NAME¶
set_clip_rect - Sets the clipping rectangle of a bitmap. Allegro game
programming library.
SYNOPSIS¶
#include <allegro.h>
void set_clip_rect(BITMAP *bitmap, int x1, int y1, int x2, int y2);
DESCRIPTION¶
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.
SEE ALSO¶
get_clip_rect(3alleg4),
add_clip_rect(3alleg4),
set_clip_state(3alleg4),
get_clip_state(3alleg4),
ex12bit(3alleg4),
excamera(3alleg4)