External PostScript Printers - Printers and Fonts Kit(3.1)

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◄Up► ◄Next► ◄Previous► ──────────────────────────────────────────────────────────────────────────── In addition to supporting a wide variety of PostScript printers, the Microsoft Windows PostScript printer driver can also support any new PostScript printers for which the user installs an external printer definition. For the user to be able to do this, the printer manufacturer must supply a Windows Printer Description (WPD) file that contains information about the new printer. Printer manufacturers create the WPD files by compiling Adobe-standard PostScript Printer Description (PPD) files with the MKPRN utility. This topic describes how font manufacturers can build the WPD files and distribution disks that will enable users to add a printer to the Microsoft Windows PostScript printer driver. Building and Distributing WPD Files To build Windows Printer Description files, a font manufacturer must first build PPD files for each printer and PFM files for the each printer's resident font or soft fonts. The font manufacturer then uses the MKPRN utility to generate the WPD file. To distribute WPD files, a font manufacturer copies the WPD file to disk along with a OEMSETUP.INF file that describes the external printers the WPD file supports. Once a WPD file is installed, it defines the following features of the external printer: ♦ Resident fonts ♦ Paper sizes and input trays ♦ Commands that activate sizes and trays ♦ Imageable area of each supported page size (that is, the area on which the printer can actually mark) The following sections describe the formats of the various files. PostScript Printer Description Files The PostScript Printer Description file format, defined by Adobe and extended by the Microsoft, provides the basis for external printer descriptions. This ASCII file contains one or more statements, each consisting of a keyword and associated values. Each keyword defines a feature of the PostScript printer. The associated values specify whether the feature is available, or how the feature affects the operation of the printer. For example, the "*FileSystem" keyword specifies whether a printer supports fonts loaded on a hard drive. PPD files must be standard ASCII files with carriage return and line feed pairs terminating each line. To ensure the best performance for a printer, the PPD file should be as complete as possible. Windows 3.1 has defined new PPD keywords that should be added to existing PPD files to create new WPD files. If these keywords are not added, the driver can still use the old WPD files, but it will assign default values to any keywords not explicitly defined. The following provides descriptions of the PPD keywords. Keyword Description ──────────────────────────────────────────────────────────────────────────── *ColorDevice Indicates whether the printer supports color. *DefaultFont The name of the default font (that is, the font used if none is selected). This setting must appear before any "*Font" settings. *DefaultInputSlot The default input slot. *DefaultResolution The default resolution of the printer. *Duplex PostScript commands to set duplex mode. This feature is new for Windows 3.1. *FileSystem Reserved; do not use. *Font The fonts resident in the printer. *FreeVM Amount of free memory in standard printer configuration. This feature is new for Windows 3.1. *ImageableArea The actual area that can be marked on for every paper size. *InputSlot The PostScript code that is necessary to specify each input slot. *ManualFeed False The PostScript code that is necessary to turn off manual feed. If present, it is assumed that manual feed is supported. *ManualFeed True The PostScript code that is necessary to specify the manual feed operation. If present, it is assumed that manual feed is supported (and therefore PageRegion settings must be included). *NickName The name that appears in the printer dialog box. It should be a unique description of the printer. This is also the name used for automatic printer recognition. *PageRegion The PostScript code that is necessary to specify different page sizes when using manual feed. *PageSize The PostScript code used to specify the different page sizes that are supported (when not in manual-feed mode). *PaperDimension The size of all the used paper types. A Paper Dimension setting must be included for every size of paper supported. The sizes of the standard page types should be used. Only standard page types are recognized. *SetResolution Used to determine the hardware resolution(s) supported. This feature is new for Windows 3.1. *Transfer Normalized The normalized transfer function used to generate linear gray levels. This must be present. If none is required, include the nul function "{ }." The following is a list of PPD extensions. Extension Description ──────────────────────────────────────────────────────────────────────────── *AcceptsTrueType: True or false. If true, TrueType fonts will be downloaded natively using readhexsfnt operator. This is selected through the download option in the Advanced Options dialog box. If false, TrueType will not be displayed as a selection. This feature is new for Windows 3.1. *EndOfFile Indicates whether ^D is required to indicate the end of the file. This is true by default, and only needs to be included if this is false (that is, "*EndOfFile False"). *SetPage True or false. If true, the PostScript driver allows a custom paper size to be defined. This is implemented through the use of the setpage operator. If your printer supports the setpage operator in the same manner as Linotronic(R) printers, you can use this option. *TrueImageDevice: True or false. If true, the PostScript driver takes advantage of some optimizations available in TrueImage. Currently there is very little difference in the output. This feature is new for Windows 3.1. The following are the paper keywords used to show the paper sizes supported. Keyword Description ──────────────────────────────────────────────────────────────────────────── 10x14 10 x 14 inches physical size, oriented in portrait mode. 11x17 11 x 17 inches physical size, oriented in portrait mode. Can be used interchangeably with the keyword "Tabloid." A3 297 x 420 millimeters physical size, oriented in portrait mode. Refers to the International Standards Organization (ISO)/(JIS) A3 paper size. A4 210 x 297 millimeters physical size, oriented in portrait mode. A4Extra 9.27 x 12.69 inches physical size. A4Small 210 x 297 millimeters physical size, but with a reduced-size imageable area of 7.47 x 10.85 inches that is centered on an A4 page. Supports the Adobe PostScript paper definitions. A5 148 x 210 millimeters physical size, oriented in portrait mode. B4 250 x 354 millimeters physical size, oriented in portrait mode. Refers to the Japanese Industrial Standard (JIS) B4 paper size. B5 182 x 257 millimeters physical size, oriented in portrait mode. Folio 8.5 x 13 inches physical size, but with a reduced-size imageable region, oriented in portrait mode and centered on the folio sheet. Supports the Adobe PostScript paper definitions. Ledger 17 x 11 inches physical size, oriented in landscape mode (that is, the y-axis is on the shorter edge of the paper). Legal 8.5 x 14 inches physical size, oriented in portrait mode. LegalExtra 9.5 x 15 inches physical size. Letter 8.5 x 11 inches physical size. Refers to the standard paper type. LetterExtra 9.5 x 12 inches physical size. LetterSmall 8.5 x 11 inches physical size, but with a reduced-size imageable region that is centered on the page. Supports the Adobe PostScript paper definitions. Note 8.5 x 11 inches physical size, but with a reduced-size imageable region. This is used to reduce the size of the page buffer to give print jobs more memory. Quarto 215 x 275 millimeters physical size, but with a reduced-size imageable region, oriented in portrait mode and centered on the quarto sheet. Statement 5.5 x 8.5 inches physical size, oriented in portrait mode. Tabloid 11 x 17 inches physical size, oriented in portrait or tabloid mode (that is, the y-axis is on the longer edge of the paper). TabloidExtra 11.69 x 18 inches physical size. For paper extensions, five standard envelope sizes are recognized. The two groups of numbers following the word Envelope indicate the size of the envelope in points (where each point equals 1/72 of an inch). Extension Description ──────────────────────────────────────────────────────────────────────────── Envelope.279.639 #9 Envelope (3.875 x 8.875 inches) Envelope.297.684 #10 Envelope (4.125 x 9.5 inches) Envelope.324.747 #11 Envelope (4.5 x 10.375 inches) Envelope.342.792 #12 Envelope (4.75 x 11 inches) Envelope.360.828 #14 Envelope (5 x 11.5 inches) The following are the paper tray and bin keywords used to show and specify the input slots supported. Keyword Description ──────────────────────────────────────────────────────────────────────────── LargeCapacity This one can hold more than a standard amount of paper. Lower If there is more than one tray, this one is on the bottom. Middle This one is in the middle. OnlyOne There is only one tray. Upper If there is more than one tray, this one is on top. The following list describes the paper tray extensions. Extension Description ──────────────────────────────────────────────────────────────────────────── AutoSelect Printer can select automatically which feeder to use. This is followed by the code (or a nul command if no code is required) that is used to specify the autofeed mechanism. Envelope There is an envelope feeder. EnvelopeManual There is a manual envelope feeder. None There are no input feeders. This is treated as being the same as OnlyOne. The following keywords are required to support duplex printing. Keyword Definition ──────────────────────────────────────────────────────────────────────────── *Duplex DuplexNoTumble: "statusdict begin false settumble true setduplexmode end" *Duplex DuplexTumble: "statusdict begin true settumble true setduplexmode end" *Duplex None: "statusdict begin false setduplexmode end" *DefaultDuplex None If the PPD with correct *Duplex settings is built with the Windows 3.1 MKPRN utility, the driver expands the Options dialog box to give user control of duplex settings. PFM Files for PostScript Printers Because PostScript fonts are scalable, the PFM files for the PostScript fonts do not contain width tables. The files have the following form: PFMHEADER Header; /* font header */ PFMEXTENSION Extensions; /* extensions */ char DeviceName[]; /* printer device name */ char FaceName[]; /* font face name */ EXTTEXTMETRIC ExtTextMetrics; /* extended text metrics */ WORD ExtentTable[]; /* unscaled character widths */ DRIVERINFO DriverInfo; /* driver-specific information */ PAIRKERN KerningPairs[]; /* pair-kerning table (optional)*/ KERNTRACK KerningTracks[]; /* track-kerning table (optional)*/ The PostScript driver for Windows assumes all PostScript fonts are scalable fonts, so it ignores the dfPoints and dfPixHeight members in the PFM header. The members dfAvgWidth and dfMaxWidth are in units of 1000 units-per-em. Although the PostScript naming convention includes the attributes of the font (that is, bold and italic) in the font name, the attributes should be stripped from the font name and represented in the dfWeight and dfItalic members in the PFM header. The extent table is an array of 16-bit values containing the unscaled widths of the characters and assuming 1000 units-per-em. The range of the table should be from dfFirstChar to dfLastChar. The size of the table should be dfLastChar - dfFirstChar + 1. Pair-kern values should be in the same 1000 units-per-em measurement as the extents. As of this writing, we do not know of any application that uses the track-kern table. In the EXTTEXTMETRIC structure, the PostScript driver assumes the following values for each font: dfVertRes = 300 etmMasterHeight = 300 etmMasterUnits = 1000 In other words, the driver assumes all fonts use Adobe's standard 1000 units-per-em method for describing a font. You must build the extent table based upon 1000 units-per-em to be consistent with this restriction in the driver. The driver also assumes that the font may be scaled to any point size the application requests. We recommend that the true scaling range of the font be indicated in the etmMinScale and etmMaxScale members (in device units, at 300 dpi). The driver currently ignores these members. Because the Windows PostScript driver assumes all PostScript fonts are scalable fonts, it ignores the etmPointSize member. The etmSize member is not the point size, but rather the size (that is, the number of bytes) of the EXTTEXTMETRIC structure. As of this writing, we do not know of any application that uses the members in the EXTTEXTMETRIC structure except for etmKernPairs. If your font contains kern pairs, you must fill in the EXTTEXTMETRIC structure to indicate the number of kern pairs. Do not leave the other members blank; fill them in with reasonable values in the event an application does use them. The driver-specific data structure pointed to by dfDriverInfo is a null-terminated string containing the PostScript name for the font. There are two names for the font: ♦ The Windows name for the font which appears in the font list in the application's font dialog box. ♦ The PostScript name for the font, which can vary according to printer manufacturer and which the driver sends to the printer to select the font. Both strings must be null-terminated. The Windows name for the font is pointed to by dfFace and the PostScript name for the font is pointed to by dfDriverInfo. To create a PFM file for the internally-supported printers, Microsoft converts Font Metric (AFM) files to the PFM file format. These files, provided with the DDK, are ASCII files that define the metrics for each font. There are 63 AFM files supporting 63 unique fonts. Printers with resident fonts that are not supported in the current version of the driver will need to define those files as soft fonts. If you need to define a font that is not available currently in the PostScript printer driver, you will need to modify the driver sources to add additional AFM files. Please refer to the PostScript driver's MAKE file that is included on the DDK disks for more information on how the driver builds AFM and PFM files. Printers Setup File The printers setup file (OEMSETUP.INF) should reside on the disk distributed with the WPD file. This file follows the standard format used in the Windows CONTROL.INF file. It contains a [io.device] section that lists the PostScript printer names for each set of WPD files included on the disk. The file has the same form as the following example: [io.device] 7:pscript.DRV,7:L630_52&.WPD,"Linotronic 630","DEVICESPECIFIC" If the user tries to install a printer that is already installed, the printer driver will ask whether the previous WPD file should be updated. Manufacturers that are already supported internally in the driver should not provide WPD files with names that conflict with those used internally. If an update is required, add the PostScript version number to the printer name (in both the OEMSETUP.INF file and the "*NickName" section of the PPD file). Compiling with the MKPRN Utility The MKPRN utility, an MS-DOS utility, takes a PPD file and all the PFM files referenced in the PPD file, and produces the WPD file needed for a printer to be supported by the Windows PostScript printer driver. The utility has the following command syntax: mkprn [/v] [/s] ppd-file Parameter Description ──────────────────────────────────────────────────────────────────────────── /v An optional verbose switch. This causes MKPRN to print messages as it processes various elements in the PPD file. This may be useful for debugging PPD files. /s Suppresses combining the PSS, CAP, and DIR files into one WPD file. This is used only when building the driver sources, and is not intended for use by external printers. ppd-file This is the base filename (with no extension) of the PPD file to be processed. The WPD file shares this base filename. Error messages are printed for fonts that are not found and for identifiers that are not recognized. If fonts are not found, they are not built into the WPD file and have to be added as soft fonts as described in the next section. Soft Fonts A soft font installer is not available yet for the PostScript printer driver. Therefore, it is up to the printer manufacturer to install additional fonts as soft fonts by adding the appropriate WIN.INI entries. The softfontn settings in WIN.INI can be used for several different purposes. Basically, they inform the driver that a given printer has extra fonts available and, if necessary, indicate a file that needs to be downloaded to make that font available. If there is a second file listed in a softfontn setting, it is assumed that it needs to be downloaded to activate the given font. Thus, soft fonts can be used to support resident printer fonts that have been downloaded previously, that reside on a printer's hard drive, or that are available in some other form. The softfonts setting indicates how many soft fonts are installed and listed. The maximum number of soft fonts allowed is based on available memory and other considerations. The maximum number of soft fonts is at least 450. Each softfontn setting references the PFM file associated with a soft font and, optionally, the soft font that will be downloaded to the printer at print time. Each filename may be a complete pathname. The two forms of soft fonts supported are described in the following subsections. Adobe Soft-Font Format Adobe soft fonts (files with an .AGB extension) are recognized by the following string: %!PS-AdobeFont The string must be located at offset 6 in the file. The first 6 bytes are defined by the following data structure: typedef struct{ unsigned char flag; char type; /* 1 means data is ASCII, 2 means binary */ /* (convert to ascii) */ long length; /* length of the data that follows */ } HDR; The members indicate the length of the soft font as well as the type (ASCII or binary). Binary forms are converted to hexadecimal ASCII by the driver; ASCII fonts are copied directly. Non-Adobe Soft-Font Format Fonts that do not have the above-mentioned signature are copied to the output stream. Therefore, the whole file must be in PostScript code that describes the font. Testing the WPD Files PostScript printer manufacturers should test their WPD files before distribution. Do the following: 1 Copy the OEMSETUP.INF and WPD files to a disk. 2 Install the printer by choosing the Add button in the Printers dialog box in Control Panel. Select the appropriate printer and choose the Install button. 3 Select the newly installed printer from the Installed Printers list box, and set it to be the default printer. 4 Test the following features of your printer: ♦ *NickName. Make sure that the model name in the Setup dialog box is the same as the name in the OEMSETUP.INF file, and the *NickName field of the PPD. ♦ Paper Sizes. Make sure that all the paper sizes are available and that the imageable areas are correct. ♦ Paper Sources. Test that all the paper sources can be selected properly. ♦ Normalized Transfer Function. Use an application (for example, Micrografx Designer 2.0) that can generate gradiated fills to make sure that gray levels are represented in a linear fashion. If you find any problems, make the appropriate changes to the PPD file, rebuild the WPD file, and install the new WPD over the existing one. Note: The description string in OEMSETUP.INF needs to match the "*NickName" keyword from the PPD file. ♦