initial commit.

1 files changed, 46 insertions, 0 deletions

diff --git a/rect.c b/rect.c
new file mode 100644
index 0000000..c72c66e
--- /dev/null
+++ b/rect.c
@@ -0,0 +1,46 @@
+#include "maths.h"
+#include "rect.h"
+
+Rect* rect_clip(Rect* r, const Rect* c) {
+	int n;
+	int x = r->x, y = r->y;
+	if ((n = c->x - r->x) > 0) {
+		r->w -= n;
+		r->x += n;
+	}
+	if ((n = c->y - r->y) > 0) {
+		r->h -= n;
+		r->y += n;
+	}
+	if ((n = x + r->w - (c->x + c->w)) > 0)
+		r->w -= n;
+	if ((n = y + r->h - (c->y + c->h)) > 0)
+		r->h -= n;
+	return r;
+}
+
+Rect* rect_clips(Rect* r, Rect* s, const Rect* c) {
+	int n;
+	int x = r->x, y = r->y;
+	if ((n = c->x - r->x) > 0) {
+		r->w -= n;
+		r->x += n;
+		s->w -= n;
+		s->x += n;
+	}
+	if ((n = c->y - r->y) > 0) {
+		r->h -= n;
+		r->y += n;
+		s->h -= n;
+		s->y += n;
+	}
+	if ((n = x + r->w - (c->x + c->w)) > 0) {
+		r->w -= n;
+		s->w -= n;
+	}
+	if ((n = y + r->h - (c->y + c->h)) > 0) {
+		r->h -= n;
+		s->h -= n;
+	}
+	return r;
+}