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authorwm4 <wm4@nowhere>2020-05-22 14:17:46 +0200
committerwm4 <wm4@nowhere>2020-05-22 14:17:46 +0200
commit1be32529b161d6c67d51004062ee4e6280036fb3 (patch)
treecc1b665725adbf6e1af21c6cfb8140831eb2c67d /common/common.c
parent320fa3bbe73c57e2ba5633a865b6997c1901b4b2 (diff)
downloadmpv-1be32529b161d6c67d51004062ee4e6280036fb3.tar.bz2
mpv-1be32529b161d6c67d51004062ee4e6280036fb3.tar.xz
common: add helper for subtracting rectangles
Not sure if generally useful; the following commit uses it.
Diffstat (limited to 'common/common.c')
-rw-r--r--common/common.c22
1 files changed, 22 insertions, 0 deletions
diff --git a/common/common.c b/common/common.c
index 0552bddda4..6607f95c3c 100644
--- a/common/common.c
+++ b/common/common.c
@@ -126,6 +126,28 @@ bool mp_rect_equals(struct mp_rect *rc1, struct mp_rect *rc2)
rc1->x1 == rc2->x1 && rc1->y1 == rc2->y1;
}
+// Compute rc1-rc2, put result in res_array, return number of rectangles in
+// res_array. In the worst case, there are 4 rectangles, so res_array must
+// provide that much storage space.
+int mp_rect_subtract(const struct mp_rect *rc1, const struct mp_rect *rc2,
+ struct mp_rect res[4])
+{
+ struct mp_rect rc = *rc1;
+ if (!mp_rect_intersection(&rc, rc2))
+ return 0;
+
+ int cnt = 0;
+ if (rc1->y0 < rc.y0)
+ res[cnt++] = (struct mp_rect){rc1->x0, rc1->y0, rc1->x1, rc.y0};
+ if (rc1->x0 < rc.x0)
+ res[cnt++] = (struct mp_rect){rc1->x0, rc.y0, rc.x0, rc.y1};
+ if (rc1->x1 > rc.x1)
+ res[cnt++] = (struct mp_rect){rc.x1, rc.y0, rc1->x1, rc.y1};
+ if (rc1->y1 > rc.y1)
+ res[cnt++] = (struct mp_rect){rc1->x0, rc.y1, rc1->x1, rc1->y1};
+ return cnt;
+}
+
// This works like snprintf(), except that it starts writing the first output
// character to str[strlen(str)]. This returns the number of characters the
// string would have *appended* assuming a large enough buffer, will make sure