set_clip_rect - Sets the clipping rectangle of a bitmap. Allegro game programming library.

       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.

       set_clip_rect - Sets the clipping rectangle of a bitmap. Allegro game programming library.

get_clip_rect(3alleg4),   add_clip_rect(3alleg4),    set_clip_state(3alleg4),    get_clip_state(3alleg4),
       ex12bit(3alleg4), excamera(3alleg4)

Allegro                                           version 4.4.3                           set_clip_rect(3alleg4)

#include<allegro.h>voidset_clip_rect(BITMAP*bitmap,intx1,inty1,intx2,inty2);