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-rw-r--r--util/region.c49
1 files changed, 49 insertions, 0 deletions
diff --git a/util/region.c b/util/region.c
index 88e38fd2..38f84c5e 100644
--- a/util/region.c
+++ b/util/region.c
@@ -128,3 +128,52 @@ void wlr_region_expand(pixman_region32_t *dst, pixman_region32_t *src,
pixman_region32_init_rects(dst, dst_rects, nrects);
free(dst_rects);
}
+
+void wlr_region_rotated_bounds(pixman_region32_t *dst, pixman_region32_t *src,
+ float rotation, int ox, int oy) {
+ if (rotation == 0) {
+ pixman_region32_copy(dst, src);
+ return;
+ }
+
+ int nrects;
+ pixman_box32_t *src_rects = pixman_region32_rectangles(src, &nrects);
+
+ pixman_box32_t *dst_rects = malloc(nrects * sizeof(pixman_box32_t));
+ if (dst_rects == NULL) {
+ return;
+ }
+
+ for (int i = 0; i < nrects; ++i) {
+ double x1 = src_rects[i].x1 - ox;
+ double y1 = src_rects[i].y1 - oy;
+ double x2 = src_rects[i].x2 - ox;
+ double y2 = src_rects[i].y2 - oy;
+
+ double rx1 = x1 * cos(rotation) - y1 * sin(rotation);
+ double ry1 = x1 * sin(rotation) + y1 * cos(rotation);
+
+ double rx2 = x2 * cos(rotation) - y1 * sin(rotation);
+ double ry2 = x2 * sin(rotation) + y1 * cos(rotation);
+
+ double rx3 = x2 * cos(rotation) - y2 * sin(rotation);
+ double ry3 = x2 * sin(rotation) + y2 * cos(rotation);
+
+ double rx4 = x1 * cos(rotation) - y2 * sin(rotation);
+ double ry4 = x1 * sin(rotation) + y2 * cos(rotation);
+
+ x1 = fmin(fmin(rx1, rx2), fmin(rx3, rx4));
+ y1 = fmin(fmin(ry1, ry2), fmin(ry3, ry4));
+ x2 = fmax(fmax(rx1, rx2), fmax(rx3, rx4));
+ y2 = fmax(fmax(ry1, ry2), fmax(ry3, ry4));
+
+ dst_rects[i].x1 = floor(ox + x1);
+ dst_rects[i].x2 = ceil(ox + x2);
+ dst_rects[i].y1 = floor(oy + y1);
+ dst_rects[i].y2 = ceil(oy + y2);
+ }
+
+ pixman_region32_fini(dst);
+ pixman_region32_init_rects(dst, dst_rects, nrects);
+ free(dst_rects);
+}