Fx-286e dot graphics, Specifying graphics line length – Genicom GEK 00031B User Manual

Page 150

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Chapter 6. Epson FX286-E Emulation

GEK-00029A

150

FX-286E DOT GRAPHICS

Dot graphics allows you to print individual dots at any position on
the page, and thus to print pictures as well as text. While in graphics

mode, emphasized, double-strike. expanded, underlined, subscript
and superscript remain as set, but are inactive.

The FX-286e printer doesn't adjust the line feed increment
automatically on entering graphics. If contiguous vertical graphics is
desired, then set the line feed increment to 8/72 inch before starting

graphics and then reset it when finished. See Line Spacing
Commands on page 134.

An FX-286e graphics control sequence starts with an escape
combination that sets the graphics density (ESC K, L, Y, or Z).
followed by a 2-byte header that shows the number of subsequent
bytes that are to be interpreted as graphics data. The format of the

sequence is:

ESC (density) (n1) W) (data) ... (data)

Since this control sequence has no terminator, you need to specify
exactly in the header the number of bytes that you want to be
interpreted as graphics. If there are fewer graphics data bytes than
specified in the header, then the printer treats subsequent text and

control codes as graphics. In that case, carriage returns and line
feeds are often ingested as graphics data.

On the other hand, if there are more graphics data bytes than
specified in the header, then the printer interprets excess bytes as
text or control codes. Mils can also produce very interesting results.

Specifying Graphics Line Length

The two bytes (n1, n2) specify the total number of image bytes that
follow; n2 is the most significant byte.

total number of image data bytes = n1 + (n2 x 256)
Example: To print 5 inches of graphics at ESC K density, which is 60
dpi, then:

total number of bytes = 5 inches x 60 dpi - 300

300/256 = 1 with a remainder of 44
n1 = 44

n2 = 1

The sequence sent to the printer (shown in BASIC) would look like:

CHR$(27);CHR$"K";CHR$(44);CHR$(1);CHR$(v1);. . . CHR$(v300);

where v1 through v3OO are image data bytes.

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