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Off-Screen Pixel Map
- To: info-mcl
- Subject: Off-Screen Pixel Map
- From: email@example.com (Klaus Kansy)
- Date: 28 Aug 91 12:56:19 GMT
- Newsgroups: comp.lang.lisp.mcl
- Organization: GMD, St. Augustin, F.R. Germany
Hello Macintosh and Lisp users,
I am trying to realize drawing into an off-screen pixel map
in the MCL2.0b1 environment, as described for C and Pascal
in the Macintosh Technical Notes #120.
But 'copybits' does not seem to work as it should. The pixels
are correct in the memory (which I checked with a simple
routine that interpretes bytes in memory as color pixels), but
I cannot produce them on the screen.
This is the trouble statement in Pascal:
CopyBits (BitMapPtr (MyCGrafPtr^.portPixMap^)^,
bRect, destRect, 0, nil)
This is my version in MCLisp:
(#_CopyBits (rref MyCGrafPtr :cgrafport.portpixmap)
(rref (wptr MyCWindow) :window.portBits)
bRect destRect 0 (%null-ptr))
This statement only produces random black and white patterns,
a bitmap obviously.
Who has done such a 'copybits' call successfully in Lisp?
I would be relieved to get a reply!
Postfach 12 40
Thanks so much in advance, I am really close to despair!