IBM 4400 manual Bit Image Programming Format, Sample Single Density Bit Image Graphics

Bit Image Programming Format

The number of data bytes and the n1, n2 definition must be equal. If too few data bytes are sent, printing does not begin until sufficient data is received. Any characters following n1 and n2 are interpreted (and plotted) as data until the n1, n2 definition is satisfied.

If excess data is received, only the defined amount is plotted. Excess data is interpreted as printable characters or control codes. The maximum number of data bytes (when using 132 column paper) that can be included in the DATA portion of the program statement varies according to the operating mode.

At 60 dpi, single density = 792 bytes double density = 1584 bytes quadruple density = 3168 bytes

Note that bit image data printed in Letter Gothic (DP) with the paper set to advance less than 1/6 inch causes data on successive lines to overlap.

A detailed description of the individual Bit Image control codes with examples is provided in the appropriate protocol chapter.

The following sample program written in BASIC produces Single Density Bit Image graphics of the pattern shown below. The 7 data bit pattern is repeated 40 times. The printed result of running the program is shown in Figure 30.

10 LPRINT "Single Density Bit Image Graphics"

20 LPRINT CHR$(27);"K";CHR$(24);CHR$(1);

30 FOR N=1 TO 40

40 RESTORE

50 FOR I=1 TO 7

60 READ R

70 LPRINT CHR$(R);

80 NEXT I

90 NEXT N

100 DATA 73, 146, 36, 255, 36, 146, 73

110 LPRINT

Figure 30. Sample Single Density Bit Image Graphics

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