Docs » Autodocs » graphics.library » ReadPixel
ReadPixel -- read the pen number value of the pixel at a
specified x,y location within a certain RastPort.
penno = ReadPixel( rp, x, y )
d0 a1 d0:16 d1:16
LONG ReadPixel( struct RastPort *, SHORT, SHORT );
Combine the bits from each of the bit-planes used to describe
a particular RastPort into the pen number selector which that
bit combination normally forms for the system hardware selection
of pixel color.
rp - pointer to a RastPort structure
(x,y) a point in the RastPort
penno - the pen number of the pixel at (x,y) is returned.
-1 is returned if the pixel cannot be read for some reason.
WritePixel(), <graphics/rastport.h>
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