Merge parallel horizontal edges in ImagingDrawPolygon

This commit is contained in:
Andrew Murray 2021-03-21 00:33:54 +11:00
parent fe668716ed
commit 5491bd5eda

View File

@ -734,7 +734,7 @@ ImagingDrawRectangle(
int
ImagingDrawPolygon(Imaging im, int count, int *xy, const void *ink_, int fill, int op) {
int i, n;
int i, n, x0, y0, x1, y1;
DRAW *draw;
INT32 ink;
@ -753,10 +753,28 @@ ImagingDrawPolygon(Imaging im, int count, int *xy, const void *ink_, int fill, i
return -1;
}
for (i = n = 0; i < count - 1; i++) {
add_edge(&e[n++], xy[i + i], xy[i + i + 1], xy[i + i + 2], xy[i + i + 3]);
x0 = xy[i * 2];
y0 = xy[i * 2 + 1];
x1 = xy[i * 2 + 2];
y1 = xy[i * 2 + 3];
if (y0 == y1 && i != 0 && y0 == xy[i * 2 - 1]) {
// This is a horizontal line,
// that immediately follows another horizontal line
Edge *last_e = &e[n-1];
if (x1 > x0 && x0 > xy[i * 2 - 2]) {
// They are both increasing in x
last_e->xmax = x1;
continue;
} else if (x1 < x0 && x0 < xy[i * 2 - 2]) {
// They are both decreasing in x
last_e->xmin = x1;
continue;
}
}
add_edge(&e[n++], x0, y0, x1, y1);
}
if (xy[i + i] != xy[0] || xy[i + i + 1] != xy[1]) {
add_edge(&e[n++], xy[i + i], xy[i + i + 1], xy[0], xy[1]);
if (xy[i * 2] != xy[0] || xy[i * 2 + 1] != xy[1]) {
add_edge(&e[n++], xy[i * 2], xy[i * 2 + 1], xy[0], xy[1]);
}
draw->polygon(im, n, e, ink, 0);
free(e);
@ -764,9 +782,9 @@ ImagingDrawPolygon(Imaging im, int count, int *xy, const void *ink_, int fill, i
} else {
/* Outline */
for (i = 0; i < count - 1; i++) {
draw->line(im, xy[i + i], xy[i + i + 1], xy[i + i + 2], xy[i + i + 3], ink);
draw->line(im, xy[i * 2], xy[i * 2 + 1], xy[i * 2 + 2], xy[i * 2 + 3], ink);
}
draw->line(im, xy[i + i], xy[i + i + 1], xy[0], xy[1], ink);
draw->line(im, xy[i * 2], xy[i * 2 + 1], xy[0], xy[1], ink);
}
return 0;