#D4 #D5#D6#D7[=0h[1mf

If you can read this, then you are not TYPEing this file to the screen
on a BBC Master 512. If you haven't already done this, then try it. Use
the /P command-line switch. At the DOS command line enter:

                TYPE DEMOCTLS.TXT /P

After you have seen what happens, then come back and look at the file
with your word-processor. You will see that it is a pure text file,
apart from included "Escape sequences".

Because of the way that COMMAND.COM pauses after every 23 new-line
characters, the file is divided into 23-line blocks. This is the reason
for the numerous empty lines.

The real content of the file starts here:
[0m#B[22;1HM[2;8HControl Codes Demonstration
[6;4HThis file should be TYPEd to the[7;4Hscreen using the "/P" option.
[9;4HIt shows some of the things that[10;4Hcan be done by including control[11;4Hcode sequences within a text file.
[14;4HWe begin by selecting a 40-column[15;4Hscreen mode, drawing a pretty[16;4Hborder, shrinking it by one line
[17;4H(to allow space for the "Strike[18;4Ha key" message) and putting some[19;4Htext in it like this.
[24;1H
[5;2H#AF [6;2H#AF [7;2H#AF [8;2H#AF [9;2H#AF [10;2H#AF 0
[11;2H#AF [12;2H#AF [13;2H#AF [14;2H#AF [15;2H#AF [16;2H#AF 0
[17;2H#AF [18;2H#AF [19;2H#AF [20;2H#AF [21;2H#AF [22;2H#AF 0
b1[5;5HNow we will try some colour
[6;5Hvariations.
b2[8;5HThis is another colour. Four at
[9;5Honce are possible in this mode.
b3[11;5HWe could try rbold text in
[12;5Hb:various b9colours, b3but it is
[13;5Hrather hard to read.
[15;5HIf we set the default to black
[16;5Hthen we cannot see the text.
[17;5HSo let's hide the usual
[18;5H"Strike a key" message.
[20;3Hb1You will need to b2press b:somethingb1
[21;3Hto go on with the next bit.
Hb0





[24;1H
[5;2H#AF [6;2H#AF [7;2H#AF [8;2H#AF [9;2H#AF [10;2H#AF 0
[11;2H#AF [12;2H#AF [13;2H#AF [14;2H#AF [15;2H#AF [16;2H#AF 0
[17;2H#AF [18;2H#AF [19;2H#AF [20;2H#AF [21;2H#AF [22;2H#AF 0
#D4#D5#D6#D7
b1[5;4HPalette changes are possible too.
b2[7;4HThey can be used, as they can
[8;4Hon the normal BBC Micro to make
[9;4Ha significant amount of material
[10;4Happear suddenly.
[12;4HAll of this text which has just
[13;4Happeared was printed on the last
[14;4Hscreen. You have just made it
[15;4Hvisible with a colour change.
[17;4HA slightly different effect, I
[18;4Hthink you will agree, from what
[19;4Hhappens when the text comes
[20;4Hdirect from disc to screen.
[22;10Hb1Press a key to go on.
Hb0



[24;1H
H
#D6















Hb0




[24;1H
[5;2H#AF [6;2H#AF [7;2H#AF [8;2H#AF [9;2H#AF [10;2H#AF 0
[11;2H#AF [12;2H#AF [13;2H#AF [14;2H#AF [15;2H#AF [16;2H#AF 0
[17;2H#AF [18;2H#AF [19;2H#AF [20;2H#AF [21;2H#AF [22;2H#AF 0
#D4#D5#D6#D70
b9[2;8H#C;b3
[6;5HAny combination of the normal
[7;5HBBC Micro colours is possible
[8;5Hincluding the b2flashingb3 ones
[9;5Hif you have any reason to use
[10;5Hthem.

[13;5HNow press any key to say
[14;5Hfarewell to this display, and
[15;5Hto turn the cursor back on.
[16;5H(Had you noticed it was off?)
Hb0






[24;1H
HI
I            I            I            I
I            I            I            I
I            I            I            I
I            I            I            I
I            I            I            I
I            I            I            I
I            I            I            I
I            I            I            I
I            I            I            I
#D7 b3e
Right. That's got rid of the border.
Did you like the way it went?B
We have seen a number of the things
that are possible in a 4-colour,
40-column mode.B
It is probably time to go on to
something else at this point, so:




[12;1H
#D00#D17
[=2h
#D4 #D5#D6#D7
HNow we are in an 80-column mode.B
In practice, this is likely to be something you use rather more often than the
40-column one. Most programs assume that it is selected before you even get
them started.B
On a genuine PC this would have 8 colours available for both the foreground and
the background. Also the characters could appear in both normal and intense
colours, and they could be made to flash.B
The 512, because of the way that it uses a squeezed down version of the host's
Screen Mode 3, only allows two colours. Any attempt to change the background
colour c1results in text appearing in inverse video like this.c0 Flashing text does
not work and changing the foreground colour has no effect. rThe machine pretends
to provide an intense colour by using this special bold font. (It is actually
the normal font "thickened up" in a horizontal direction. Unfortunately,
legibility is not improved.) c1The bold font can be used along with inverse video
in this way.c0uB
All of these effects can be produced in TYPEd files using control sequences, as
you see. Various other things are possible in addition, however, so:H


[22;1H
E#D04Once again, palette changes are possible.

The restrictions on the way the character attributes combine mean that you
cannot actually hide text (apart from blanking the screen completely by making
the foreground and background the same). We cannot, therefore, hide the "Strike
a key" message. We can, though, arrange things so that it is somewhere else,
like just under this line:
H














[7;1Hp
q[8;1H#Cp
[9;1HYou may have noticed that it was in inverse as well.B
Another thing that we can do is to spread out the rows vertically. We shall do
this next, but the effect is not exactly smooth so

[31CBand look for p***q ... p***q to find your place.f




H




H






[13;1H
#}
[14;1Hj#Az kp***q This is where you pressed a key p***qB
When you spread out the screen like this, especially when you have changed the
physical colour of the background, you can distinguish the lines and count
them quite easily. If you do, you will find that there are 25. Normally you
cannot use the bottom one in TYPEd files. There are ways of getting material
into it, though. See the bottom line of this page.
[25;1HwThis is on line 25 - Switching off line wrap means we can even use the last cellH














[21;1H
zE#{#D00#D12#B[2;28HControl Codes Demonstration[5;4HWe are almost at the end of the demonstration now.
[7;4HA good many of the facilities available by use of control sequences
[8;4Hhave been seen. This border, for example, is drawn automatically with
[9;4Ha single control sequence. However, it takes up the whole screen, and
[10;4Hif we leave it like this it is going to be spoiled by the "Strike a
[11;4Hkey" message. (That message always starts in the left-most column.)
[13;4HThe way round this problem is to shrink the border, and put the[14;4Hmessage underneath. Just so that you can see it happening, we shall
[15;4Hshrink it by several lines, and slow it down a bit.f[16;4Hj                                                                       k                                                                       k                                                                       k                                                                       k                                                                       k                                                                       k
[16;4Hj                                                                       k                                                                       k                                                                       k                                                                       k                                                                       k                                                                       k
[16;4Hj                                                                       k                                                                       k                                                                       k                                                                       k                                                                       k                                                                       k
M[17;4HOne line . . .[16;4Hj                                                                       k                                                                       k                                                                       k                                                                       k                                                                       k                                                                       k
[16;4Hj                                                                       k                                                                       k                                                                       k                                                                       k                                                                       k                                                                       k
[16;4Hj                                                                       k                                                                       k                                                                       k                                                                       k                                                                       k                                                                       k
[17;1HM[17;4HTwo lines . . .[16;4Hj                                                                       k                                                                       k                                                                       k                                                                       k                                                                       k                                                                       k
[16;4Hj                                                                       k                                                                       k                                                                       k                                                                       k                                                                       k                                                                       k
[16;4Hj                                                                       k                                                                       k                                                                       k                                                                       k                                                                       k                                                                       k
[17;1HM[17;4HThree lines . . .[16;4Hj                                                                       k                                                                       k                                                                       k                                                                       k                                                                       k                                                                       k
[16;4Hj                                                                       k                                                                       k                                                                       k                                                                       k                                                                       k                                                                       k
[16;4Hj                                                                       k                                                                       k                                                                       k                                                                       k                                                                       k                                                                       k
[17;1HM[17;4HFour lines . . .[16;4Hj                                                                       k                                                                       k                                                                       k                                                                       k                                                                       k                                                                       k
[16;4Hj                                                                       k                                                                       k                                                                       k                                                                       k                                                                       k                                                                       k
[16;4Hj                                                                       k                                                                       k                                                                       k                                                                       k                                                                       k                                                                       k
[17;1HM[17;4HFive lines - I think that will do. [18;4HWatch it happening if you go through again.e[22;1H
E#D17zThis demonstration has hopefully given you some idea of the kind of things
that can be done simply by inserting control sequences into a file.

Now you have seen it as a TYPEd file, have a look at it with your word-
processor or text-editor. This should show you the full text, including the
control sequences. You will be able to work out for yourself exactly how the
sequences have been made to produce the effects. With a bit of imagination
(and discretion) you will be able to enhance your own text files assuming,
of course, that you are expecting them to be displayed only on a Master 512.

The demonstration has not shown everything that is possible. To find out what
control sequences are recognized by the Master 512's version of DOS-Plus and
what they do, read the accompanying file M512CTLS.DOC.

We are at the end of the file now, so everything is returned to normal, with
one exception. See what happens when you press one of the red function keys.

If you want to get the function keys back to their usual values then you have
two options. The crude one is to re-boot. The preferable one (?) is to read
the article in M512CTLS.DOC and work out for yourself how to do it!6