[PATCH] media: v4l2-rect.h: fix v4l2_rect_map_inside() top/left adjustments

From: Helen Koike
Date: Tue Dec 17 2019 - 15:00:46 EST


boundary->width and boundary->height are sizes relative to
boundary->left and boundary->top coordinates, but they were not being
taken into consideration to adjust r->left and r->top, leading to the
following error:

Consider the follow as initial values for boundary and r:

struct v4l2_rect boundary = {
.left = 100,
.top = 100,
.width = 800,
.height = 600,
}

struct v4l2_rect r = {
.left = 0,
.top = 0,
.width = 1920,
.height = 960,
}

calling v4l2_rect_map_inside(&r, &boundary) was modifying r to:

r = {
.left = 0,
.top = 0,
.width = 800,
.height = 600,
}

Which is wrongly outside the boundary rectangle, because:

v4l2_rect_set_max_size(r, boundary); // r->width = 800, r->height = 600
...
if (r->left + r->width > boundary->width) // true
r->left = boundary->width - r->width; // r->left = 800 - 800
if (r->top + r->height > boundary->height) // true
r->top = boundary->height - r->height; // r->height = 600 - 600

Fix this by considering top/left coordinates from boundary.

Fixes: ac49de8c49d7 ("[media] v4l2-rect.h: new header with struct v4l2_rect helper functions")

Signed-off-by: Helen Koike <helen.koike@xxxxxxxxxxxxx>

---

include/media/v4l2-rect.h | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/media/v4l2-rect.h b/include/media/v4l2-rect.h
index c86474dc7b55..8800a640c224 100644
--- a/include/media/v4l2-rect.h
+++ b/include/media/v4l2-rect.h
@@ -63,10 +63,10 @@ static inline void v4l2_rect_map_inside(struct v4l2_rect *r,
r->left = boundary->left;
if (r->top < boundary->top)
r->top = boundary->top;
- if (r->left + r->width > boundary->width)
- r->left = boundary->width - r->width;
- if (r->top + r->height > boundary->height)
- r->top = boundary->height - r->height;
+ if (r->left + r->width > boundary->left + boundary->width)
+ r->left = boundary->left + boundary->width - r->width;
+ if (r->top + r->height > boundary->top + boundary->height)
+ r->top = boundary->top + boundary->height - r->height;
}

/**
--
2.24.0