Classic Computer Magazine Archive CREATIVE COMPUTING VOL. 9, NO. 12 / DECEMBER 1983 / PAGE 97

Graphics and music for the color computer. (evaluation) Joe Devlin.

Graphics and Music for the Color Computer


Semidraw is a sketching program that allows you to draw on the screen of your television or monitor. It is called Semidraw because it makes use of the Color Computer semi-graphics modes. Along with the advantages of text coexistent on the screen with graphics, the semi-graphics mode allows you to have up to 15 colors onscreen at one time, rather than the maximum of four available in other Color Computer graphic modes.

The problem with the semi-graphics mode is that it provides a rather strangely shaped pixel, one that is much longer than it is tall. The creators of Semidraw have evened out this monstrosity by creating a cursor that is relatively large, but symmetrical.

The program starts with a detailed semigraphics drawing lesson for the novice. If you prefer, you can skip this part and start with a blank screen or recall a previously saved image.

Semidraw can apply color to the screen wherever the cursor can be moved. The cursor is moved around the screen using either the right joystick or the arrow keys on the keyboard. To draw or set a dot simply press the joystick button or the @ key. The color of the cursor indicates the color of the dot you will set. You can change the color of the cursor with the left joystick or by pressing the C key and the number of the color you want.

Three Graphics Resolutions

There are three graphics resolutions to choose from. All three modes are 60 pixels across, but mode 8 is 64 pixels high, mode 12 is 96 pixels high, and mode 24 is 192 pixels high. Depending upon the graphics resolution you have chosen, you can create up to six different screens of drawings. These screens appear to be contiguous; if you move your cursor too far down, you end up on the next screen. This is nice for setting up animations or when you are so inspired that just one screen cannot express the creativity you feel. You can sketch three pictures in mode 8, then change to mode 24, and all three pictures will appear on the screen at once, side by side.

Text With Graphics

The program allows the mixture of text with graphics, using the built-in character generator in the Color Computer. To enter the lettering mode, set the cursor where you want the text to begin, press the L key and type away. The resulting characters are green on a black background.

If you don't want to use black as the background color or if you want to erase an entire page, press the K key followed by the number of the color you wish the background to be.

Your creations can be saved to or recalled from tape or disk at any time. Once created, an image can be recalled, altered, and resaved in its altered form. This facility makes simple animation a snap. To change the pages of the screens, press the number key corresponding to the page you wish to view. To copy a page over, press the R key. You will be asked which pages you want copied and where you want them copied.

Simple animation effects may be achieved by pressing the P key. This causes the program to cycle through each available page. The speed of animation can be controlled with the right joystick.

A copy of your artwork can be dumped to your Radio Shack Line Printer VII or VIII or to a NEC 8023 or C. Itoh 8510. Press S and follow the prompts. The resulting picture will be printed sideways and will simulate different colors with differing dot patterns.

Because large parts of the program are written in Basic the program can be annoyingly slow. This is especially true during the animations, which are not particularly animated. Speed is also something of a problem just in moving the cursor across the screen and entering commands. Response to keyboard input is slow, and sometimes keystrokes are ignored--probably because they are missed.

The cassette or disk you buy includes several sample screens that can be displayed and altered to your specifications. I thought the animated rainbow was a bit too cute, but it does illustrate the animation potential of Semidraw.


In sum, Semidraw is a well designed package for the amateur artist. It can be used to simulate animation, although if you are planning to include animation in a game you are writing you will probably have to store the screens and then display them using your own software. Although parts of the program could use speeding up, overall the features and design of Semidraw provide a nice outlet for your creative urges.

Synther 7

I have a confession to make. I sing in the shower: I imitate instruments on my drive to work: and I got a kick out of playing with Synther 7. Synther 7 is a real-time "music' synthesizer for the Radio Shack Color Computer. It is designed for the musical ignoramus like myself who nevertheless drums and hums when no one is listening.

Load the program and your initiation into the world of music begins. Bypass the offer of a detailed description of the workings of the package and the screen will be your guide to your instrument.

At the top of the screen is a series of black and white keys. Under the picture of the piano keyboard is a listing of the letters and numbers on the computer keyboard which correspond to musical notes. The top row on the keyboard corresponds to the black keys on a piano and the second row to the white.

Six bar graphs at the left of the screen indicate the options you have for shaping the sound of the notes played on your keyboard. A block of text in the lower center indicates your choice of musical instrument, and a horizontal bar on the lower right displays the pitch range of that instrument.

Five Instruments:

The five instruments from which the musician can choose are the gamba, hogfife, jninni, krumphorn, and lute. I am not sure how accurate the sound of most of these instruments is, partly because I am not sure how many of them exist in real life. Each instrument is accessed with a single keystroke.

Five more instruments, labeled simply alternate instruments, can be generated by hitting the/key. Each instrument is interesting in its own way.

The tonal range of each instrument is graphically represented at the lower right of the screen. Only two octaves of the total range can be accessed from the keyboard at any one time. You select which two octaves will play by pressing the up-arrow and K keys.

Feel Free To Experiment

Each instrument also has its own predefined character. You are as free to change the character of the notes as you are to change octave selection. Thus, notes can be made louder or softer, or shorter or longer, and twang can be added or taken away--all with the stroke of a few keys.

The attack of the notes, which is the fervor with which the note begins, can be adjusted. Notes can be set so they either decay or hold steady. Vibrato can be set to be pronounced or subtle. A set of six bar graphs on the lower left of the screen indicates how each note characteristic is currently set. There are many variables to play with. Feel free to experiment. An almost infinite range of effects is possible. With each graph element is a number which may be copied so that you can re-create interesting discoveries.

Synther 7 does have its shortcomings. The most serious is that it has only a single voice; only one note can be played at any one time. Although the music you play can be saved on cassette, it is the sound and not the coding that is being saved. This means that while you can play your creations back, you cannot insert them into other programs. Nor can you alter the nature of the music once it is recorded except by rerecording it from scratch.

Obviously, Synther7 is not for the professional musician. But who cares if the music produced sounds more like a Looney Tune melody than the Boston symphony. Synther7 is fun. Synther7 requires no special external hardware. Music emanates from the speaker of your TV or monitor or from the speaker of your cassette recorder.

It's shame you can't hear the Ode to Synther7 I have been composing. I think it is the best thing I have done since the imitations of Elvis Presley imitating Bob Dylan I did last week in the shower.

Products: Computerware Semidraw (computer program)
Computerware Synther 7 (computer program)