Re: ANN: bitmap shape capture for 8-bit graphics

[Linards Ticmanis <ticmanis@gmx.de>]

Anthony Lawther wrote:

> That'd be why lots of programs that want to do this sort of thing use 
> the Open and Closed Apple keys as modifiers not the Control key. Even 
> the Mac didn't (and still doesn't) use the Control modifier key for 
> these functions but uses the Command (Open Apple) key.

Of course these don't exist on a II/II+. That leaves the ESC key as a 
possible alternative.

Regarding Control-C, the check for it is hard-coded in the Applesoft 
ROMs, so you can't disable it as-such. But you can trap it with an ONERR 
statement. It'll produce error code 255 IIRC. So you could write a 
routine for getting characters from the keyboard that goes about like this:

temporarily set up an ONERR GOTO*
GET character
deactivate ONERR GOTO*
RETURN

ONERR destination:
check if error code is 255
if not:
  PRINT error message
  END
if so:
  character = chr$(3)
  clean up ONERR mess*
  RETURN



*see Applesoft II Basic Programmer's Reference Manual.

--
Linards Ticmanis