Installing PPD Files

Unlike earlier versions of the Mac OS, OS X requires you to install the PPD files for a printer in localized folders. You must install a PPD file in the en.lproj folder, as the printing system uses the PPD files in this folder to determine which printers are supported.

Apple recommends you provide localized PPD files according to the following priority groups:

• Required: English

• Priority 1: French, German, and Japanese

• Priority 2: Dutch, Italian, and Spanish

• Priority 3: Brazilian Portuguese, Simplified Chinese, Korean, Traditional Chinese, Danish, Finnish, Norwegian, and Swedish

A localized PPD file should be installed into the folder appropriate for the language of the localized file. The naming convention for localized folders is the same as that used for localized bundle resources in OS X. Folders are named with an ISO 639 language code and an .lproj suffix. For example, PPD files localized for English and Korean should be in folders named en.lproj and ko.lproj. Table 3-1 lists the ISO 639 codes for the Apple-recommended languages. You can find a complete list of ISO 639 country codes at this website:

http://etext.lib.virginia.edu/tei/iso639.html

If you provide a PPD file for a local variation of a language, such as Canadian French or Swiss German, you can use the ISO 3166 codes, as the ISO 639 codes do not differentiate between local variants.

Installation Path

PPD files for all printer manufacturers should be installed in the following location, in the appropriate localized folders:

• /Library/Printers/PPDs/Contents/Resources/

Each PPD file should have its privileges set to Read Only for Owner, Group, and Everyone.

All localized third-party PPD files, regardless of printer manufacturer, must be installed in the same localized folder, as shown in Figure 3-1. When you install a localized PPD file, you should first check to see if the appropriate language folder exists. If it does not, you must create the folder in this directory:

• /Library/Printers/PPDs/Contents/Resources/

When OS X searches for a PPD file, it looks in the locations specified in How OS X Searches for and Chooses PPD Files. If there is more than one localized PPD file installed for a printer, OS X chooses one, and it does so without user interaction.

Creating a Localized PPD File

There are two things you need to do to create a localized version of a PPD file:

• specify the character encoding and language

• translate strings that are displayed in the user interface

One value you do not need to localize is *DefaultPageSize, as OS X does not use this value. The printing system sets a default paper size across a user’s set of printers, rather than on a printer by printer basis.

*LanguageEncoding: ISOLatin1// 1

*OpenUI *TraySwitch/Zufuhrumschaltung:  Boolean// 2

*OrderDependency: 20 AnySetup *TraySwitch

*DefaultTraySwitch: False// 3

*TraySwitch True/Ein: "1 dict dup /TraySwitch true put setpagedevice"// 4

*TraySwitch False/Aus: "1 dict dup /TraySwitch false put setpagedevice"// 5

*?TraySwitch: "// 6

   save

   currentpagedevice /TraySwitch get

   {(True)}{(False)}ifelse = flush

   restore

"

*End

*CloseUI: *TraySwitch

Specifying Grouping in the Printer Features Pane

In OS X version 10.1 and later, printer vendors can use grouping keywords in a PPD file to specify how features should be grouped in the Printer Features pane. As described in The Printer Features Pane in the Print Dialog, the features you can group are limited to Boolean items and lists in which only one option can be selected at time. This section shows you how to specify a group that has two features: a pop-up menu (PickOne) for Fold Type and a checkbox Boolean for Banner Sheet.

Listing 3-2 is an excerpt from a PPD file. Note that some of the lines in the listing are numbered. An explanation for each numbered line follows the listing.

Listing 2-2  Specifying a group of Finishing features in a PPD file

*OpenGroup: Finishing/Finishing Options// 1

*OpenUI *FoldType/Fold Type: PickOne// 2

*DefaultFoldType: None// 3

*FoldType Fan/Fan: "% postscript code to invoke Fan fold "// 4

*FoldType Saddle/Saddle: "% postscript code to invoke Saddle fold "

*FoldType Wing/Wing: "% postscript code to invoke Wing fold "

*FoldType None/None: "% postscript code to invoke no fold "

*CloseUI: *FoldType// 5

*OpenUI *BannerSheet/Banner Sheet: Boolean// 6

*DefaultBannerSheet False: // 7

*BannerSheet True/True: "% postscript code to invoke a banner sheet "// 8

*BannerSheet False/False: "% postscript code to turn off a banner sheet "

*CloseUI: *BannerSheet// 9

*CloseGroup: Finishing// 10

Here are the explanations for the numbered lines in Listing 3-2:

1. When you define a group, the *OpenGroup keyword must be at the start of the group of features. The translation string value Finishing Options is the group’s name. This appears as the tab name in the Printer Features pane.

2. The *OpenUI keyword must be at the start of any feature that appears in the user interface. The option *FoldType is the feature name. The string value after the slash (/)—Fold Type —is the translation string; it’s the text label that appears for that feature in the user interface. The option PickOne specifies a list of options from which only one can be selected. It is represented as a pop-up menu in the user interface.

3. The keyword *DefaultFoldType specifies the required default value, which in this case is the string value None. This is the option that’s selected when the user opens the Printer Features panel.

4. This line, and the other lines that begin with the keyword *FoldType, specifies an option that appears in the Fold Type pop-up menu. *FoldType must be followed by a string value; in this case, it is Fan. The translation string—Fan—appears after the slash. The translation string must be followed by the PostScript code that invokes this feature in the printer.

5. The *CloseUI keyword must be at the end of any feature that’s defined with the *OpenUI keyword. It must be followed by the main keyword for the feature name.

6. This line defines a Boolean feature. *BannerSheet is the feature name and the translation string Banner Sheet is the text label that appears in the user interface.

7. The keyword *DefaultBannerSheet specifies the required default value, which in this case is the Boolean value False.

8. This line and the next are very important for a Boolean feature. A Boolean feature must define two, and only two options. One must provide the value True, and the other must provide the value False. Each option must supply the PostScript code to invoke the feature associated with the option in the printer.

9. The *OpenUI keyword must be paired with *CloseUI keyword. Don’t forget to supply the main keyword for the feature name.

10. The keyword *CloseGroup specifies the end of a group. The string value Finishing indicates it is the end of the Finishing features.

The PostScript Printer Description File Format Specification document contains additional details on the syntax needed to specify groups and options, as well as information on adding code that’s invoked when an option is selected.

Adding PPD Keywords to a PDE’s Information Property List

A printing dialog extension (PDE) is a powerful and flexible way to extend the Print dialog in OS X. It lets you use any of the system services to draw, animate, or otherwise render a pane in the Print dialog to create a custom user interface for specific features. You can find details for writing a PDE in Inside OS X: Extending Printing Dialogs. The purpose of this section is to show you how to register PPD keywords that are supported by your custom printing dialog extension. If you don’t register the PPD keywords, the features associated with the keywords appear in the Printer Features pane.

You add the supported PPD keywords to the PDE’s information property list in Project Builder, when you are writing the PDE. When the finished PDE is loaded for a specific printer, the OS X printing system (specifically, the Printer Features printing dialog extension provided by Apple) checks the information property list. Features corresponding to PPD keywords that are included in the information property list are not displayed in the Printer Features panes. Instead, the features on the PDE’s property list are displayed in the pane created by your PDE.

You should make sure keywords are unique with respect to the printer. Conflicts between PDEs that support the same keyword are not detected by the printing system. You should also make sure your PDE loads only for the specific printer for which it is intended. If every PDE loads only for the proper printer then there won’t be multiple PDEs trying to handle the same feature for a given printer.

Figure 3-2 shows an information property list as it appears in Property List Editor. It is a property list for a PDE that supports two paper feed options for a PostScript printer—input slot and manual feed. The property PMPPDKeysSupported is an array with two string values, InputSlot and ManualFeed. The PPD for the printer should contain the media selection keywords *InputSlot and *ManualFeed.

To add PPD keywords to the property list for a PDE, do the following:

1. Open the PDE project in Project Builder.

2. Click the name of the PDE target in the Targets list, then click the Bundle Settings tab.

3. Click the Expert button, then click New Sibling.

4. Type PMPPDKeysSupported in the Property List column.

   The search for this keyword is case–sensitive, so make sure the case is correct.

5. Choose Array from the Class pop-up menu.

6. Click the disclosure triangle next to PMPPDKeysSupported, then click the New Child button.

   When you click the disclosure triangle, the New Sibling button changes to New Child.

7. Double-click the text box in the Value column, type the PPD keyword, then make sure its Class is set to String.

   For example, if the PPD keyword is *InputSlot, type InputSlot.

8. For each additional PPD keyword, add another child to the PMPPDKeysSupported property, then repeat Step 7.

Changing PPD and PDE File Binding

A PPD file and printing dialog extension for a printer are bound to a printer queue when the queue is created. When the operating system determines the language and encoding of the PPD file, it parses the file, and then saves the PPD for use by the printing system. If the PPD file is changed after the printer queue is created, the changes in the PPD file are not reflected in the Print dialog unless the user deletes and then recreates the printer queue.

Similarly, if the user changes the preferred language, the change is not reflected in the Print dialog associated with a printer queue that’s already setup. The user must delete and recreate the printer queue for the language change to take effect.