Date   : Thu, 22 Sep 2011 11:10:34 +0100
From   : robert@... (Rob)
Subject: Text conversion ?

On 22 September 2011 10:45, Darren Grant <darren.grant@...> wrote:
>
> On 22 Sep 2011, at 07:00, Sprow wrote:
>
>> Unless I misremember aren't the Domesday articles shown in MODE 7? The
>> leading space would thus allow the article to be loaded directly into screen
>> memory, and for the text colour (or double height) selected on the fly by
>> poking over the leading space?
>> Sprow.
>
> I think you are right, they are probably mode 7, sorry to sound dense but
?what do you mean by 'poking over the leading space' ?

It's possible to change colour of text on a line on screen by
overwriting the single byte at the start of the line with a colour
code.  e.g:

MODE 7:PRINT " Hello there":FOR I%=128 TO 137:?&7C00=I%:REPEAT UNTIL GET:NEXT

The Domesday screens I have seen have invariably used colour as a form
of highlighting, e.g. page of yellow text with occasional words in
red.  The codes to change colour are in the 0-31/128-159 range, and
occupy a character position on a Mode 7 screen, and display (usually)
as a space.  If the text you have has already been converted from this
format into "plain text", you will have lost the colour/highlighting
information, and it's pretty usual to replace such codes with a space,
otherwise you get wordsbumpingtogether.  As a consequence, you'll get
a space at the start of the line where the colour code was.

Rob