Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!snorkelwacker!apple!amdahl!drivax!frotz From: frotz@drivax.UUCP (Frotz) Newsgroups: comp.sys.ibm.pc.programmer Subject: Re: PORTABLE Direct Screen access? Keywords: screen access, portability Message-ID: Date: 29 Mar 90 03:11:54 GMT References: <321@pallas.athenanet.com> Sender: frotz@drivax.UUCP Reply-To: frotz@drivax.UUCP Organization: Digital Research, Monterey CA Lines: 51 dgl292@pallas.athenanet.com (Doug Lee) writes: ] There has been some discussion in this group recently on the subject of ] direct screen access. I am attempting to write a program which, if possible, ] must directly access text display memory while remaining portable across a ] wide variety of DOS machines. ] I am specifically interested in reliable ways to determine the location of ] screen memory for a given system and in ways of handling the possibility of ] non-80X25 displays. I will use BIOS calls if necessary, but I am attempting ] to avoid the apparent headache of saving/restoring video states (I ] initially thought one could simply save/restore the cursor position, but the ] only code example I have also directly accesses registers of EGA ] (I think) boards where applicable for an unknown purpose). ] Information and advice would be MOST appreciated. If it is easier to do this ] using BIOS calls, I would also be interested to know what (if anything) I ] must do in addition to saving the cursor position to insure success with ] the various adapters in current--and, hopefully, future--use. Well, I am about half done with the 1.4/1.5 PCcurses merge... (should be around another 2-3 weeks...;-( Then I still need to contact Bjorn Larsson and coordinate with him... (Bjorn, are you out there?) PCcurses 1.5 will have stock EGA/VGA support (standard (EGA)80x43, (VGA)80x28, (VGA)80x50, and normal 80x25) support. It has the option of direct video memory writes vs. BIOS video writes. Colors. Pads. Printing the contents of a window/pad to LPT1: via the BIOS. Resizable windows. Mostly X/Open Curses Interface compliant (exceptions are the newterm() calls that handle the I/O streams)... [Relatively] legally established Public Domain status (via Pavel Curtis and Bjorn Larsson)... Adapter Combinations: VGA Mono/Color EGA Mono/Color MCGA Mono/Color CGA MDA At one time I had added support for the 66-line MDS Genius Monitor with Direct Video Memory Writes. That was sweet! Unfortunately it collided with another EGA clone card, so it was removed. It was relatively trivial to add support for these weird modes, the problem is unique adapter detection;-( -- Frotz@Digital Research, Incorporated amdahl!drivax!frotz Graphics Business Unit (408) 647-6570 (msg) 70 Garden Court, B15 (408) 649-3896 Monterey, California 93940 Ask for John Fa'atuai [This is News. This is your brain on News. Any questions?]