TURBO PASCAL |
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11. How can I customize the text characters to my own liking?Q: How can I customize the text characters to my own liking? A: As far as I know, text- mode characters are hard-coded, and cannot be customized at all unless you have an EGA or VGA adapter. But you can always retrieve the bitmap information for the ascii characters from your PC. The bitmap table for the lower part of the character set (0-127) starts at memory position $F000 and ends at $FA6E. The upper part is not at a fixed memory location. The pointer to the memory address of upper part of the ascii table (provided that graftabl has been loaded) is at an address $007C. One way of saying this is that the segment address of the upper part's memory location is at $007E, and its offset at $007C. Going into more details is beyond the scope of this posting. If you want more information see Michael Tischer (1992), PC Intern System Programming, "Selecting and Programming Fonts", pp. 197-210. It also has information on a remotely related task of using sprites (pp. 305-373), a concept familiar from the days of the Commodore 64 games programming. For another reference to customizing characters see Kent Porter (1987), Stretching Turbo Pascal, Chapter 12, and Kent Porter & Mike Floyd (1990), Stretching Turbo Pascal. Version 5.5. Revised Edition. Brady, Chapter 11. If you are interested in a demonstration of utilizing the bitmapped character information (no source code available), take a look at the demo in the garbo.uwasa.fi anonymous FTP archives file ftp://garbo.uwasa.fi/pc/ts/tsdemo16.zip (or whatever version number is current). Turbo Pascal also supports what is called stroked fonts (the .chr) files which draw characters instead of bitmapping them. The user should be able to write one's own .chr definitions, but I have no experience nor information on how this can be done. There is something called bgikit10.zip which has facilities for making fonts and adding graphics drivers. The problem is that I cannot make it publicly available, since I think that it is not PD. I am still missing the information. Unfortunately, it is not even the only case where I encountered the fact that Borland does not seem at all interested in the UseNet users' queries about the status and distributability of their material. (From Leonard Erickson Leonard.Erickson@f51.n105.z1.fidonet.org Well, you can *also* do it if you have a Hercules Graphics Card Plus or Hercules InColor card (as far as I know, the only cards that implemented Hercules RamFont 'standard'). And you can modify the upper 128 characters on a CGA card. BTW, the RamFont cards are *nice* pity it appeared too late to become a standard. It's a *lot* more flexible than EGA/VGA fonts (I can have several *dozen* fonts resident).) |
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