Commodore 128D - Page 108

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When you first run your program, you will want to clear the graphics
screen for the first time, so set c equal to 1 in the GRAPHIC com
mand. If you run it a second time, you may want to leave your picture v j
on the screen, instead of drawing it all over again. In this case, set c
equal to 0.
The s parameter specified where the start of the text screen in split-
screen mode is to begin at the line after the specified line number. If
you omit the s parameter and select a split-screen graphic mode (2 * (
or 4), the text screen portion is displayed in rows 20 through 25; the
rest of the screen is bit mapped. The s parameter allows you to
change the starting line of the text screen to any line on the screen, J j
ranging from 0 through 25. A zero as the s parameter indicates the
screen is not split, and is all text. A 25 as the s parameter indicates
the screen is not split, and is all graphics. [ j
The final GRAPHIC command parameter is CLR. When you first
issue a bit-map graphic command, the Commodore 128 allocates a
9K area for your bit-mapped screen information. 8K is reserved for
the data for your bit map and the additional 1K is dedicated for the
color data (video matrix). Since 9K is a substantial block of memory,
you may want to use it again for another purpose later on in your
program. This is the purpose of GRAPHIC CLR. It reorganizes the
Commodore 128 memory and gives you back the 9K of memory that
was dedicated to the bit-map screen, so you can use it for other
purposes.
The format for GRAPHIC CLR is as follows:
GRAPHIC CLR
When using this format, omit all other GRAPHIC command
parameters.
Add the following command to your program. It places the C128 in
standard bit-map mode and allocates an 8K bit-map screen (and 1K
of color data) for you to create graphics.
40 GRAPHIC 1,1
The second 1 in this command clears the bit-map screen. If you do
not want to clear the screen, change the second 1 to 0 (or omit it
completely).
NOTE: If you are in bit-map mode and are unable to return to
the text screen, press the RUN/STOP and RESTORE keys at the
same time, or press the ESC key followed by X, to return to the
100 USING C128 MODE—Color, Animation and Sprite Graphics Statements