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Ingy döt Net 2013-10-27 22:24:23 +00:00
parent 6f050a029e
commit 776bba907c
3887 changed files with 59894 additions and 7280 deletions
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52
Task/Xiaolin-Wus-line-algorithm/D/xiaolin-wus-line-algorithm.d
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@ -1,27 +1,27 @@
import std.math, std.algorithm, grayscale_image;
/// Plots anti-aliased line by Xiaolin Wu's line algorithm.
void aaLine(Color)(ref Image!Color img, double x1, double y1,
double x2, double y2,
in Color color)
/*pure*/ nothrow {
void aaLine(Color)(ref Image!Color img,
double x1, double y1,
double x2, double y2,
in Color color) /*pure*/ nothrow {
// Straight translation of Wikipedia pseudocode.
static double round(in double x) /*pure*/ nothrow {
return floor(x + 0.5); // Not pure.
static double round(in double x) pure nothrow {
return floor(x + 0.5);
}
static double fpart(in double x) /*pure*/ nothrow {
return x - floor(x);
static double fpart(in double x) pure nothrow {
return x - x.floor;
}
static double rfpart(in double x) /*pure*/ nothrow {
static double rfpart(in double x) pure nothrow {
return 1 - fpart(x);
}
auto dx = x2 - x1;
auto dy = y2 - y1;
immutable ax = abs(dx);
immutable ay = abs(dy);
immutable ax = dx.abs;
immutable ay = dy.abs;
static Color mixColors(in Color c1, in Color c2, in double p)
pure nothrow {
@ -35,17 +35,21 @@ void aaLine(Color)(ref Image!Color img, double x1, double y1,
}
// Plot function set here to handle the two cases of slope.
void delegate(in int, in int, in double) nothrow plot;
void delegate(ref Image!Color img, in int, in int, in double)
pure nothrow plot;
if (ax < ay) {
swap(x1, y1);
swap(x2, y2);
swap(dx, dy);
plot = (x, y, p) {
//plot = (img, x, y, p) {
plot = (ref Image!Color img, x, y, p) {
assert(p >= 0.0 && p <= 1.0);
img[y, x] = mixColors(color, img[y, x], p);
};
} else {
plot = (x, y, p) {
//plot = (img, x, y, p) {
plot = (ref Image!Color img, x, y, p) {
assert(p >= 0.0 && p <= 1.0);
img[x, y] = mixColors(color, img[x, y], p);
};
@ -58,31 +62,31 @@ void aaLine(Color)(ref Image!Color img, double x1, double y1,
immutable gradient = dy / dx;
// Handle first endpoint.
auto xEnd = round(x1);
auto xEnd = x1.round; // Not pure.
auto yEnd = y1 + gradient * (xEnd - x1);
auto xGap = rfpart(x1 + 0.5);
// This will be used in the main loop.
immutable xpxl1 = cast(int)xEnd;
immutable ypxl1 = cast(int)floor(yEnd);
plot(xpxl1, ypxl1, rfpart(yEnd) * xGap);
plot(xpxl1, ypxl1 + 1, fpart(yEnd) * xGap);
immutable ypxl1 = cast(int)yEnd.floor;
plot(img, xpxl1, ypxl1, rfpart(yEnd) * xGap);
plot(img, xpxl1, ypxl1 + 1, fpart(yEnd) * xGap);
// First y-intersection for the main loop.
auto yInter = yEnd + gradient;
// Handle second endpoint.
xEnd = round(x2);
xEnd = x2.round;
yEnd = y2 + gradient * (xEnd - x2);
xGap = fpart(x2 + 0.5);
// This will be used in the main loop.
immutable xpxl2 = cast(int)xEnd;
immutable ypxl2 = cast(int)floor(yEnd);
plot(xpxl2, ypxl2, rfpart(yEnd) * xGap);
plot(xpxl2, ypxl2 + 1, fpart(yEnd) * xGap);
immutable ypxl2 = cast(int)yEnd.floor;
plot(img, xpxl2, ypxl2, rfpart(yEnd) * xGap);
plot(img, xpxl2, ypxl2 + 1, fpart(yEnd) * xGap);
// Main loop.
foreach (immutable x; xpxl1 + 1 .. xpxl2) {
plot(x, cast(int)floor(yInter), rfpart(yInter));
plot(x, cast(int)floor(yInter) + 1, fpart(yInter));
plot(img, x, cast(int)yInter.floor, rfpart(yInter));
plot(img, x, cast(int)yInter.floor + 1, fpart(yInter));
yInter += gradient;
}
}