getpixel(3)                     Allegro manual                     getpixel(3)



NAME
       getpixel - Reads a pixel from a bitmap. Allegro game programming
       library.

SYNOPSIS
       #include <allegro.h>


       int getpixel(BITMAP *bmp, int x, int y);

DESCRIPTION
       Reads a pixel from point (x, y) in the bitmap.

RETURN VALUE
       Returns -1 if the point lies outside the bitmap (ignoring the clipping
       rectangle), otherwise the value of the pixel in the color format of the
       bitmap.

       Warning: -1 is also a valid value for pixels contained in 32-bit
       bitmaps with alpha channel (when R,G,B,A are all equal to 255) so you
       can't use the test against -1 as a predicate for such bitmaps. In this
       cases, the only reliable predicate is is_inside_bitmap().

       To extract the individual color components, use the getr() / getg() /
       getb() / geta() family of functions.


SEE ALSO
       putpixel(3), _getpixel(3), is_inside_bitmap(3), getr(3), getg(3),
       getb(3), geta(3), ex12bit(3), exalpha(3), exflame(3), exlights(3)



Allegro                          version 4.2.3                     getpixel(3)
