Dynamic Download of Image Decompression Code to a Non-Programmable Terminal
Original Publication Date: 1995-Jan-01
Included in the Prior Art Database: 2005-Mar-29
Amell, SJ: AUTHOR [+6]
Disclosed is a method for image or fax decompression code to be dynamically downloaded into a non-programmable terminal, either solicited or unsolicited, with very limited host support.
Dynamic Download of Image Decompression Code to a
a method for image or fax decompression code to be
dynamically downloaded into a non-programmable terminal, either
solicited or unsolicited, with very limited host support.
Non-Programmable Terminal (NPT) provides the ability to
display monochrome image/fax on the display screen. The NPT may
support common monochrome image/fax formats. The image/fax NPT is
supported as follows:
1. A host application desires image or fax data to be added to the
NPT display screen; the user probably selected an image or fax
to view. The application calls a host-provided viewer program
running on the host. The calling application passes the
of the image or fax within the host, information on the user
interface desired, and the local functions which should be
available to the user (scaling, scrolling, rotating).
2. The viewer program builds the appropriate display data stream
download the image/fax to the NPT, with the appropriate user
interface, and local user controls.
3. The Work Station Controller (WSC) does limited processing of
image/fax data; the WSC sends the data to the NPT.
4. The NPT receives the image/fax data, decompresses, and scales
data into the desired location/size on the NPT display screen.
5. The user can scroll the image/fax data locally in the NPT. The
user can scale and rotate the data by interacting with viewer
program created controls. These user events go back through
WSC to the viewer program, which specifies the change in
image/fax presentation via a display data stream which is
through the WSC to the NPT.
6. When the user cancels viewing the image/fax, this user event go
back through the WSC and viewer program to the calling
The NPT could support dynamic download of additional
image or fax
decompression microcode beyond the common formats supported in the
1. Architect a flag in the image/fax display data stream which
indicates this is NPT "microcode" which can decompress a
image/fax format, instead of image/fax data.
2. Add a flag to the interface to the host-provided viewer program
which indicates this is NPT "decompression microcode" instead
3. Architect a new AID value (AID values are normally keys like
Enter, Help, and command keys), which indicates an unsupported
image/fax format was received in the NPT. Instead of the
cursor row and column values being returned to the application
with the AID, a two byte image/fax format value is returned: