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Xiaolin Wu's line algorithm: Difference between revisions
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Line 281:
#undef fpart_
#undef round_
#undef rfpart_
</lang>
== {{header|C++}} ==
<lang c++>
#include <functional>
#include <algorithm>
#include <utility>
void WuDrawLine(float x0, float y0, float x1, float y1,
const std::function<void(int x, int y, float brightess)>& plot) {
auto ipart = [](float x) -> int {return int(std::floor(x));};
auto round = [](float x) -> float {return std::round(x);};
auto fpart = [](float x) -> float {return x - std::floor(x);};
auto rfpart = [=](float x) -> float {return 1 - fpart(x);};
const bool steep = abs(y1 - y0) > abs(x1 - x0);
if (steep) {
std::swap(x0,y0);
std::swap(x1,y1);
}
if (x0 > x1) {
std::swap(x0,x1);
std::swap(y0,y1);
}
const float dx = x1 - x0;
const float dy = y1 - y0;
const float gradient = (dx == 0) ? 1 : dy/dx;
int xpx11;
float intery;
{
const float xend = round(x0);
const float yend = y0 + gradient * (xend - x0);
const float xgap = rfpart(x0 + 0.5);
xpx11 = int(xend);
const int ypx11 = ipart(yend);
if (steep) {
plot(ypx11, xpx11, rfpart(yend) * xgap);
plot(ypx11 + 1, xpx11, fpart(yend) * xgap);
} else {
plot(xpx11, ypx11, rfpart(yend) * xgap);
plot(xpx11, ypx11 + 1, fpart(yend) * xgap);
}
intery = yend + gradient;
}
int xpx12;
{
const float xend = round(x1);
const float yend = y1 + gradient * (xend - x1);
const float xgap = rfpart(x1 + 0.5);
xpx12 = int(xend);
const int ypx12 = ipart(yend);
if (steep) {
plot(ypx12, xpx12, rfpart(yend) * xgap);
plot(ypx12 + 1, xpx12, fpart(yend) * xgap);
} else {
plot(xpx12, ypx12, rfpart(yend) * xgap);
plot(xpx12, ypx12 + 1, fpart(yend) * xgap);
}
}
if (steep) {
for (int x = xpx11 + 1; x < xpx12; x++) {
plot(ipart(intery), x, rfpart(intery));
plot(ipart(intery) + 1, x, fpart(intery));
intery += gradient;
}
} else {
for (int x = xpx11 + 1; x < xpx12; x++) {
plot(x, ipart(intery), rfpart(intery));
plot(x, ipart(intery) + 1, fpart(intery));
intery += gradient;
}
}
}
</lang>
== {{header|C#}} ==
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