aparler/RosettaCodeData
1
0
Fork 0
Code Issues 12 Pull requests 3 Projects Releases Packages Wiki Activity Actions

Initial data commit

Browse source
This commit is contained in:
Ingy döt Net 2023-07-01 11:58:00 -04:00
parent 72d218235f
commit f23f22d71c
199087 changed files with 3378941 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

50
Task/Xiaolin-Wus-line-algorithm/Mathematica/xiaolin-wus-line-algorithm.math Normal file
View file

@ -0,0 +1,50 @@
ClearAll[ReverseFractionalPart, ReplacePixelWithAlpha, DrawEndPoint, DrawLine]
ReverseFractionalPart[x_] := 1 - FractionalPart[x]
ReplacePixelWithAlpha[img_Image, pos_ -> colvals : {_, _, _},
alpha_] := Module[{vals,},
vals = PixelValue[img, pos];
vals = (1 - alpha) vals + alpha colvals;
ReplacePixelValue[img, pos -> vals]
]
DrawEndPoint[img_Image, pt : {x_, y_}, grad_, p_] :=
Module[{xend, yend, xgap, px, py, i},
xend = Round[x];
yend = y + grad (xend - x);
xgap = ReverseFractionalPart[x + 0.5];
{px, py} = Floor[{xend, yend}];
i = ReplacePixelWithAlpha[img, p[{x, py}] -> {1, 1, 1}, ReverseFractionalPart[yend] xgap];
i = ReplacePixelWithAlpha[i, p[{x, py + 1}] -> {1, 1, 1}, FractionalPart[yend] xgap];
{px, i}
]
DrawLine[img_Image, p1 : {_, _}, p2 : {_, _}] :=
Module[{x1, x2, y1, y2, steep, p, grad, intery, xend, yend, x, y,
xstart, ystart, dx, dy, i},
{x1, y1} = p1;
{x2, y2} = p2;
dx = x2 - x1;
dy = y2 - y1;
steep = Abs[dx] < Abs[dy];
p = If[steep, Reverse[#], #] &;
If[steep,
{x1, y1, x2, y2, dx, dy} = {y1, x1, y2, x2, dy, dx}
];
If[x2 < x1,
{x1, x2, y1, y2} = {x2, x1, y2, y1}
];
grad = dy/dx;
intery = y1 + ReverseFractionalPart[x1] grad;
{xstart, i} = DrawEndPoint[img, p[p1], grad, p];
xstart += 1;
{xend, i} = DrawEndPoint[i, p[p2], grad, p];
Do[
y = Floor[intery];
i = ReplacePixelWithAlpha[i, p[{x, y}] -> {1, 1, 1}, ReverseFractionalPart[intery]];
i = ReplacePixelWithAlpha[i, p[{x, y + 1}] -> {1, 1, 1}, FractionalPart[intery]];
intery += grad
,
{x, xstart, xend}
];
i
]
image = ConstantImage[Black, {100, 100}];
Fold[DrawLine[#1, {20, 10}, #2] &, image, AngleVector[{20, 10}, {75, #}] & /@ Subdivide[0, Pi/2, 10]]