MASTERING THE ATARI 1020 PLOTTER
Tutorial with demonstration programsby Kris Cruz
Learn how to use the graphics power of the inexpensive Atari 1020 Color Plotter. This tutorial article provides a complete explantion of the 1020 commands plus four short demonstration lisitngs. The BASIC programs work on all Atari computers of any memory size, with disk or cassette.
The Atari 1020 Color Plotter is a very useful and inexpensive printing tool. It lends itself to a wide variety of applications from geometry and physics diagrams to home finance graphs or even just high tech doodling! (See tbe October, 1985 Antic for more information about tbe 1020, including where it can be obtained. ANTIC ED)
There are two general modes of operation text and graphics. In the text mode you have a choice of 20, 40 or 80 column text in four different colors. You can also have the text rotated 90, 180, 270 or 360 degrees. This feature can be used to produce bright and colorful banners.
In the graphics mode you can use X,Y coordinates to plot graphs. You can also specify where you would like the axis drawn for your graph. Basically, if you are familiar with plotting and drawing on the screen, then you should have little trouble using the 1020 graphics mode. Figure 1 summarizes the text and graphics commands.
Figure 1 INSTRUCTION FORM MODE GRAPHICS ESC ESC CTRL G - TEXT DEFAULT AT CHANNEL OPENING TEXT A TEXT FROM GR. 20 COL. TEXT ESC ESC CTRL P TEXT 40 COL. TEXT ESC ESC CTRL N TEXT 80 COL TEXT ESC ESC CTRL S TEXT HOME H GRAPHICS PEN COLOR C (VALUE 0-3) GRAPHICS LINE TYPE L (VALUE 1-15) GRAPHICS 0=SOLID - - DRAW DX,Y GRAPHICS MOVE MX,Y GRAPHICS ROTATE TEXT Q(0-3) GRAPHICS (Text to be rotated must start with P) INITIALIZE I GRAPHICS (Sets current X,Y as HOME or 0,0) RELATIVE DRAW JX,Y GRAPHICS (Used with Init.) RELATIVE MOVE RX,Y GRAPHICS (Used with mit.) CHAR. SCALE S(0-63) GRAPHICS
The commands are not difficult to use. But they must be sent in a manner which the plotter can understand. First, you must OPEN a channel to the 1020. Type: OPEN #2,8,0,"P:".
This opens a channel for output to the printer in the same manner as any other device. You are now automatically in the 40 column text mode. Any text you send out through a PRINT #2 statement will be printed in 40 columns. Next type: PRINT #2;"[ESC][ESC][CONTROL ]P". Now everything is printed 20 columns wide.
For 80 column text, type: PRINT #2; [ESC] [ESC] [CTRL] S. To print different colors, press the color button between printings or type: PRINT #2; [ESC] [ESC] [CONTROL] G [RETURN]. And then type: PRINT #2;"C(any # 0-3)" [RETURN] PRINT #2;"A". Notice how the pen barrel is rotated to change pens. Numbers for the different pen colors are shown below:
# COLOR 0 Black 1 Blue 2 Green 3 Red
There are nine commands within the graphics mode. OPEN a channel to the plotter and type: PRINT #2;"[ESC] [ESC] [CONTROL] G". This sets the plotter in the graphics mode.
The DRAW command is much like DRAWTO in BASIC. But with the plotter, X can be from 0 to 480 and Y can be from -999 to 999. The line is drawn from the current position to XY Type: PRINT #2;"D450,0". This draws a black line across the paper and stops.
To have the pen barrel return to its HOME position, type: PRINT #2;"H". If you want dotted lines, type: PRINT #2;"L(any value 1-15)". Then type: PRINT #2;"D450,-10".
To plot points, you must be able to lift the pen from the paper while moving it. This requires the MOVE command. Type: PRINT #2;"M200,-200". The paper moves up and the pen moves to the center. However, no line is drawn. Now add 1 to either the X or Y and DRAW. Type: PRINT #2;"D200,-201". This is how points can be plotted. But usually the pen is left down to show the shape of the function being plotted.
For demonstrations of fundamental plotter patterns, type in Listings 1-4, checking each line with TYPO II. SAVE a copy of each listing before you RUN it.
Listing 1 shows how the functions of SIN, COS and TAN look when plotted. You will notice in lines 15, 30 and 50 that an asterisk [*] can be used to send more than one command in a single PRINT statement.
Listing 2 draws two groups of concentric circles which cross each other. Listing 3 draws spiraling triangles. It does this by changing the radius and the points where it connects the triangle.
Listing 4 draws two squares and connects each of the corners with a line. It can easily be modified to do the same for other shapes, by changing the step and the data representing which points to connect.
As you can see, there is much you can do with the Atari 1020 Plotter. Until recently, such features cost upwards of $2,000, but now Atari users can get the same kind of high tech plotting for under $50. And even if you aren't interested in making graphics or charts in four colors, for much less than the cost of a dot-matrix printer you could purchase a 1020 simply to list your programs.
Airman First Class Kristofer Cruz is currently stationed in Texas.
PRINT 'N DRAW Terrific Software 17 St Mary's Court Brookline, MA 02146 (617) 232-9686 $14.95, 48K disk
Reviewed by ERIC CLAUSEN
Print 'n Draw is a new commercial utility for the Atari 1020 Color Plotter. It is easy to use, yet sophisticated and offers many practical features at a reasonable price. (For more about available 1020 software, see the September, 1985 Antic.)
The program creates a variety of banners, pie charts and text styles directy from the main menu, providing all necessary prompts. In addition, 26 sample picture files are included, many of them quite detailed. Graphics Magician picture files can also be dumped to the plotter via Print 'n Draw.
This software is recommended for ages 8 to adult. But play-testing with a 6-year-old revealed that even younger children may find the package to be a fascinating drawing tool. I personally found myself (age 29) enjoying the program as well!
Print 'n Draw is written in BASIC and is well error-trapped. The owner's manual, while quite friendly and useful, is not really needed because the program is so easy to use.
It should be understood that Print 'n Draw is not capable of the sophisticated graphics produced by some of the more expensive and complex plotting programs available for Atari. The intent of this program is to provide instant access to the basic functions of the 1020 plotter with a minimum of fuss.
Print 'n Draw is highly recommended for all 1020 owners, particularly those with children, who want a simple but effective plotter program.