainModule:
var img = initImage(16, 16)
img.fill(White)
img.drawCircle((7, 7), 5, Black)
img.print()</lang>
{{out}}
<pre>................
................
.....HHHHH......
....H.....H.....
...H.......H....
..H.........H...
..H.........H...
..H.........H...
..H.........H...
..H.........H...
...H.......H....
....H.....H.....
.....HHHHH......
................
................
................</pre>
=={{header|Phix}}==
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