is_inside_bitmap - Tells if a point is inside a bitmap. Allegro game programming library.

       Returns non-zero if point (x, y) lies inside the bitmap. If `clip' is non-zero, the function compares the
       coordinates  with  the  clipping  rectangle,  that  is  it  returns non-zero if the point lies inside the
       clipping rectangle or if clipping is disabled for the bitmap. If `clip' is zero,  the  function  compares
       the coordinates with the actual dimensions of the bitmap.

       is_inside_bitmap - Tells if a point is inside a bitmap. Allegro game programming library.

set_clip_rect(3alleg4), set_clip_state(3alleg4), getpixel(3alleg4)

Allegro                                           version 4.4.3                        is_inside_bitmap(3alleg4)

#include<allegro.h>intis_inside_bitmap(BITMAP*bmp,intx,inty,intclip);