Sets the clipping rectangle of a bitmap.
Each bitmap has an associated clipping rectangle, which is the area of
the image that it is ok to draw onto. Nothing will be drawn to positions
outside this space. This function sets the clipping rectangle for the
specified bitmap. Pass the coordinates of the top-left and bottom-right
corners of the clipping rectangle in this order; these are both inclusive,
i.e. set_clip_rect(bitmap, 16, 16, 32, 32) will allow drawing to (16, 16)
and (32, 32), but not to (15, 15) and (33, 33).
Drawing operations will be performed (at least partially) on the bitmap as
long as the first coordinates of its clipping rectangle are not greater
than the second coordinates and its intersection with the actual image
is non-empty. If either condition is not fulfilled, drawing will be turned
off for the bitmap, e.g.
set_clip_rect(bmp, 0, 0, -1, -1); /* disable drawing on bmp */
Note that passing "out-of-bitmap" coordinates is allowed, but they are
likely to be altered (and so the coordinates returned by get_clip_rect()
will be different). However, such modifications are guaranteed to preserve
the external effect of the clipping rectangle, that is not to modify the
actual area of the image that it is ok to draw onto.
The following threads each have code containing this keyword:
Note: You can click on the numbers to jump directly to the posts that reference this page.
The following projects include source code containing this keyword: