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Bitmap/Midpoint circle algorithm: Difference between revisions
Bitmap/Midpoint circle algorithm (view source)
Revision as of 08:49, 20 December 2012
, 11 years agoMathematica
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</lang>
=={{header|Mathematica}}==
<lang mathematica>SetAttributes[drawcircle, HoldFirst];
drawcircle[img_, {x0_, y0_}, r_, color_: White] :=
Module[{f = 1 - r, ddfx = 1, ddfy = -2 r, x = 0, y = r,
pixels = {{0, r}, {0, -r}, {r, 0}, {-r, 0}}},
While[x < y,
If[f >= 0, y--; ddfy += 2; f += ddfy];
x++; ddfx += 2; f += ddfx;
pixels = Join[pixels, {{x, y}, {x, -y}, {-x, y}, {-x, -y},
{y, x}, {y, -x}, {-y, x}, {-y, -x}}]];
img = ReplacePixelValue[img, {x0, y0} + # -> color & /@ pixels]]</lang>
Example usage:
<lang mathematica>img = ExampleData[{"TestImage", "Lena"}];
drawcircle[img, {250, 250}, 100]</lang>
=={{header|Modula-3}}==
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