diff options
| -rw-r--r-- | chickadee/math/rect.scm | 26 |
1 files changed, 18 insertions, 8 deletions
diff --git a/chickadee/math/rect.scm b/chickadee/math/rect.scm index 155fc19..b4f1ba4 100644 --- a/chickadee/math/rect.scm +++ b/chickadee/math/rect.scm @@ -281,14 +281,24 @@ while keeping the rect centered around the same point." (define-inlinable (rect-union! rect1 rect2) "Update RECT1 in-place to completely cover the area of RECT1 and RECT2." - (let ((x1 (min (rect-left rect1) (rect-left rect2))) - (x2 (max (rect-right rect1) (rect-right rect2))) - (y1 (min (rect-bottom rect1) (rect-bottom rect2))) - (y2 (max (rect-top rect1) (rect-top rect2)))) - (set-rect-x! rect1 x1) - (set-rect-y! rect1 y1) - (set-rect-width! rect1 (- x2 x1)) - (set-rect-height! rect1 (- y2 y1)))) + (cond + ;; If rect1 has no area, just copy rect2. + ((and (zero? (rect-width rect1)) + (zero? (rect-height rect1))) + (rect-copy! rect2 rect1)) + ;; Ignore rects that have no area. + ((and (zero? (rect-width rect2)) + (zero? (rect-height rect2))) + *unspecified*) + (else + (let ((x1 (min (rect-left rect1) (rect-left rect2))) + (x2 (max (rect-right rect1) (rect-right rect2))) + (y1 (min (rect-bottom rect1) (rect-bottom rect2))) + (y2 (max (rect-top rect1) (rect-top rect2)))) + (set-rect-x! rect1 x1) + (set-rect-y! rect1 y1) + (set-rect-width! rect1 (- x2 x1)) + (set-rect-height! rect1 (- y2 y1)))))) (define-inlinable (rect-clip! rect1 rect2) "Update RECT1 in-place to be the overlapping region of RECT1 and RECT2. |