Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!samsung!zaphod.mps.ohio-state.edu!caen!uflorida!haven!adm!news From: CDCKAB%EMUVM1.BITNET@cunyvm.cuny.edu ( Karl Brendel) Newsgroups: comp.lang.pascal Subject: (R)Re: Graphic-screen to disk Message-ID: <25083@adm.brl.mil> Date: 21 Nov 90 14:59:41 GMT Sender: news@adm.brl.mil Lines: 65 In article <11529@j.cc.purdue.edu>, Albert Zhou writes: >In article <25074@adm.brl.mil> CDCKAB%EMUVM1.BITNET@cunyvm.cuny.edu ( Karl > Brendel) writes: >> >>In article <11518@j.cc.purdue.edu>, Albert Zhou >> writes: [deleted] >>I'm inclined to believe that either you don't have a "true" CGA, or your >>monitor doesn't display the image clearly, or you are being deceived by > ^^^^^^^^^^^^^^^^^ >>the simplicity of your displayed pattern. When I run your progra >^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ >>(which, admittedly, I am doing on a VGA, using the CGA driver), it i [deleted] >Now I've inserted a more complex pattern instead of the straight into the >same program. It still worked the same way as I described before. Here is >the program: [deleted] (Just to keep it straight, > is from Albert Zhou's last, and >> from my previous. ) Well, you've ruled out the simplicity factor. That just leaves the "true" CGA and monitor display factors. :) On this end, it is still _very_ clear that a portion of the image is not restored when you do the assignments to MyBuffer1 and MyBuffer2, and that it is when you do the assignment to AnotherBuffer. It is well documented that the _entire_ (i.e., text _and_ graphics) CGA video buffer starts at $B800. Refer to _Programmer's_Problem_Solver_ _for_the_IBM_PC,_XT_&_AT_, Jourdain, Brady/Prentice Hall, ISBN 0-89303-787-7: page 205: ;---CALL THE ROUTINE: MOV AX,0B800H ;point to graphics buffer page 234 (excerpt): Mode Type Buffer start ==== ==== ============ 4 B800 5 B800 6 B800 (That's all of the CGA graphics modes. ;) ) +-------------------------------------------------------------------------+ | Karl Brendel Centers for Disease Control | | Internet: CDCKAB@EMUVM1.BITNET Epidemiology Program Office | | Bitnet: CDCKAB@EMUVM1 Atlanta, GA, USA | | ILink/RIME: KARL BRENDEL phone 404/639-2709 | | CIS : 73307,3101 fts 236-2709 | | GEnie: K.BRENDEL Home of Epi Info 5.0 | +-------------------------------------------------------------------------+