Oki ML3390, Руководство пользователя

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Chapter 11: IBM - Graphics
11-9
The number of dot columns
specified by means of n
1
and
n
2
must not exceed the
maximum number of dot
columns per line for the
respective graphics density.
Following the command for activating the graphics mode in the re-
spective density are two parameters designated n
1
and n
2
which
communicate to the printer the number of graphic columns to be
printed. In order to determine the values of these numbers, you
need to define the number of graphic columns per line to be printed
and divide this by 256. The value n
2
here is the integer component of
the result, n
1
the remainder printed out as a whole number.
If, for example, 400 graphic columns are to be printed, n
1
and n
2
are
computed as follows:
n
2
= integer (400/256) in the example: n
1
= 1
n
1
= 400 - 256 * n
2
in the example: n
2
= 144
The last part of a graphics instruction contains numerical data
which contains the actual image information.
Each column is represented by a byte containing 8 bits in which a 1
corresponds to a dot to be printed. A 0 shows that no dot is to be
printed at this position. The highest dot is the MSB (most significant
bit), the lowest dot the LSB (least significant bit). To each column in
a line is assigned a numerical value. Add the values of the column
positions at which dots are to be printed, and insert the total sum
for each column beginning from the left in your program. An ex-
ample for the calculation of column sums is to be found on the pre-
vious pages.
After calculating the sums for each column (s
1
, s
2
, etc.), the complete
instruction reads:
LPRINT CHR$(27); “K”; CHR$(144); CHR$(1);
CHR$(s
1
); CHR$(s
1
); ...; CHR$(s
400
)
The format is the same for all graphics. Merely the commands for
opening the graphics in the respective resolutions and the maxi-
mum number of column bytes vary. The value in a column which
portrays a certain dot pattern is always the same irrespective of the
graphics resolution.