Graphics Function Set Commands - Printronix S828 Programmer's Manual

Programmer Manual
Ym-coordinate origin. When the block is within an overlay that is invoked using an IO command, WIC bytes
11 through 13 and 15 through 17 specify the offset from the X-coordinate and Y-coordinate origin specified
in the IO command.
Bytes C through D must equal 0 degrees scan line direction and bytes E through F must equal 90 degrees
scan line sequence direction. The Coordinate Type byte 10 is not used to modify the image direction.
Write Image (WI)
Length D63D
This command transmits a block of image data to the printer. A sequence of one or more Write Image
commands follows the Write Image Control command and terminates with an End command.
The total number of bits of image is equal to the product of the number of source scan lines and the
number of bits on each scan line. Thus, the number of bytes sent is:
(Bytes 4 through 5 x bytes 6 through 7 of the WIC command) divided by 8
Note: If this calculation yields a fractional remainder, round the result to the next whole number. The
DATA parameter bytes contain the image bit string.
End (END)
For a description of the End control, see "End (END)".

Graphics Function Set Commands

The graphics function set contains the commands and data controls for presenting graphic pictures on a
logical page, page segment, or overlay area on the physical medium. The following commands are the
graphics function set:
Command Code
WGC D684
WG D685
END D65D
Graphics is a data type the printer uses to present line art picture drawings in a graphics block area on a
page. A sequence of drawing orders produce arcs, lines, fillets, character strings, markers, and other
elements that define the drawing. These orders, grouped into one or more segments, present the picture.
The control unit sends a Write Graphics Control command to the printer to establish the control
parameters and initial drawing conditions for presenting the picture data. The picture segments themselves
are sent to the printer as data in one or more Write Graphics commands.
Knowing how the graphics picture is developed allows an understanding of the relationship between the
Write Graphics command and the Write Graphics Control command. The following pages explain the
drawing order coordinates, the graphic medium presentation space, and the graphic block area.
Drawing Order Coordinate System
The drawing orders specify graphics in an abstract space rather than directly on the page. This allows
repositioning graphics on a page without changing the drawing orders. Coordinates (Graphics X and Y)
specify the position of the graphic.
Chapter 5 IPDS Programming Information
Flag Correlation ID (Optional)
Description
Write Graphics Content
Write Graphics
End
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