Drawing functions such as
draw-line
and
draw-ellipse
modify pixels, but you cannot assume that they have exactly the same effect on all platforms. Some platforms might put pixels below and to the right of integer coordinates
(x y)
while others may center the pixel at
(x y)
.
This applies to all the drawing functions which are documented in the Graphics Ports chapter of the
LispWorks CAPI Reference Manual
- see the entries for functions with names beginning
draw-
.
CAPI User Guide (Unix version) - 30 Aug 2011