Linux 版 (精华区)
发信人: netiscpu (说不如做), 信区: Linux
标 题: [B] Red Hat Linux Unleashed (25)
发信站: 紫 丁 香 (Sat Jul 25 03:11:59 1998), 转信
Ghostscript
_________________________________________________________________
o What Is Ghostscript?
# Ghostscript Information
o Installation
o The Ghostscript Interpreter
# Getting Help While in gs
o Choosing the Output Device
o Paper Size Configuration
o Environment Variables
o Configuring for X Window
o Command-Line Arguments
o PostScript Viewer Ghostview
# Keyboard Accelerators
# X Resources
o Using Other Fonts
o Getting More Help
o Summary
_________________________________________________________________
25
Ghostscript
This chapter covers installation and use of Ghostscript, a PostScript
interpreter. Almost everything related to Linux is in PostScript. If
you have a PostScript printer, you simply send the file to the printer
for a hardcopy.
What Is Ghostscript?
Ghostscript is actually a set of programs. Collectively, these
programs provide two important features:
* An interpreter for the PostScript language.
* A library of C functions for implementing primitive PostScript
constructs.
______________________________________________________________
NOTE: PostScript is a trademark of Adobe Systems, Incorporated.
______________________________________________________________
Ghostscript has been ported to several platforms from PCs, OS/2, Apple
Macintoshes, Ataris, to various flavors of UNIX, for example, Sun
workstations, IBM AIX machines, and so on. Since Ghostscript is
written in C, chances are that it will be portable to your platform.
If you support X11, you will probably be able to run Ghostscript.
Several executable files come with Ghostscript. Some of the
executables are also used by other packages under Linux. For example,
HylaFAX (Chapter 59, "Using FlexFAX, sendfax, and mgetty") uses the
main Ghostscript program, gs. In short, if you use Linux, you will
find a need for Ghostscript.
Ghostscript Information
The primary contact for getting information about Ghostscript is:
Aladdin Enterprises
P.O. Box 60264
Palo Alto, CA 94306
voice (415) 322-0103
FAX (415) 322-1734
ghost@aladdin.com
In fact, the Ghostscript package that you get with Linux is from
Aladdin Enterprises. The information about Ghostscript is best
summarized in its README file:
"L. Peter Deutsch, president of Aladdin Enterprises, was the original
creator, and is the primary developer and maintainer, of Ghostscript.
Aladdin Enterprises owns the copyright on Ghostscript; Ghostscript is
distributed with the GNU General Public License, and is also available
for commercial licensing."
Installation
To run Ghostscript, you need the executable program and some external
initialization files:
/usr/lib/ghostscript/bdftops.ps
/usr/lib/ghostscript/decrypt.ps
/usr/lib/ghostscript/font2c.ps
/usr/lib/ghostscript/gs_dbt_e.ps
/usr/lib/ghostscript/gs_dps1.ps
/usr/lib/ghostscript/gs_fonts.ps
/usr/lib/ghostscript/gs_init.ps
/usr/lib/ghostscript/gs_lev2.ps
/usr/lib/ghostscript/gs_statd.ps
/usr/lib/ghostscript/gs_sym_e.ps
/usr/lib/ghostscript/gs_type0.ps
/usr/lib/ghostscript/gslp.ps
/usr/lib/ghostscript/impath.ps
/usr/lib/ghostscript/landscap.ps
/usr/lib/ghostscript/level1.ps
/usr/lib/ghostscript/prfont.ps
/usr/lib/ghostscript/ps2ascii.ps
/usr/lib/ghostscript/ps2epsi.ps
/usr/lib/ghostscript/ps2image.ps
/usr/lib/ghostscript/pstoppm.ps
/usr/lib/ghostscript/quit.ps
/usr/lib/ghostscript/showpage.ps
/usr/lib/ghostscript/type1ops.ps
/usr/lib/ghostscript/wrfont.ps
/usr/lib/ghostscript/uglyr.gsf
/usr/lib/ghostscript/Fontmap
The Ghostscript file set includes a set of fonts (.gsf files). You
should have them online as well.
Installing Ghostscript on a Linux system simply requires getting it
from the CD-ROM or Internet. The name of the executable is gs.
You can build Ghostscript on your machine if you want to. The
makefiles that come with the sources will install all the files and
directories under your /usr/local directory.
The fonts for Ghostscript are stored in /usr/lib/ghostscript/fonts.
The Ghostscript Interpreter
The Ghostscript interpreter is the gs command in /usr/bin/gs. This is
an interactive interpreter that also reads in files for its input. To
invoke the gs interpreter, use the command
gs [filename1] ... [filenameN]
The interpreter will read in the files in sequence and interpret them.
After doing this, it reads further input from the primary input stream
(normally the keyboard). Each line (that is, characters up to a
<return>) is interpreted separately. To exit from the interpreter,
type quit and press the Return key. The interpreter also exits
gracefully if it encounters end-of-file. Typing the interrupt
character (Ctrl-C), is also safe.
See Figure 25.1 for the input to the interpreter. (Your version number
may be different than that shown in the figure.) The output is shown
in a separate window as shown in Figure 25.2 (which shows the FlexFAX
FAQ). The file in this example is the FAQ for the HylaFAX program (see
Chapter 59) and is called fax-112894.ps. You can get this file via
Mosaic (see Chapter 56, "Using Mosaic and Netscape") from www.vix.com
from the HylaFAX directory.
Figure 25.1. The gs interpreter.
Figure 25.2. The output from gs interpreter.
Getting Help While in gs
The gs interpreter recognizes several arguments. We will cover most of
the important ones in this chapter. However, you can get help from gs
too. Either the -h or -? option tells gs to print out a help screen.
The help screen also lists all available devices for gs on your
system.
Choosing the Output Device
Ghostscript may be built with multiple output devices. Ghostscript
normally opens the first one and directs output to it. To use device
Laserjet as the initial output device, include the following argument
in the command line:
-sDEVICE=laserjet
______________________________________________________________
NOTE: Command line arguments to gs can appear anywhere on the
command line. Once specified, these arguments apply to all
subsequent files listed in the command line. These arguments will
not apply to any files specified before the argument. So if you
have important arguments like sDEVICE, specify these arguments
before you specify the PostScript file.
______________________________________________________________
______________________________________________________________
NOTE: PostScript files are usually specified with the .ps
extension.
______________________________________________________________
For example, for printer output in a normal configuration that
includes a Laserjet printer driver, you might use the shell command
gs -sDEVICE=laserjet showme.ps
Alternatively, in the interpreter you can type
(laserjet) selectdevice
(showme.ps) run
All output then goes to the printer instead of the display until
changed. You can switch devices at any time by using the selectdevice
function, for example,
(vga) selectdevice # for VGA screen
or
(nec) selectdevice #for NEC printer
As yet a third alternative, you can define an environment variable
GS_DEVICE as the desired default device name. The order of precedence
for these alternatives, highest to lowest, is this:
selectdevice
(command line)
GS_DEVICE
(first device in build list)
To select the density on a printer, use the command
gs -sDEVICE=<device> -r<xres>x<yres>
For example, on a nine-pin, Epson-compatible printer, you can get the
lowest-density (fastest) mode with the command
gs -sDEVICE=epson -r60x72
For the highest-density mode with Epson printers, use
gs -sDEVICE=epson -r240x72.
If you select a printer as the output device, Ghostscript also enables
you to control where the device sends its output.
-sOutputFile=print%d.xyz
For compatibility with older versions of Ghostscript, -sOUTPUTFILE=
also works.
The %d is a printf format specification. You can use other formats
like %02d. Each file will receive one page of output. Alternatively,
to send the output to a single file bigfile.xyz, with all the pages
concatenated, use the command line argument: -sOutputFile=foo.xyz.
On UNIX-like systems, you can send the output directly to a pipe. For
example, to pipe the output to the command lpr (which, on many UNIX
systems, is the command that spools output for a printer), use the
switch
-sOutputFile=\|lpr
Don't forget to escape the pipe symbol (|). You can also send output
to stdout for piping with the dash as the output file. That is, use
the option -sOutputFile=-. In this case you must also use the -q
switch to prevent Ghostscript from writing messages to stdout.
To find out what devices are available, type "devicenames ==" after
starting up Ghostscript.
Paper Size Configuration
Ghostscript is normally configured to expect U.S. letter size paper.
To select a different paper size as the default, use the argument
-sPAPERSIZE=known_paper_size. (You can create your own paper sizes
with the devs.mak file.) Generally, you have a large selection
available. The entire list can be found in the file
/usr/lib/ghostscript/gs_statd.ps
Print this file out if you can, to keep it handy. Some examples of
setting the paper size are
-sPAPERSIZE=a4
-sPAPERSIZE=legal
-sPAPERSIZE=11x17
-sPAPERSIZE=ledger
______________________________________________________________
NOTE: A PostScript file may explicitly specify the paper size. In
this case, the file's specification will override any command line
argument specification.
______________________________________________________________
Environment Variables
Ghostscript uses these environment variables: GS_LIB, GS_LIB_DEFAULT,
and GS_FONTPATH.
When looking for the initialization files (gs_*.ps), the files related
to fonts, or the file for the run operator, Ghostscript first tries
opening the file with the name as given (that is, using the current
working directory if none is specified). If this fails, and the
filename doesn't specify an explicit directory or drive (that is,
doesn't begin with / on UNIX), Ghostscript will try directories in the
following order:
* The GS_LIB variable specifies several directories for gs to look
in for files if a full path name of an input file is not
specified. The directory names are separated by colons (like the
PATH command).
* The GS_LIB_DEFAULT variable is similar to the GS_LIB variable and
is searched if GS_LIB's directories showed nothing. Both of these
variables (GS_LIB and GS_LIB_DEFAULT) can be overridden by the -I
argument.
* The GS_FONTPATH environment variable is a list of directories for
PostScript fonts. All those files and fonts listed in this
directory are added to gs's internal copy of the Fontmap. A
Fontmap is a catalog of fonts and the files that contain them.
______________________________________________________________
NOTE: Ghostscript will create temporary files by using the TEMP
environment variable as the location of the /tmp directory. These
files are named gs_XXXXX, where XXXXX is replaced by a number or a
string of jumbled characters. Ghostscript doesn't do a very good
job of deleting temporary files when it exits. If you see your /tmp
space being used by these files you may have to delete them using
the rm /tmp/gs_* command.
______________________________________________________________
Configuring for X Window
Ghostscript looks for the resources under the program name ghostscript
and class name Ghostscript in the .Xdefaults file. To set a resource,
put the resource in .Xdefaults in the following form:
Ghostscript*geometry: -0+0
Ghostscript*xResolution: 72
Ghostscript*yResolution: 72
Then load the defaults into the X server:
% xrdb -merge ~/.Xdefaults
Table 25.1 lists the options available to you.
Table 25.1. Ghostscript resources.
Name Class Default
background Background white
foreground Foreground black
borderColor BorderColor black
borderWidth BorderWidth 1
geometry Geometry NULL
xResolution Resolution calculated
yResolution Resolution calculated
useExternalFonts UseExternalFonts true
useScalableFonts UseScalableFonts true
logExternalFonts LogExternalFonts false
externalFontTolerance ExternalFontTolerance 10.0
palette Palette Color
maxGrayRamp MaxGrayRamp 128
maxRGBRamp MaxRGBRamp 5
useBackingPixmap UseBackingPixmap true
useXPutImage UseXPutImage true
useXSetTile UseXSetTile true
regularFonts RegularFonts
symbolFonts SymbolFonts
dingbatFonts DingbatFonts
Here are a few points on these resources:
* The geometry resource only affects window placement. This does not
affect the position of the image on the display in the window.
* All resolution numbers are given in pixels per inch.
* The font tolerance gives the largest acceptable difference in the
height of the screen font. The tolerance is expressed as a
percentage of the height of the desired font.
* The palette resource can be used to restrict Ghostscript to using
a grayscale or monochrome palette.
* The maxRGBRamp and maxGrayRamp control the maximum number of
colors that Ghostscript allocates ahead of time for dithering.
Ghostscript will never pre-allocate more than half of the cells in
a color map.
To use native X11 fonts, Ghostscript must map PostScript font names to
the XLFD font names. The regularFonts, symbolFonts, and dingbatFonts
resources give the name mapping for different encodings. The XLFD font
name in the mapping must contain seven dashes. The X driver adds the
additional size and encoding fields to bring the total number of
dashes in the font name to 14. The default font mappings are found in
the FontMap file in /usr/lib/ghostscript or check the man pages.
Command-Line Arguments
Ghostscript takes a lot of command-line arguments. Generally you would
want to put these in a shell script file instead of having to type
them in all the time. Some of the most often used arguments are listed
here. For a comprehensive list check out the documents in
/usr/lib/ghostscript/doc. Let's look at the most commonly used
arguments:
* @filename The filename specified here will contain a list of all
the input file names. This beats typing in long names on every
execution of gs with lots of input files.
* -Idirectories Adds the list of directories at the head of the
library files' search path.
* -ffilename Executes the given file, even if its name begins with a
-.
* -Dname=token or -dname=token Defines a name with the given token.
The token must not contain any whitespace. You must specify each
token with its own -Dname option. -Dname or -dname without the =
will set the value to null.
* -Sname=string or -sname=string Defines a string.
______________________________________________________________
NOTE: The differences between -d and -s are these:
-dfoo=hello is equivalent to /foo hello def
-sfoo=hello is equivalent to /foo (hello) def
______________________________________________________________
* -q Suppresses normal startup messages.
* -gnumber1xnumber2 Number1 is the width, Number2 is the height of
the display device. This is for devices that enable width and
height to be specified. This is equivalent to
-dDEVICEWIDTH=number1 and -dDEVICEHEIGHT=number2.
* -rnumber or -rnumber1xnumber2 This is for the benefit of devices
(such as printers) that support multiple X and Y resolutions. You
can also use -dDEVICEXRESOLUTION=number1 and
-dDEVICEYRESOLUTION=number2.
* - Uses standard input instead of the file. Ghostscript will read
from stdin until reaching end-of-file, and execute it as another
file. After the end of file, gs will process any other items as
arguments but will not go into interactive mode.
* -dDISKFONTS This argument causes individual character outlines to
be loaded from the disk the first time they are encountered.
Normally Ghostscript loads all the character outlines when it
loads a font. This may enable loading more fonts into RAM at the
expense of slower rendering.
* -dNODISPLAY Suppresses the normal initialization of the output
device. This may be useful when debugging.
* -dNOPAUSE Disables the prompt and pauses at the end of each page.
This is useful for applications where another program is "driving"
Ghostscript.
* -dNOPLATFONTS Disables the use of fonts supplied by your machine.
It is needed if the platform fonts look bad when compared to
scaleable fonts.
* -dSAFER Disables the deletefile and renamefile operators and the
ability to open files in any mode other than read-only.
* -sDEVICE=device Selects an alternate initial output device.
* -sOutputFile=filename Selects an alternate output file instead of
the default destination.
PostScript Viewer Ghostview
Ghostview is used to display encoded PostScript files. Ghostview is
free. It was written and copyrighted by Tim Theisen. The ghostview
command shows PostScript documents using Ghostscript.
Use the command line below to view a text file.
$ ghostview [filename]
The ghostview program will create an X window, open the file, and
display it. If the filename is '-', ghostview will read from stdin.
The ghostview program provides an X11 user interface for the
Ghostscript interpreter. ghostview and Ghostscript function as two
cooperating programs. ghostview creates the viewing window and
Ghostscript draws in it.
______________________________________________________________
NOTE: Please use Ghostview to view files, especially those that
require typesetting before sending them to the printer. You can
save a lot of trees this way and get a quicker response about what
to expect on the output. There are many programmers who still print
out files to see what the output would look like instead of
previewing on the screen.
In fact you may not even have to print out a document if you intend
to send it to a remote site. If you have to FAX it, use HylaFAX
(Chapter 59) with your FAX/modem to send it directly. If you have
to e-mail it, uuencode it and then send it out.
______________________________________________________________
Ghostview has a bewildering number of options. You do not have to use
any of these options at all. Most of the options are there to override
any Xresources that you set in .Xdefaults. Let's look at the main
window, which consists of a main viewer and control menus (of
HylaFAX). (See Figure 25.3.)
Figure 25.3. Ghostview main window.
The main viewport is on the right side of the main window. If the page
is larger than the viewport, there will be scroll bars along the
bottom and right edges of the viewport. To the left of the viewport is
the table of contents. If the PostScript file has document structuring
convention (DSC) comments, the table of contents will display the page
labels (these are usually page numbers). To the left of the table of
contents is a menu box. Each push button brings up a pop-up menu.
Above the menu box and table of contents there are three optional
labels that contain the title, date, and locator.
The title label contains the document title found in the DSC comments.
If no title can be found, the filename is used in its place. The date
label contains the document date found in the DSC comments. If no date
can be found, the last modified date of the file is used in its place.
Since the title and date labels may be clipped by the main viewport,
the date and title labels are pushbuttons that bring up a pop-up
window with the title or date. These pop-up windows also show the
document icon when the displayed string comes from the DSC comments.
The locator shows the location of the cursor in the viewport. The
location is expressed in the default user coordinate system. The
locator is useful for measuring bounding boxes. Within the main
viewport, the mouse cursor is a "target" when Ghostscript is doing
work. The cursor is a crosshair when Ghostscript is idle.
______________________________________________________________
NOTE: When moving to another page in a document, it is generally
best to wait for Ghostscript to become idle. Ghostscript does not
handle a series of mouse clicks very well while it's working and
can hang. You then have to use the kill command to get rid of it,
and start over.
______________________________________________________________
Ghostview will always check to see if the file has been modified just
before it displays a page or when the application is de-iconified. If
the file has changed, it will re-open the file. This causes a bit of
an overhead, but is helpful when you are trying to edit a file from
another program and need to see your progress.
Clicking anywhere within the viewport will pop up a zoom window. The
window is centered on the location that was clicked. Clicking with the
left mouse button pops up a low-resolution zoom window. Clicking with
the center mouse button pops up a medium-resolution zoom window.
Clicking with the right mouse button pops up a high-resolution zoom
window.
In the table of contents, the left mouse button selects text and the
right mouse button extends selections. However, clicking on a page
label with the center mouse button will display that page. The page
being displayed is marked with a greater than symbol (>) in the right
margin of the table of contents.
There are five buttons in the menu box. These are listed below:
* File This menu enables you to open, reopen, print, show a
copyright message, and quit the application. A Select File dialog
box will appear when you click the open button. The Select File
dialog widget enables you to select a file by typing the path or
by browsing in directory listings and selecting entries with the
mouse. The Select File dialog box is system modal; that is, no
other controls in ghostview will be active during this time.
* Page This pop-up menu controls which page you display. Next shows
the next page, Redisplay redraws the current page, Previous shows
the previous page, Mark and Unmark set a page in the table of
contents as marked and unmarked.
* Magstep This menu controls the magnification of the display. Zero
implies no magnification (what you see is what you get). The
multiplication factor is 1.2, so with a magstep of -1, the
document is reduced by -1.2, a magstep of 1 zooms in by 1.2.
* Orientation This enables you to select either a landscape or
portrait orientation of the display. You can also flip the image
with the Upsidedown to see FAXed documents. The Seascape option
rotates the image 90 degrees counterclockwise.
* Media The entries on the Media menu set the page media. The
standard sizes you can select are: Letter, Tabloid, Ledger, Legal,
Statement, Executive, A3, A4, A5, B4, B5, Folio, Quarto, and
10�14.
Keyboard Accelerators
Some of the pop-up menu commands can be executed with the keyboard.
The pop-up menu has to be active (in other words, selected by the user
for input) for the action to have effect. Some of the bindings are
listed in Table 25.2.
Table 25.2. Keyboard shortcuts.
Key Action
Q The Quit menu button
O The Open... menu button on the File menu
R The Reopen... menu button on the File menu
S The Save marked pages on the File menu
P The Print marked pages on the File menu
Shift-P The Print all pages on the File menu
BackSpace, B space The Previous menu button on the Page menu
Return, F period The Next menu button on the Page menu
Ctrl-L The Redisplay menu button on the Page menu
M The Mark menu button on the Page menu
[lb] The Unmark menu button on the Page menu
0-5 Selecting the 0 through 5 menu button on the Magstep menu
+ Increases the Magstep by 1
- Decreases the Magstep by 1
U Scrolls Up
D Scrolls Down
H Scrolls Left
L Scrolls Right
X Resources
You can set the following resources for Ghostview. Only the most
frequently used resources are listed. Please check the lengthy man
page for Ghostview script for its long list of resources.
* showTitle (class Labels) Displays the Title comment. The default
is true.
* showDate (class Labels) Displays the % %% %Data comment. The
default is true.
* showLocator (class Labels) Displays the locator. The default is
true.
* autoCenter (class AutoCenter) Centers the page in the viewport
whenever the page size changes. The default is true.
* horizonalMargin (class Margin) Shows how many pixels ghostview
should reserve for horizontal window decorations. The default
value is 20.
* verticalMargin (class Margin) Shows how many pixels ghostview
should reserve for vertical window decorations. The default value
is 44.
* minimumMagstep (class Magstep) Sets the smallest magstep to
display. The default is -5.
* maximumMagstep (class Magstep) Sets the largest magstep to
display. The default is 5.
* magstep (class Magstep) Sets the default magstep. The default is
0.
* orientation (class Orientation) Sets the default orientation. The
default is Portrait.
* page (class Page) Gives the initial page to display.
* pageMedia (class PageMedia) Sets the default page media. The
default is Letter.
* forceOrientation (class Force) Forces the orientation on the
document. The default is false.
* forcePageMedia (class Force) Forces the page media on the
document. The default is false.
* swapLandscape (class SwapLandscape) Swaps the meaning of Landscape
and Seascape. The default is false.
* printCommand (class PrintCommand) Sets the command used for
printing.
* printerVariable (class PrinterVariable) Gives the name of the
printer environment variable. The default value is PRINTER.
* busyCursor (class Cursor) The cursor shown when Ghostscript is
drawing to the window. This is defaulted to a target icon.
* cursor (class Cursor) The cursor shown when Ghostscript is idle.
The default cursor is the crosshair.
* safer (class Safer) Tells Ghostscript whether to run in safer
mode. The default value is true.
Remember that almost all of these resources can be set with the
command line argument. For example, the -title argument is equivalent
to setting Ghostview.showTitle resource to True, whereas the -notitle
argument is equivalent to setting the Title resource to False.
Similarly, you can turn the date on or off with the -date and -nodate
arguments, respectively.
Using Other Fonts
The versions of Ghostscript come with a set of default fonts that you
can use with any program capable of reading PostScript Type 1 and Type
3 fonts. If you have created your own Type 1 or Type 3 fonts, or have
purchased some fonts from another source, you can use these with
Ghostscript. Place your fonts in the lib/ghostscript/fonts directory.
Then edit the lib/ghostscript/FontMap file to add a line telling
Ghostscript where to find the font. For example,
/Helvetica (hlv_xyz.pfb);
where hlv_xyz.pfb is the name of the font file you have just added.
You do not have to reset any X resources for this to work. Simply
place the file in the directory, edit the FontMap and restart gs.
Getting More Help
Aladdin Enterprises, the inventors of Ghostscript, do not have the
resources to respond to questions from general users of Ghostscript.
There are plenty of other places where you can get very detailed
information about Ghostscript.
If you have access to newsgroups, post your questions to
gnu.ghostscript.bug. There are literally hundreds of Ghostscript users
all over the world who are very willing to help you. After all, we all
started learning on our own. Using this newsgroup is perhaps the
quickest way to get more information on gs.
If you have access to Internet mail, but not news, send e-mail to
bug-ghostscript@prep.ai.mit.edu">bug-ghostscript@prep.ai.mit.edu. If
you are having trouble with a specific device driver, look in the file
devs.mak and see if it is a user-maintained driver. If so, please
contact directly the person listed.
There are several files in the /usr/lib/ghostscript/doc directory
which can provide more information. Some of these files are:
* readme.doc Information about problems, major changes, and new
features in the current release.
* NEWS A detailed history of changes in the most recent Ghostscript
releases.
* use.doc Information about how to install and use Ghostscript.
* devices.doc Detailed information about specific devices that
Ghostscript supports.
* make.doc How to install, compile, and link Ghostscript.
* gs.1 The man page for Ghostscript.
* fonts.doc Information about the fonts distributed with
Ghostscript, including how to add or replace fonts.
* language.doc A description of the Ghostscript language and its
differences from the documented PostScript language.
* psfiles.doc Information about the .ps files distributed with
Ghostscript other than fonts.
* drivers.doc The interface between Ghostscript and device drivers.
* ps2epsi.doc Documentation for the PostScript to EPSI conversion
utility. Most commercial word processing packages can import EPSI
documents for typesetting.
* hershey.doc Information about the Hershey fonts, which are the
basis of some of the Ghostscript fonts.
* history.doc A history of changes in older Ghostscript releases.
* lib.doc Information about the Ghostscript library.
Summary
This chapter scratched the surface of a very important PostScript
processing program called Ghostscript. The executable file for
Ghostscript is called gs. You can use gs to decode PostScript files
for displaying or printing hard copies.
Ghostscript is also used by other programs as a filter for working
with PostScript printers that cannot switch from PostScript to text
and back just by looking at a document. In this case, the gs command
is used to convert text to PostScript with an output filter for lp
before sending the text to a PostScript printer. As another example,
HylaFAX uses gs as its primary PostScript output filter program.
Ghostview is an X Window—based program that provides a canvas for
ghostscript to write its output to. Ghostview enables you to scroll
through a multi-page document, zoom in and out, and save marked pages.
The ability to view EPSI or PostScript via Ghostscript saves time and
paper when typesetting documents.
--
Enjoy Linux!
-----It's FREE!-----
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