Throughout the rest of this section only mode 135 will be discussed, but all

comments apply equally to mode 7.

This program demonstrates the text colours available in mode 135:

10 MODE 135

20 PRINT "This";CHR$(129);"shows how a control code"

30 PRINT "only effects the";CHR$(130);"characters"

40 PRINT "after it on the";CHR$(131);"same";CHR$( 129);"line."

The PRINT statement at line 20 prints some text containing a series of

invisible control codes. Each code takes up a character position, so the words

are printed with spaces between. The codes affect the way the remaining

characters on that particular line are displayed. For example, printing

CHR$(129) before 'shows' makes the computer display the text in red,

CHR$(l30) causes the text after it to be printed in green, and so on.

Printing any of the ASCII codes 129 to 135 affects the colour of any characters

printed after the code on the same line. Try:

PRINT CHR$(130)

which prints in green. A full list of the teletext control codes is given in

Appendix 2.

The colour of text can be changed directly from the keyboard. Hold down

and at the same time press the red function key f1. This prints the control

code 129. Any characters you type on the same line will now be displayed in

red. Pressing and any of the function keys f1 to f7 gves a different

colour for any text printed afterwards on the same line.

You can also make text flash:

PRINT CHR$( 36);"Flash";CHR$(137);"no flash";CHR$(136);"flash"

Flashing coloured text can be produced by using two control codes:

PRINT "Flashing";CHR$(129);CHR$(136);"red"

The codes each occupy a character position, so the words are printed separated

by two spaces.

Again, the same effects are possible using the function keys. SHIFT and f8

print the control code for flashing, SHIFT and f9 print the non-flashing code.

Double height characters can be printed using CHR$(14l):

10 MODE 135

20 PRINT CHR$(141);"Double height"

30 PRINT CHR$(141);"Double height"

C 62