Commodore Plus 4 - Page 105

SQUARES,
CIRCLES,
POLYGONS,
AND
PAINTING
Drawing
Rectangles
Using the DRAW command, you can draw pictures by plotting many
dots or lines. To draw a square, you can use the command DRAW 1,0.0
TO 100.0 TO 100,100 TO 0,100 TO 0,0 (plotting each endpoint of the
square) or you can just use the BOX command.
THE BOX COMMAND
Your Plus'4 includes a command to make it easier to draw squares and
other rectangular shapes. The BOX command lets you pick the points
of 2 opposite corners of the square. To duplicate the same box as in
the above example, just use BOX 1,0,0,100,100- The number 1 again
means that you want to draw and not erase. The next four numbers are
the coordinates of the box's opposite corners, {0,0} at the upper-left
corner and (100,100) near the middle of the screen.
The BOX command can form any rectangle just by changing the cor
ners. You can even rotate the box by specifying an angle (in degrees)
after the last coordinate, like this: BOX 1,50,50,100,100,45. The box is
rotated 45 degrees clockwise.
If you would like to draw a solid box instead of just the outline, you just
add a comma 1 after the angle. A solid box at the center of the screen is
shown as BOX 1,100,50,220,150,,1. Notice that you need a comma to
take the place for the angle, even though you don't want the box rotated.
Some typical forms of the BOX command are:
COMMAND
BOX on, columni, row!, column2, row2
BOX on. con, rowl, col2, row2, angle
BOXon.coM, row1.col2, row2, , fill
BOX off, col1,row1, col2, row2, angle, fil
EFFECT
Outline
Rotated
Solid box
Erase area
of screen
Here are a couple of programs that use the BOX command:
Don't forget to type NEW then hit RETURN before entering each
program, and press return after typing in each line.
10 COLOR 0,1
20 COLOR 1,2
30 GRAPHIC 2,1
40A=RND(l)*20 + 10
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