Driver features

Driver features are non-PPD features that are synthesized by the driver (for example, the %OutputFormat feature). To avoid name conflicts with PPD feature keywords, all driver feature keyword names are preceded by a "%" character. Driver feature/option keywords are also case sensitive.

To obtain a list of all driver feature keywords that the driver supports, a plug-in can call EnumFeatures, which will return the feature keyword list containing both driver features and PPD features. The plug-in can then search for feature keyword names that begin with the "%" prefix to get the driver feature list.

The following table lists the currently supported driver features. Each row in the table lists a driver feature keyword, shows the supported options, states whether the feature's options can be enumerated in a call to EnumOptions, and provides a brief description.

Notes on Driver Feature Keywords

1. The %CustomPageSize driver feature has five option values: x, y, WidthOffset, HeightOffset, and FeedDirection. Please refer to section 5.16 of the PostScript Printer Description File Format Specification, Version 4.3, for a detailed explanation of these parameters.

   A %CustomPageSize entry contains the %CustomPageSize keyword, together with values for the x, y, WidthOffset, HeightOffset, and FeedDirection options. The first item is the %CustomPageSize keyword, followed by a NULL character. The values for x, y, WidthOffset, and HeightOffset follow this keyword, and appear as substrings of unsigned decimal digits, each representing the number of PostScript points for the corresponding option value. Each of these numeric values is followed by one or more space or tab characters. The final item in the string is the value for FeedDirection, which is terminated by a NULL character. The options for FeedDirection are "LongEdge", "ShortEdge" (corresponding to orientations 0 and 1), and "LongEdgeFlip", "ShortEdgeFlip" (corresponding to orientations 2 and 3). Check the *LeadingEdge PPD feature keyword for supported feed directions.

   For GetOptions, the output buffer pointed to by pmszFeatureOptionBuf is as described in the previous paragraph. In the following example, the value for x is 612, the value for y is 792, the values for WidthOffset and HeightOffset are both 0, and the value for FeedDirection is "ShortEdge".

   "%CustomPageSize\0612 792 0 0 ShortEdge\0"
   

   For SetOptions, extra tab or space characters before or after the decimal digits are allowed, but a sign symbol isn't allowed. Otherwise, the input buffer pointed to by pmszFeatureOptionBuf should be constructed as described above.

2. The %CustomPageSize driver feature is supported only if all three of the following conditions are met:

   1. The PPD file contains the *CustomPageSize feature.

   2. The *PPD-Adobe keyword has a value greater than or equal to 4.3, or *UseHWMargin: False is specified to indicate a roll-fed device.

   3. The *PageSize PPD feature's currently selected option is CustomPageSize.

3. This feature is supported only when spooler EMF spooling is enabled.

   When supported, setting this feature's option to "False" causes changes to the following EMF-related features:

   1. If %PagePerSheet is "Booklet", it's changed to "1".

   2. If Collate is set to "True" (which can be set either directly in the public portion of the DEVMODEW structure or by calling SetOptions on the *Collate PPD feature), but the Collate feature isn't currently available, Collate will be set to "False".

   3. If %PageOrder is the opposite of the printer's current output order setting, %PageOrder is reversed to the printer's value.

4. This feature is supported only when spooler EMF spooling is enabled.

   When it's supported, setting this feature can cause the following to occur:

   1. If the printer's PPD file includes the *OutputOrder feature keyword, then its option selection is changed to match the output order of the new setting for the %PageOrder feature. This is done to prevent the spooler from performing unnecessary page order simulation.

   2. If the printer's PPD file doesn't include the *OutputOrder feature, and the new setting for the %PageOrder driver feature is the opposite of the printer's current output order setting, and the %MetafileSpooling driver feature is "False", then %MetafileSpooling is reset to "True".

5. The "Booklet" option is supported only when spooler EMF spooling is enabled and the Duplex feature is available.

   When the "Booklet" option is supported, setting the %PagePerSheet driver feature to "Booklet" can cause the following changes:

   1. If the %MetafileSpooling driver feature is "False", it's reset to "True".

   2. If the *Duplex PPD feature is set to None, the *Duplex feature is reset to the first non-Simplex option defined in the PPD file.

6. Except for "EPS" (Encapsulated PostScript), the formats specified in the %OutputFormat driver feature are categorized according to the following two characteristics:

   1. Is the output PostScript code independent of page order?

   2. Does the output PostScript code contain device control commands (which usually use the setpagedevice operator)?

      Category	Page Order Independent	setpagedevice
      Archive	Yes	No
      Portability	Yes	Yes
      Speed	No	Yes

When GetOptions is called on driver feature keywords, if a requested feature keyword isn't recognized, or if the feature keyword is recognized but not supported in the current document-sticky or printer-sticky mode (see Replacing Driver-Supplied Property Sheet Pages), the feature will simply be ignored and the output buffer won't contain its feature/option keyword pair.

For example, suppose the GetOptions method is called, and the pmszFeaturesRequested input buffer contains the following string (in MULTI_SZ format):

"Resolution\0%CustomPageSize\0Unknown_Name\0%Orientation\0\0"

After GetOption returns, the pmszFeatureOptionBuf output buffer could contain this string (also in MULTI_SZ format):

"Resolution\0300dpi\0%CustomPageSize\0612 792 0 0 ShortEdge\0%Orientation\0RotatedLandscape\0\0"

Notice that the Unknown_Name feature (which doesn't exist) listed in the first string doesn't appear in the second string, since it wasn't recognized by the Pscript driver. The other features, Resolution, %CustomPageSize, and %Orientation, appear in the output string, together with their current options, which are "300dpi", "612 792 0 0 ShortEdge", and "RotatedLandscape", respectively. See Driver Features for an explanation of the %CustomPageSize options.

When SetOptions is called on driver feature keywords, if a requested feature keyword or its option keyword in the input buffer pointed to by pmszFeatureOptionBuf is not recognized, or the feature is recognized but not supported in the current document-sticky or printer-sticky mode (see Replacing Driver-Supplied Property Sheet Pages), or both the feature keyword and its option keyword are recognized but the option keyword is invalid for that feature (for example, trying to set %TTDownloadFormat to "NativeTrueType" on a printer that does not support Type42 TTRasterizer), then that feature/option pair will be ignored and the current option for that feature will continue to be in effect.

The order of feature/option keyword pairs in the buffer pointed to by pmszFeatureOptionBuf can affect the result of the SetOptions call. For example, the following two different orders have different results.

For an explanation of why these results occur, see Note 3 on %MetafileSpooling, above.