TweetFollow Us on Twitter

Customizing Desktop Printer Util

Volume Number: 13 (1997)
Issue Number: 11
Column Tag: develop

Customizing Desktop Printer Utility

by Brendan Galten and Ingrid Kelly, Apple Computer, Inc.

In the current LaserWriter 8 driver, the Chooser lists printers which are available on the AppleTalk network (either LocalTalk or AppleTalk) with an NBP type of "LaserWriter." When the user selects one of these printers, LaserWriter 8 creates a desktop printer by sending an Apple Event to the Finder. In the past, this mechanism of setting up printers has served the needs of most users. However, with LaserWriter 8.5.1, Apple is responding to several requests for more flexible desktop printing functionality. To this end, Apple has introduced a new application called Desktop Printer Utility which enables users to create additional types of desktop printers. Users can now create desktop printers which use the Unix lpr protocol for printing, in addition to the regular AppleTalk PAP printers. There are also "hold" printers which represent local print queues and "virtual" printers which represent printers which are not available on the network.

Along with the expanded capabilities, Desktop Printer Utility is also customizable. LaserWriter 8.5.1 and Desktop Printer Utility (together) support the creation and use of desktop printers known as Custom DTPs. When printed to, Custom DTPs cause the LaserWriter 8.5.1 driver to create a PostScript file and to launch an application that can post-process the PostScript. This post-processing application can do anything it likes with the PostScript file, such as converting the PostScript into another file format, transferring the file to another location using a modem or a network connection, or displaying the PostScript file to the user. This article describes how a developer might customize Desktop Printer Utility for use with an application.

Customizing the DTP Utility

In order to add a new custom DTP to the list of supported DTPs in Desktop Printer Utility, you must add resources to the utility's resource fork. Desktop Printer Utility contains templates to ease the creation of these resources.

'CsDs'(CustomDTPResource) Resource

In order to customize Desktop Printer Utility, a 'CsDs' (CustomDTPResource) resource must be added to Desktop Printer Utility. The LaserWriter uses this information to find the appropriate application to launch and to customize your DTP interface.

The resource's format is defined by the structure 'CustomAppDesc:'

#define kVariableLen 1

struct CustomAppDesc{
    OSType appSignature;    
    Str255 docType;    
    Str255 helpText;    
    Str255 usage;      
    Str255 appFileName;     
    short numOfHintsFollow;  
    HintRsrcSpec hintRsrc[kVariableLen];  
typedef struct CustomAppDesc CustomAppDesc;
  • appSignature: The application signature of the application to launch. The LaserWriter driver uses this information to find the application on all mounted volumes which are available to the user.
  • docType: A string that describes the type of custom DTP. This string appears in the list of document types when "New" menu is selected. This string is highlighted in Figure 1.
  • helpText: This string appears when your custom DTP is selected. This string will appear in the "New" dialog field just below the DTP choices. This string appears as 'Custom DTP Example Help Text' in Figure 1.
  • usage: A string that describes the usage of your custom DTP. This string appears as 'Custom DTP Example Usage string' in Figure 2.
  • appFileName: The name of the application to launch. The LaserWriter driver uses this information to find the application on disks which are available to the user as well as to provide error messages to the user (e.g. "SurfWriter could not be launched due to insufficient memory").
  • numOfHintsFollow: The number of hints provided in the hintRsrc array. See the 'Hints Resources' section for more details.
  • hintRsrc: An array of hints that outlines the kind of PostScript that should be generated by the driver. See the 'Hints Resources' section for more details.

Figure 1.

Figure 2.

Hints Resources (optional)

The CustomDTPResource can provide 'hints' about the PostScript the driver should generate. Each 'CustomDTPResource' contains the field 'numOfHintsFollow' which represents the number of 'hints' provided. The 'hints' data is placed in an array that contains 'numOfHintsFollow' number of copies of the structure:

  struct HintRsrcSpec{
    OSType rsrcType;    
    short rsrcID
  typedef struct HintRsrcSpec HintRsrcSpec;

Each entry in the array points to a resource which is converted to a hint in the driver's preferences. The hint resource types, which are currently supported, have the following formats:

/* PostScript Level */

The application that postprocesses the PostScript for a custom DTP may require or prefer a certain PostScript level. The 'pslv' hint specifies the desired PostScript level.

Resource type 'PSlv' 
typedef struct{
    OSType hintType;      //'pslv' hint type
    long hintId;        // set to 1
    long psLevel;

#define kHintLanguageLevelTag  'pslv'
#define kHintLanguageLevelId  1

The possible(current) values for psLevel which can be set are:

  -3,  Level 2 and 3 
  -2,  Level 1 and 2 
  -1,  Unknown Level 
   0,  Other Level     //do not use
   1,  Level 1 
   2,  Level 2 
   3   Level 3

Note: -3 will create PostScript that takes advantage of PostScript level 2 and level 3 printers, but the data may fail on a level 1 printer. -2 will create PostScript that will succeed on level 1, 2, and 3 printers.

/* Binary OK - 'bnok' */

This hint allows or disallows the use of binary data in the PostScript file.

Resource type 'BNok' 
typedef struct{
    OSType hintType;    //'bnok' hint type
    long hintId;        // set to 1
    TriState binaryOK;      

#define kHintADOIsBinaryOKTag  'bnok'
#define kHintADOIsBinaryOKId  1

There are three acceptable settings for binaryOK which answer the question, "Is binary data ok?":

   0,    False
   1,    True
   2     Unknown     //do not use

Note: This hint should not be created in the DTP with a value of unknown; however, it is available for future use.

/* Job Type - 'jobt' */

This hint specifies the type of PostScript to generate.

Resource type 'JObt' 
typedef struct{
    OSType hintType;    //'jobt' hint type
    long hintId;        // set to 1
    char jobType;      

#define kHintJobTypeTag   'jobt'
#define kHintJobTypeId    1

Currently only two PostScript forms for jobType are available:

    0,  psJobPostScript 
    1   psJobEPSNoPreview

/* Font Handling - 'font' */

This hint specifies the font inclusion. The font handling hint consists of a four-byte flag followed by a list of NULL terminated font names.

Resource type 'FOnt'
typedef struct{
    OSType hintType;      //'font' hint type
    long hintId;          //set to 1
    long tag;    
    unsigned char name[1];  

#define kHintIncludeFontsTag    'font'
#define kHintIncludeFontsId      1

The possible values for tag are:

    0,  kIncludeNoFontsOtherThan
    1   kIncludeAllFontsBut

If the flag is 'kIncludeNoFontsOtherThan', the utility will only include the font definitions of fonts that are listed after the flag. If there are no font names after the flag, no font resources are included in the output. If the flag is 'kIncludeAllFontsBut', font resources are included in the output unless the font names are listed. To include all fonts, use the 'kIncludeAllFontsBut' flag with no fonts listed afterwards.

Sample Custom DTP

Following is a sample of a custom DTP that excludes Courier and Helvetica from the PostScript file via a 'CsDs' and 'FOnt' resource. This sample is intended to give developers an idea of how easy it is to customize the DTP Utility. The first step towards adding the Custom DTP is to create a hint resource of the correct type. The example shown is the 'FOnt' resource which provides data about font inclusion.

Figure 3.

The second step is to associate the hint with a particular DTP by adding hint resource information to the 'CsDs' resource for a particular DTP.

Figure 4.

And that's all that is required to get the DTP Utility to create a custom DTP that produces a PostScript file without Courier and Helvetica.

Limitations of the DTP Utility

Due to the parallel development schedules of Mac OS 8.0 and LaserWriter 8.5.1, DTP Utility 1.0 (which ships with LaserWriter 8.5.1) will not install on Mac OS 8.0. It will, however, work with Mac OS 8.1, due out in Fall of 1997.

Licensing the DTP Utility

In order to ship a customized DTP Utility with your application, you must license the DTP Utility from Apple. Please contact Apple's Software Licensing group ( or 512-919-2645) for more information.


This article has described and demonstrated all that is necessary for you to customize Desktop Printer Utility. We encourage all developers to give this a try.

Further References

  • 'Introducing the LaserWriter Driver Version 8.5.1' by Ingrid Kelly in this issue of MacTech.


Thanks to Leticia Alarcon, John Blanchard, Richard Blanchard, Paul Danbold and David Gelphman.

Brendan Galten is a software engineer with RBI Software Systems in Berkeley, Ca. He resides in Petaluma, Ca. When not writing software, he enjoys spending time with his beautiful wife, Rosemary, and making sure his 9 month old daughter, Kelly, doesn't eat bugs. Camping, fishing and woodworking occupy what little time is left.

Ingrid Kelly is a technical support engineer at Apple Computer. She and her husband, Lance, are constantly in search of the best new restaurants in the San Francisco Bay Area. One day, they may decide to leave the computer industry altogether and open one of these great restaurants themselves. For now, though, they are content helping Silicon Valley grow.


Community Search:
MacTech Search:

Software Updates via MacUpdate

The best games like Animal Crossing on m...
Animal Crossing amiibo Festival is out right now for the Wii U, reminding us of just how much fun that world can be. Or at least to go back and check in on our villages once in a while. [Read more] | Read more »
Between 2 Taps - Tap for Tap interview M...
Hello, and welcome back to Between 2 Taps, Tap for Tap’s Indie Dev interview series. [Read more] | Read more »
Facility 47 (Games)
Facility 47 1.0.1 Device: iOS Universal Category: Games Price: $3.99, Version: 1.0.1 (iTunes) Description: You wake up alone and freezing in an icy cell. You try the cell door but it’s locked, it seems that you are stuck with no... | Read more »
The best Photoshop alternative on iPad
Instagram and Lightroom are great and all, but sometimes people need to get extra creative with their image editing.Like, Photoshop creative. If you're one of these people, take a look at our pick for the best mobile Photoshop experience on iPad... | Read more »
The Walking Dead: No Man’s Land guide -...
A new update for The Walking Dead: No Man’s Land was released last week, making it the perfect time for you to head back to your base and take out some walkers. Here’s the lowdown on what’s new to the game, and how to take advantage. [Read more] | Read more »
Goat Rider guide - Tips and tricks to st...
We've all been there. One second, we're riding high on a crazed goat, and the next, we've been tossed off it like someone who's no good at goat ridin'. [Read more] | Read more »
Real Boxing 2 CREED: How to become a gre...
Just in time for Rocky fans who can’t wait to see CREED, the latest movie, we have the official tie-in game,Real Boxing 2 CREED. It builds on the success of its predecessor and there’s lots to take in so we at 148apps thought we’d run you through... | Read more »
CoinOp Heroes 2 guide - How to build an...
CoinOp Heroes 2 justlaunched and, like all clickers, it's dangerously addictive stuff. You have to furiously tap your screen to defeat wave after wave of foes and earn an insane amount of cash to spend on character upgrades and an army of minions... | Read more »
Dr. Panda Firefighters (Education)
Dr. Panda Firefighters 1.0.1 Device: iOS Universal Category: Education Price: $2.99, Version: 1.0.1 (iTunes) Description: FIGHT FIRES AND SAVE THE DAY!Work together with Dr. Panda and his firefighting team to rescue his trapped... | Read more »
Puddle + (Games)
Puddle + 1.0 Device: iOS iPhone Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: Puddle is back in a new "+" edition featuring enhanced graphics, new videos and Apple TV support ! No IAP and No Ads. Dive into Puddle... | Read more »

Price Scanner via

Save $30-$40 on new Apple TVs after rebate
Adorama has new Apple TVs on sale for up to $40 off MSRP after mail-in rebate, good through December 15th. Shipping is free, and Adorama charges NY & NJ sales tax only: - 32GB Apple TV: $119.99... Read more
13-Inch Haswell MacBook Air At Two Years – Th...
The 13-inch mid-2013 “Haswell” MacBook Air I ordered in Apple’s November 2013 Black Friday sale was my first new Mac in four and a half years — the longest interval I’ve gone between system upgrades... Read more
Target Black Friday Early Access deals: $100...
Target is offering early access to their Black Friday deals on Apple products on their online store for today, the 25th, only. Choose free shipping or free local store pickup (if available): - Apple... Read more
BlackBerry Q3 Mobility Index Report Finds iOS...
BlackBerry has announced results of its thirteenth Good Mobility Index Report, showing that organizations are increasingly building custom secure apps. Among Good Powered by BlackBerry (formerly Good... Read more
Wednesday roundup of early Black Friday Mac s...
Save up to $500 on a new Mac with these early Black Friday deals from Apple resellers, currently the lowest prices available for these models: (1) B&H Photo has all new Macs on sale for up to $... Read more
iPod nano on sale for $119, $30 off MSRP
Walmart has the 16GB iPod nano (various colors) on sale for $119.20 on their online store for a limited time. That’s $30 off MSRP. Choose free shipping or free local store pickup (if available). Sale... Read more
Adorama Black Friday deals: Up to $400 off Ma...
Adorama has released their Black Friday deals for 2015. Save up to $400 on MacBook Pros, $200 on MacBooks and MacBook Airs, and $270 on iMacs. Use code RYBFDEAL during checkout to see these prices.... Read more
B&H Photo Deals: $200 off 12-inch 1.2GHz...
In addition to the B&H Photo Black Friday week sales we posted yesterday, B&H has lowered their price on two products to $200 off MSRP: - 12″ 1.2GHz Gray Retina MacBook: $1399 save $200 - 13... Read more
Best Buy Early Access: Today only, Up to $125...
Best Buy has iPad Air 2s on sale for up to $125 off MSRP and Apple Watch models on sale on their online store for up to $100 off MSRP with special codes through midnight CT tonight. Choose free... Read more
UPPERCASE DESIGNS Premium Ultra Thin Keyboard...
UPPERCASE Designs today announced its new Premium Ultra Thin Keyboard Protector and its Palm Rest Protector Set for the 12-inch MacBook. The accessories provide durable protection for the 12-inch... Read more

Jobs Board

Hardware Systems Integration Engineer - *App...
# Hardware Systems Integration Engineer - Apple Watch Job Number: 39380139 Santa Clara Valley, Califo ia, United States Posted: Apr. 23, 2015 Weekly Hours: **Job Read more
Sr. Technical/Project Manager, *Apple* Educ...
# Sr. Technical/Project Manager, Apple Education Job Number: 36588557 New York City, New York, United States Posted: Jul. 30, 2015 Weekly Hours: 40.00 **Job Summary** Read more
*Apple* Retail - Multiple Positions (US) - A...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
Merchant Operations Manager: *Apple* Pay -...
Changing the world is all in a day's work at Apple . If you love innovation, here's your chance to make a career of it. You'll work hard. But the job comes with more than Read more
*Apple* Pay QA Manager - Apple Inc. (United...
Changing the world is all in a day's work at Apple . If you love innovation, here's your chance to make a career of it. You'll work hard. But the job comes with more than Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.