Programming Bit Image Graphics - Oki 182 Handbook

_ _ _ _ _ _ _ _ _ _ CHAPTER 3 PROGRAMMING
PROGRAMMING BIT IMAGE GRAPHICS
You can also write a program that prints a graphics image directly,
without transferring it from the display screen. This section explains
how to do this using BASIC statements.
Your printer prints graphics images in successive columns of eight
dots. The LPRINT statement that tells the printer to do this has three
components:
• The control code sequence that puts the printer into graphics
mode,
• The number of columns to be printed, and
• The coded data that tells the printer which dots to print in each
column.
First, we discuss each part separately, then put them together.
There are four modes of bit image graphics available with the
IBM-compatible MICROLINE. They differ in horizontal resolution,
or density. This indicates how close together the dots are; it is
measured by the number of dots per inch. All modes have a
vertical resolution of 72 DPI. For reference, the diameter of a dot
is 1/72 inch. The modes are discussed in more detail in the next
section on control codes.
The maximum width of a graphics image is 8 inches for the ML 182.
1 . Control Codes
A graphics LPRINT statement begins with a control code that tells
the printer to print a graphics image. Each graphics mode has a dif ­
ferent control code.
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