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getpixel(3)			Allegro	manual			   getpixel(3)

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

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  bit-
       maps  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 4.4.2			   getpixel(3)

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | SEE ALSO

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