From: Jack Klein <jackklein AT spamcop DOT net>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: cursor
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On Fri, 10 Nov 2000 12:20:30 +0200, "Eli Zaretskii"
<eliz AT is DOT elta DOT co DOT il> wrote in comp.os.msdos.djgpp:

> > From: Jack Klein <jackklein AT spamcop DOT net>
> > Newsgroups: comp.os.msdos.djgpp
> > Date: Fri, 10 Nov 2000 04:52:43 GMT
> > > 
> > > You mean, turn off the BIOS cursor and draw a character instead of it?
> > > That's quite tedious, especially if you want the cursor to blink.
> > 
> > When you move the cursor onto some position of the display, build a
> > character pixel map consisting of the character with your vertical
> > line merged in, and set an unused character value (perhaps 255, which
> > is a blank) to use this bit map.
> 
> This is possible on a PC today as well.
> 
> > Hook the timer and on every fourth timer alternate between the actual
> > char value and the modified char value (i.e., 255), to get about a 2.5
> > Hz blink rate.
> 
> This is what I call ``tedious''.
> 
> > The last few versions of the Norton Utilities for DOS offered text
> > mode "graphics" including an arrow mouse pointer as an option on
> > computers with an EGA or higher, which was much more complicated.
> > Even though the mouse pointer was the size of a text character, they
> > allowed it to move pixel-by-pixel, which means it could be covering
> > varying parts of up to four characters at any given time.
> 
> The mouse pointer is a different beast, we were talking about the text
> cursor.

I know the mouse pointer is different, I just wanted to point out a
commercial product some readers that might be familiar with that used
a similar technique.

Jack Klein
-- 
Home: http://jackklein.home.att.net