Genicom GEK 00031B - Manual (Page 259)

GEK-00029B 5000 Series Programmer’s Manual 259
DECGRA (") Set Raster Attributes: Defines the pixel aspect ratio, overriding Ps1
of the protocol selector. DECGRA also defines the extent (size) of the
raster. Level 3 printers ignore the extent parameters.
Format
“ Pn1 ; Pn2 ; Pn3 ; Pn4
Description
This command must precede picture-definition information requiring
an aspect ratio: sixel printable characters (sixel data, 3/15-7/14), the
Graphics New Line (DECGNL) command and, by extension, Graphics
Repeat Introducer (DECGRI) and Graphics Carriage Return
(DECGCR). Otherwise, this command is ignored. If multiple DECGRA
sequences are received, only the last one is accepted.
Parameter Description
Pn1 Pixel aspect ratio numerator
Pn2 Pixel aspect ration denominator
Pn3 Horizontal extent
Pn4 Vertical extent
Pn1 describes the vertical size of a pixel in an arbitrary distance unit.
Pn2 describes the horizontal size of a pixel in the same distance unit.
For example, to define a pixel to be half as wide as it is tall, send 200;
100 for Pn1 and Pn2.
The pixel aspect ratio times the horizontal grid size (Ps3 of the
protocol selector) yields the vertical grid size.
Pn3 and Pn4 define the horizontal and vertical extent, respectively, in
pixels. Level 3 printers ignore these parameters. Page composition
software can include these parameters for compatibility with video
terminals.
Error Handling
If Pn1 or Pn2 is greater than 32K, the value 32K is used. If Pn1 or
Pn2 is 0 or omitted, the printer sets it to 1.
The maximum aspect ratio supported by the printer is 1: 10 or 10: 1
(after reducing the ratio to the lowest possible format).
The maximum parameter implemented for DECGRA is 999 (decimal).
If the Set Raster Attributes sequence is received after a sixel printable
character or another sixel control code is received, the command is
ignored.
Any additional parameters received are ignored.