set_clip_rect(3) Allegro manual set_clip_rect(3)NAMEset_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 posi‐
tions 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 draw‐
ing 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, draw‐
ing 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 ALSOget_clip_rect(3), add_clip_rect(3), set_clip_state(3),
get_clip_state(3), ex12bit(3), excamera(3)Allegro version 4.4.2 set_clip_rect(3)
