Compuprint 4247-Z03 Programmer Manual - Manual (Page 115)

WT (Write Text): The WT command sends text data to the printer. Because the printer is currently in a
page segment state, this text information does not print at this time. Instead, the data becomes part of the
page segment. The host can send multiple WT commands to the printer while in the page segment state.
WIC (Write Image Control): The WIC command causes the printer to enter the image block state.
Parameters in this command define the image size, scale, initial coordinates, and color of the image.
WI (Write Image): The WI command sends a block of image data to the printer. One or more of these
commands create the actual image for later printing.
END (End): The END command terminates the image block state. The printer remains in the page
segment state with the image stored for later use.
WT (Write Text): This command is repeated at this point in the sequence to illustrate that additional text
data can be added to the page segment. In addition to zero or more of the WT commands, this segment
could also include additional graphics data, image data, or bar code data.
EP (End Page): The EP command causes the printer to leave the page segment state and return to the
home state. We recommend that this command contain an acknowledgment request to let you know of
successful execution of the page segment.
ACK (Acknowledgment Reply): If the previous command had the ARQ bit on, the printer responds with
the ACK command to inform the host of successful execution of all the previous commands. This
command indicates to the host that the printer has accepted all the segment data and stored this
information for later printing.
Overlay Sequence
The overlay sequence creates one or more overlays for later printing. The following command sequence
illustrates the loading of a typical overlay:
v
BO (Begin Overlay)
v WT (Write Text)
v IO (Include Overlay)
v WGC (Write Graphics Control)
v WG (Write Graphics)
v END (End)
v WT (Write Text)
v IO (Include Overlay)
v IPS (Include Page Segment)
v EP (End Page)
v ACK (Acknowledgment Reply).
Note: This sequence is only an example. An overlay can contain any combination of text, image blocks,
graphics blocks, bar code blocks, page segments, or overlays.
BO (Begin Overlay): The host sends the BO command to the printer causing the printer to leave the
home state and enter the overlay state. The overlay state creates an overlay of data to save within the
printer for later printing. The BO command contains an identifier (ID) for later use in selecting this overlay.
WT (Write Text): The WT command sends text data to the printer. Because the printer is currently in an
overlay state, this information does not print at this time. Instead, the data becomes part of the overlay.
The host can send multiple WT commands to the printer while in the overlay state.
IO (Include Overlay): The IO command causes a previously stored overlay to merge onto the current
overlay. This command contains an ID field that selects the desired overlay.
Chapter 3. Intelligent Printer Data Stream 95