Radio Shack TRS-80 Operation Manual page 77

Computer Graphics Operation Manual
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GPRINT is used to write text characters to the Graphics
Screen. This is the easiest way to display textual data on
the Graphics Screen. Characters are displayed starting at
the current
(~,y)
coordinates and going in the direction
specified by the most recently executed LOCATE call. If no
LOCATE call was executed prior to the GPRINT call, a
direction of
~
is assumed.
GPRINT will only print text characters (see Appendix C of
the Model III Operation and BASIC Language Reference
Manual). Each character displayed in the
~
or 2 direction
uses an 8 X 8 pixel grid; each character displayed in the I
or 3 direction uses a 16 X 8 grid. Executing this command
will set the current
(~,y)
coordinates to the end of the
last character that was displayed.
Displaying text in direction
~
engages a wraparound feature.
If the end of a line is reached, the display will be
continued on the next line. If the end of the screen is
reached, the display will be continued at the beginning of
the screen without scrolling. If there is not enough room to
display at least one character at the current (x,y)
coordinates, a GRAPHICS ERROR will result. When displaying
text in other directions, an attempt to display text outside
the currently defined screen will cause a GRAPHICS ERROR to
be given.
GRPINI
Graphics Initialization Routine
GRPINI is the graphics initialization routine. This function
must be called before any other graphics calls are made in
FORTRAN.
Example
CALL GRP IN I
( l )
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