diff options
Diffstat (limited to 'common/common.c')
-rw-r--r-- | common/common.c | 22 |
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 |