SCREEN-COPYING
By Paul Newman
on Spectrum

The Spectrum manual states that you can't PEEK or POKE the screen. Well, you
can and this short demonstration program shows this, by copying the top third
of the screen to the middle third. Whilst not very inspiring in itself, this
should give you enough of a clue to a routine that will PEEK any PRINT
position and return the true character value, which of course, SCREEN$ will
not do.

Enter the short program and put anything you like in the PRINT line 10. RUN
will copy the top third to the middle and erase the top as it does so. You
will see that the screen is built in the same manner as loading the screen
area (when a screen-save has been made). This should provide enough clues
also as to which bytes to PEEK or POKE. An example would be to copy anything
on a given line to another, or to build the true SCREEN$ value of a graphic
character. Another example might be mirror-imaging of lines or individual
characters.
