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Note: Adobe Systems, Inc. imposes strict limitations on the use of the Configurable PostScript Interpreter by developers. Please refer to Appendix H, “Using the Adobe Configurable PostScript Interpreter,” for details.

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The PostScript interpreter, psrip, has been upgraded to an Adobe Level II Configurable PostScript Interpreter (CPSI). ^[3] Two significant improvements are its ability to set the gamma correction for individual color channels, and its ability to invoke psrip as a band device as well as a frame device. (You can also let it choose between them.) A band device renders the output raster image as a series of sequential bands rather than as a complete entity. It thus usually requires much less memory than a frame device. (A minimum band size of 5 megabytes is recommended.) See the psrip(1) reference pages for all the new features.

psrip is the only executable in Impressario 2.n that is licensed. It uses a FLEXlm node-locked license, stored in the file /var/flexlm/license.dat, and returns an error if the license is not available. You can use the License Manager in the System toolchest menu to update software licenses. For more information on obtaining a license, see the file /usr/lib/print/data/psrip_expired_msg. Additional information on FLEXlm can be found in the online manuals FLEXlm End User Manual and FLEXlm Programming Guide.

psrip always runs as set user ID lp to guarantee that its files have the same ownership.This is necessary because psrip creates temporary and permanent files in /var/spool/lp/psparams and needs to be able to modify them.

Halftone screens are found in /usr/lib/print/data/screens. Three screens are available:

The psrip -I option can be used to select between these screens. See the model file /usr/impressario/src/models/laserjetPJL_model for examples.

Fonts are in the directory/usr/lib/DPS. psrip uses the /usr/lib/DPS/AdobeFonts.upr file to determine the available fonts. The makepsres(1) function, which is automatically run (as an exitop) when the user quits the Software Manager after installing the dps_eoe.sw.dps sub-system, builds /usr/lib/DPS/AdobeFonts.upr based on the installed fonts.

The directory /usr/lib/print/data/psrip contains other resources used by psrip including Color Rendering Dictionaries (CRDs) and the default startup.ps file.

There are some other changes in psrip:

For Impressario 2.n, there is an updated sample model file for HP LaserJet printers, /usr/impressario/src/models/laserjetPJL_model. The Impressario 1.2 version of the laserjet_model lp model file is still available for comparison and is found in the directory /usr/impressario/src/models. There are several major changes in the updated file:

Other changes of interest in Impressario 2.n are as follows:

Finally, releases of IRIX after version 6.2 will not support CTR (Compiled Type Rule) database files. Your model files may be checking for this file using code like this:

if [ ! -r /usr/lib/filetype/workspace.ctr ]; then
    disable -r”WorkSpace filetype database not built. Type `su; cd /usr/lib/filetype; make'” \
    $printer 1>>$logfile 2>&1
    exit 2
fi

You should remove or comment out the above block of code. Future versions of fileconvert will map the old filename, workspace.ctr, to the new name, desktop.otr, to maintain backward compatibility. Even so, the file /usr/lib/filetype/workspace.ctr may not exist, so you should still remove the above code.

Starting with Impressario 2.0, a new logical AND operator, &, is available for font lists. Now the list of fonts on the printer can be logically AND'ed with the list of fonts on the print server, generating a list of common fonts that the graphical options panel can present to the user. The common list is important because the text2ps filter uses the font metric information of the print server fonts to determine where line breaks and page breaks should be made. The AND operator is intended for printer drivers that send PostScript directly to the printer. See Appendix C, “Printer Object Database (POD) File Formats,” for an example.

Some changes that affect printer drivers are

Another change may be necessary for drivers using nethandler. To avoid network printer timeouts, printer drivers that are meant to be used with nethandler should not send data to standard output until they read something from standard input. By waiting, the drivers can avoid initializing the printer prematurely because nethandler won't open a socket connection to the printer until it receives data from the driver via standard input.

Here is the underlying problem. When the printer driver is invoked from a model file,

image2ps image_file | psrip | printer_driver | nethandler

a delay is introduced as the programs upstream from the printer driver process the data. If the image being processed is complex, the printer driver may not see data on standard input for some time. If the printer driver sends initialization commands to the printer immediately, nethandler will open a socket connection to the printer to deliver them. Most network printers then start a timeout sequence and close the socket if they do not see any more data before the timeout expires (typically 90 seconds to 2 minutes). If the processing upstream from the printer driver takes longer than the timeout period, the socket connection will be closed by the printer and nethandler will return an error. Recovery from this is difficult because trying again will probably have the same result.

Current printer drivers probably perform this sequence of events (which risks a timeout):

parse command line
send commands to printer to initialize it
while (data to read from standard input) do
read data from input
process data and format for printer
output data to printer 
done
cleanup

The timeout problem can be addressed by modifying the printer drivers so:

parse command line
while (data to read from standard input) do
read data from input
process data and format for printer
(if never initialized) send commands to printer to initialize it
output data to printer
done
cleanup

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Tip: When a print client is configured, it copies the Graphical Printer Options Panel executable from the print server to /var/spool/lp/gui_interface/ELF. By default, IRIX 6.2 generates o32 MIPS2 ELF binaries. MIPS2 executables will not run on IRIX 5.3 systems with a MIPS R3000 processor, the configuration of many Indigo workstations. (IRIX 6.2 is not supported on R3000 systems.) Compile the Graphical Printer Options Panel under IRIX 5.3 if you wish to support IRIX 5.3 systems running on a R3000. The subsystem impr_dev.sw5_3 contains all of the Impressario 2.0 libraries compiled under IRIX 5.3. The libraries are installed in /usr/impressario/53libs and can be copied to your 5.3 development system.

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All of the Graphical Printer Options Panel executables supplied in Impressario 2.0 were compiled and linked under IRIX 5.3.

The Graphical Printer Options Panel now has a context-sensitive help panel at the top of the window. This gives a short description of any option pointed to with the mouse. See the sample source code in /usr/impressario/src/gui_models/laserjetPJL.