Random MacArt in Basic

By Amy Barger, Waunakee, WI

Random MacArt is an MS Basic program which creates catchy modern art designs. Each design is unique and exciting with a general movement expressed. These designs can be created almost instantaneously and have many potential uses for decorating, entertainment, and experimentation. Figure 1 shows a design created by Random MacArt.

Fig. 1 Our random art program in Basic

Using Random MacArt

Random MacArt is an easy program to use. To create a design, press COMMAND R and watch the random designs appear; the computer screen will seem alive! Each design will finish on its own. After you have admired or printed the design, click the mouse button once and a fresh new design will appear. When you have created all the designs you want, you can save or print them. To save a design, type COMMAND SHIFT 3. This saves the screen. In order to print a design, make sure the printer is on, then type COMMAND SHIFT 4. This will print the active window. Stopping or listing the program follows the normal MS Basic conventions.

How Random MacArt Works

The program is simple to understand. We will begin with the first line and go through the program. RANDOMIZE TIMER bases random numbers according to the time on the Macintosh's internal clock. If you were to use this program again at exactly the same time that you had used it on a previous day, so that the clock reading was the same, the same design would be created. You will most likely never get the same design twice.

DIM shows the highest number of elements in the array specified in the statement. In this program it is set to 10 for both x and y. The DIM statement is really not necessary here because a maximum value of 10 is always assumed for an otherwise unspecified subscript, but it is good practice to routinely use DIM statements.

In order for designs to be created one after another without having to rerun the program each time, a loop is used. When the computer gets to the last line of the program, the statement GOTO loop instructs it to return to the line with the statement "loop".

The WINDOW statement opens a window on the screen within which the design will be drawn. The window-ID, one in this case, specifies the window's identification number. The commas show that there is no title for this window. (If there had been, it would have been in quotes between the two commas.) The numbers in parentheses specify the window size. The x values for this window are 10 and 502, and the y values are 26 and 332. Following the comma, the number three indicates that the type of window desired is an one-line border window.

Following the WINDOW statement is a FOR/NEXT loop that is used in determining ten random values of x and y, labeled as x(n) and y(n). The statements in the loop are executed with n increasing by one each cycle. RND(1) returns a random number in the range of 0 to 1. For x, the random number is multiplied by 440, and for y, by 254. INT converts the numbers into integers, and then two is added to each. These latter steps insure that the design is drawn within the window's border. NEXT n forms the loop. After ten iterations the loop is exited.

Next, nested FOR/NEXT loops are used to create the design based on the array of random x(n), y(n) values generated previously.

The LINE statement draws a straignt line between the coordinates pairs (x(n-1)+s*4), (y(n-1)+s*4) and (x(n)+s*4), (y(n)+s*4). For example, with n=0 and s=0 the statement becomes LINE (x(1),y(1))-(x(2),y(2)). NEXT n forms a loop so that the successive points will be connected. The LINE statement following NEXT n connects the last point with n=10 back to the first point with n=1.

Without the FOR/NEXT loop on s, the design would look flat and simple. On every pass through the s-loop an identical design is created with (x,y) points displaced four pixels away from the previous design. By the time the loop is completed the result consists of 13 superimposed designs.

The WHILE/WEND loop allows the user to view the design until the mouse button is depressed. MOUSE(0) is the state of the mouse button, with MOUSE(0)=0 indicating that the button has not been clicked and MOUSE(0)=-1 indicating that it has been. When the user clicks the mouse the WHILE statement will end with the WEND. (WEND means WHILE end). The colon allows two separate statements to be entered on one line. The CLS line clears the screen and the last line returns to "loop" to start a new design.

Possible Modifications To Improve Random MacArt

When you have tried the program and printed out some intricate designs, the next step is to experiment. If you would like your designs to have more sides to make them appear even more complex, or smaller to make them appear simpler, the number of random numbers to be chosen can be changed. Remember that if you increase the number of random numbers to be used, the DIM statement must also be increased. If you would prefer a larger or smaller screen, the window size numbers in the parentheses can be altered. Three other types of windows can be obtained by changing the number three after the parentheses to one, two, or four. Try altering the numbers which are multiplied and added to the random numbers. This will position your designs in different parts of the screen and make your designs larger or smaller. The distance between each line of your designs can be altered by changing the value the variable s is multiplied by. To create more or less lines, change the value of the variable s. As you can see the possiblities of this program are endless! Have a good time and experiment freely to make the most interesting designs possible. Try running this under the new compiler and see if you can notice any speed improvements.

RANDOMIZE TIMER
DIM x(10),y(10)

loop:
WINDOW 1,,(10,26)-(502,332),3
FOR n=1 TO 10
    x(n)=INT(RND(1)*440)+2
    y(n)=INT(RND(1)*254)+2
NEXT n

FOR s=0 TO 12
    FOR n=2 TO 10
        LINE (x(n-1)+s*4,y(n-1)+s*4)-(x(n)+s*4,y(n)+s*4)
    NEXT n
    LINE (x(10)+s*4,y(10)+s*4)-(x(1)+s*4,y(1)+s*4)
NEXT s

WHILE MOUSE(0)=0:WEND
CLS
GOTO loop