Date   : Thu, 18 Jan 1996 14:28:31 +0000 (GMT)
From   : amh15@... (Alan Hart)
Subject: Re: TTX codes

> > Anyone know what the teletext codes hold/release graphics and
> > conceal do? I guess they are related to hiding info on the
> > screen which you occasionally see on some Ceefax/Oracle pages.
> > 
> I'm not sure about the conceal code does, but as far as I can remember, 
> hold graphics changes all subsequent lower case charcters to graphics 
> until the end of the current text line or until the release character is 
> encountered.
> 
> Please feel free to correct me, anyone, if I've got this wrong - it's 
> been a while since I've done any MODE 7 stuff. :-(

No, that's what the graphics colour characters 144-150 do.

I know what hold/release does, though, roughly, as we've discussed this 
here before.

Hold sets all the characters 144-150 on the rest of the line to appear as 
graphics characters. The graphics character that appears in each case will
be the previous graphics character to appear on that line - I think.

What this allows you to do is generate a solid line of graphics characters 
that changes colour without gaps. If you see what I mean.

Alan

Alan Hart - amh15@... - Cambridge University, UK - +44 1223 515460