GRAPH-ED

by Daniel Azzopardi



[The program in GRAPH-ED.TAP includes the corrections from the July issue.]



The pick of this month's rather meagre bunch of entries was sent in by

Daniel Azzopardi. You may remember his entry in November's Pitstop,

that won him fifty smackeroonies, and he's onto another nice little

earner. Daniel's winning entry this month is a nice little utility

which is, in the words of its author "interesting and useful, unlike

many message scrollers." Hmmm, yes, I think he's made his point.



Anyway, the utility in question is a graphics editor which enables

anyone who's not quite up to sprite level to design and use up to 256

UDGs in their programs. This is a good step up from the

not-nearly-enough 21 that are normally allowed. The difference here is

that, instead of being stored in the normal UDG memory space, these

are chucked in at 25600 (the other end of the RAM, if I remember

rightly) and take up to 2K's worth when all 256 UDGs are used.



There are two listings, a BASIC program as usual and a Hex dump. Type

in the BASIC and SAVE "Graph.Ed" LINE 500. Then enter the Hex and save

with SAVE "GraphCode" CODE 50000,704. All this has to be done in 48K

mode on 128Ks.



By all accounts, this Hex business has been giving a number of people

hassle, not least Peter Cadegan who lives just down the road from me

in Corsham. Just for you Peter, and anyone else who's stumped, here's

a more detailed than usual guide to entering Hex ...



* Type in the Hex Loader and save it on a separate tape for future use.

* RUN it, enter the Start Address (the first five digit number in the listing).

* When prompted, enter the line of Hex (16 characters).

* Enter the checksum on the right, repeat for the next line of Hex and so on.

* At the end, enter STOP instead of a line of Hex and save the created code

  after the BASIC.

* If you still don't understand try reading the article in Spec Tec, issue 68.

  (Simply turn to Back Issues on page 49 to order your copy. No fuss,

  no tears -just simple! Ed)



That's enough of that, back to business! All the control keys for

Daniel's program are listed when the program is running, so I won't

bother writing them all out here. After you've generated your graphics

and pressed Z they'll be saved in normal UDG format to 25600. By

normal UDG format I mean 8 bytes each, each byte representing a line

and each bit representing a pixel when expressed in binary form. And

that's it. (Phew! Linda) If you've got something better lying around,

send it in and win 50 quid!