In this case graphics coordinates are used -- notice the numbers are separated

by semicolons unlike the VDU 28 command.

You can see the graphics window by typing:

GCOL 0,130 RETURN

CLG RETURN

Although graphics are now displayed only within the window, the whole screen

is still used for text. To completely separate text and graphics we must set up

both a graphics and a text window. Create a text window below the graphics

window by typing:

VDU 28,5,31,34,28 RETURN

Change the background text colour to red:

COLOUR 129 RETURN

CLS RETURN

Type in some MOVE and DRAW commands. The text is displayed within the

text window, and any lines drawn only appear within the graphics window.

After a VDU 26 command the whole screen is used for text and graphics once

again, so return things to normal by typing:

VDU 26 RETURN

Note that using a MODE command has the same effect as it automatically

destroys all windows.

Printing text at graphics positions

TAB is used to print characters on the screen at any text coordinate. It is

sometimes helpful to position text more accurately on the screen than PRINT

TAB allows, especially if graphics are also used.

In modes in which graphics can be used, text can be printed at graphics

coordinates after a VDU 5 command. This program gives a three dimensional

effect by printing the same message twice and slightly off-setting the second set

of characters which are printed in a different colour:

10 MODE 1

20 PRINTTAB(16,15)"H e l l o"

30 VDU 5

40 GCOL 0,1

50 MOVE 516,540

60 PRINT''H e l l 0"

70 VDU 4

C 26