Classic Computer Magazine Archive ANTIC VOL. 4, NO. 11 / MARCH 1986


Bright, colorful, random geometric displays


Since Logo is the only language included with early 520STs, many owners have been struggling with a new vocabulary. Dyed-in-the-wool BASIC programmers might find Logo a little strange but, like anything else, once you understand how it works, you can do a lot with it.
   Logo is a procedural language. This means programs are broken up into small, individually defined tasks-or procedures. This will make your programs easier to read and debug. Each procedure can call another procedure. In what is known as recursive programming, procedures can even call themselves.
   Logo Moderne is a set of Logo procedures that will create an electronic work of art on your ST's low-resolution color screen. It draws several sets of geometric figures, randomly picking the various attributes, such as screen position, size, line width, color, and fill pattern.


Although Listing 1 is designed for low resolution, you may wish to use medium resolution while you are actually typing it in. Whichever you choose, save a copy of the program and get your ST into low resolution before loading the listing into memory.
   Before going any further, you might want to click on the Buffr Grph option on the Setting Menu. This will save your artwork in a buffer so that it can be re-displayed should a Dialog or Menu Box appear over it.
   When the program is in memory type MODERNE from the Dialog Window and press [RETURN]. Click the upper-right box of the Graphics Display Window to get the full effect.
   When the drawing is finished, the Dialog Window will reappear. You can get rid of the pesky critter by clicking anywhere within the Display Window.
   To create a new picture, pull down the Run Menu and click on Run Buffer. Voila! Another original!
   You might want to experiment with Logo Moderne. Try changing the CANVAS procedure to limit the number of colors. If you don't care for your palette, call up the Control Panel and change it-for example, try several different shades of blue.
   If you would like to have more-or less-objects drawn, change the REPEAT 5 [OBJECTS] value in the MODERNE procedure. Or, take out the REPEAT statement altogether, call OBJECTS, then assign a REPEAT value to each individual procedure within OBJECTS. This way you can vary the quantity of each particular object that is drawn.
   You can change the sequence in which objects are drawn. To avoid certain objects being overlaid, put them at the end of the procedure.
   Play around with different RANDOM statements. Some of them, like Index, Style and Color values for SETFILL can't get any larger. But most can be altered in some way.
   Enjoy your Atari masterpieces-each one a guaranteed original. Who knows, maybe STs will start appearing in galleries across the country, exhibiting this latest form of electronic art.

Bud Cool is from Hazelwood, Missouri and Logo Moderne is his first program published in Antic.

Listing 1   MODERNE