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Xiaolin Wu's line algorithm: Difference between revisions
Added Julia language
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}
}</lang>
=={{header|Julia}}==
{{works with|Julia|0.6}}
<lang julia>using Images
fpart(x) = mod(x, one(x))
rfpart(x) = one(x) - fpart(x)
function drawline!(img::Matrix{Gray{N0f8}}, x0::Integer, y0::Integer, x1::Integer, y1::Integer)
steep = abs(y1 - y0) > abs(x1 - x0)
if steep
x0, y0 = y0, x0
x1, y1 = y1, x1
end
if x0 > x1
x0, x1 = x1, x0
y0, y1 = y1, y0
end
dx = x1 - x0
dy = y1 - y0
grad = dy / dx
if iszero(dx)
grad = oftype(grad, 1.0)
end
# handle first endpoint
xend = round(Int, x0)
yend = y0 + grad * (xend - x0)
xgap = rfpart(x0 + 0.5)
xpxl1 = xend
ypxl1 = floor(Int, yend)
if steep
img[ypxl1, xpxl1] = rfpart(yend) * xgap
img[ypxl1+1, xpxl1] = fpart(yend) * xgap
else
img[xpxl1, ypxl1 ] = rfpart(yend) * xgap
img[xpxl1, ypxl1+1] = fpart(yend) * xgap
end
intery = yend + grad # first y-intersection for the main loop
# handle second endpoint
xend = round(Int, x1)
yend = y1 + grad * (xend - x1)
xgap = fpart(x1 + 0.5)
xpxl2 = xend
ypxl2 = floor(Int, yend)
if steep
img[ypxl2, xpxl2] = rfpart(yend) * xgap
img[ypxl2+1, xpxl2] = fpart(yend) * xgap
else
img[xpxl2, ypxl2 ] = rfpart(yend) * xgap
img[xpxl2, ypxl2+1] = fpart(yend) * xgap
end
# main loop
if steep
for x in xpxl1+1:xpxl2-1
img[floor(Int, intery), x] = rfpart(intery)
img[floor(Int, intery)+1, x] = fpart(intery)
intery += grad
end
else
for x in xpxl1+1:xpxl2-1
img[x, floor(Int, intery) ] = rfpart(intery)
img[x, floor(Int, intery)+1] = fpart(intery)
intery += grad
end
end
return img
end
img = fill(Gray(1.0N0f8), 250, 250);
drawline!(img, 8, 8, 192, 154)</lang>
=={{header|Kotlin}}==
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