GNU gv Manual


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GNU gv

GNU gv - View PostScript and PDF documents using ghostscript.

This is the First edition of the GNU gv Manual, updated for gv version 3.6.9.

Copyright © 1995, 1996, 1997 Johannes Plass

Copyright © 2004 José E. Marchesi

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU General Public License, Version 3 or any later version published by the Free Software Foundation.

Table of Contents


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1 Introduction

GNU gv allows to view and navigate through PostScript and PDF documents on an X display by providing a user interface for the ghostscript interpreter.

Please note that gv is derived from Tim Theisen's ghostview.


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2 Invoking gv

Usage: gv [OPTION]... [FILE]
PostScript and PDF viewer.
  [-]-monochrome                      display document using only black and white
  [-]-grayscale                       display document without colors
  [-]-color                           display document as usual
  [-]-safer                           start ghostscript in safe mode
  [-]-nosafer                         do not start ghostscript in safe mode
  [-]-quiet                           start ghostscript with the -dQUIET option
  [-]-noquiet                         do not start ghostscript with the -dQUIET option
  [-]-infoSilent                      do not show any messages in the info popup window
  [-]-infoErrors                      do not show warning messages in the info popup window
  [-]-infoAll                         do show all messages in the info popup window
  [-]-arguments=ARGS                  start ghostscript with additional options as specified
                                      by the string ARGS
  [-]-page=LABEL                      display the page with label LABEL first
  [-]-center                          the page should be centered automatically
  [-]-nocenter                        the page should not be centered automatically
  [-]-media=MEDIA                     selects the paper size to be used
  [-]-orientation=ORIENTATION         sets the orientation of the page
  [-]-scale=N|f.f                     selects the scale N, or arbitrary scale f.f
  [-]-scalebase=N                     selects the scale base N
  [-]-swap                            interchange the meaning of the orientations landscape
                                      and seascape
  [-]-noswap                          do not interchange the meaning of the orientation
                                      landscape and seascape
  [-]-antialias                       use antialiasing
  [-]-noantialias                     do not use antialiasing
  [-]-dsc                             dsc comments are respected
  [-]-nodsc                           dsc comments are not respected
  [-]-eof                             ignore the postscript EOF comment while scanning
                                      documents
  [-]-noeof                           do not ignore the postscript EOF comment while
                                      scanning documents
  [-]-pixmap                          use backing pixmap
  [-]-nopixmap                        do not use backing pixmap
  [-]-watch                           watch the document file for changes
  [-]-nowatch                         do not watch the document file for changes
  [-]-help                            print a help message and exit
  [-]-usage                           print a usage message and exit
  [-]-resize                          fit the size of the window to the size of the page
  [-]-noresize                        do not fit the size of the window to the size of the page
  -geometry [<width>][x<height>][{+-}<xoffset>{+-}<yoffset>]
  [-]-ad=FILE                         read and use additional resources from FILE
  [-]-style=FILE                      read and use additional resources from FILE. These resources
                                      have lower priority than those provided on the context of --ad
  [-]-password=PASSWORD               Sets the password for opening encrypted PDF files
  [-]-spartan                         shortcut for --style=gv_spartan.dat
  [-]-widgetless                      shortcut for --style=gv_widgetless.dat
  [-]-fullscreen                      start in fullscreen mode (needs support from WM)
  [-]-presentation                    Presentation mode (fullscreen, Fit to window,
                                      widgetless and no resizing of window)
  [-]-version                         show gv version and exit
file
The name of the file to be displayed. The file ending .ps may be omitted. file may point to a compressed file (gzipped, bzipped, zipped or compressed). Viewing PDF files requires at least ghostscript version 4.x.
--ad=file
Read and use additional resources from the file file. These resources have higher priority than those provided in the context of the --style option.
--antialias, --noantialias
Whether to use antialiasing.
--arguments=args
Start ghostscrip with additional options as specified by the string args.
--center, --nocenter
Whether the page should be centered automatically.
--dsc, --nodsc
Determines if document structuring convention (DSC) comments should be respected or ignored. If --nodsc is used gv will not attempt to examine the structure of the document but will pass the file to the ghostscript interpreter as a whole. In this case no page numbers are shown and freely moving around in the document is not possible. This option may help when viewing files not conforming to the document structuring conventions.
--eof, --noeof
Defines the behaviour of the postscript scanner used to examine the structure of the document. If --noeof is used the scanner will ignore end of file (EOF) comments. This may help when viewing documents which import other documents without enclosing them within the proper "BeginDocument" and "EndDocument" comments. If --eof is used, the scanner treats an EOF comment as marking the end of the file.
--fullscreen
Selects the fullscreen mode.
--infoSilent
Do not show any ghostscript messages in an info popup window.
--infoErrors
Only show error messages from ghostscript in an info popup window.
--infoAll
Shows all ghostscript messages in an info popup window.
--pixmap, --nopixmap
If --pixmap is used gv tries to maintain off-screen regions of the displayed page by allocating a sufficiently large pixmap. If --nopixmap is used the X Server is responsible for maintaining obscured portions of the displayed page (see also the useBackingPixmap resource).
--version
Print the version number of gv to standard output and exit.
--help, --usage
Display a short help message and exit.
--scale=n
n must be an integer or a positive float. In case n is an integer, n selects the scale entry n relative to the scale 1.0. With the special value of -1000 Fit to page is selected, and likewise with the value of -1001 Fit widthto page is selected. In case n is a float, n selects an arbitrary scale.
--scalebase n
Selects the scale base n.
--monochrome, --grayscale, --color
Sets the color palette to be used.
--media=media
Selects the paper size to be used. Valid values are names of paper sizes that appear in the list of page medias as given by the medias resource.
--page=label
Display the page with label label first.
--orientation=orientation
Sets the orientation. Valid values for orientation are portrait, landscape, seascape and upsidedown.
--quiet, --noquiet
Whether to start ghostscript with the -dQUIET option.
--resize, --noresize
Whether ghostscrip is allowed to automatically fit the size of its window to the size of the displayed page.
--password=PASSWORD
When opening a file, use PASSWORD to decrypt it. This Option is usefull for viewing encrypted PDF files.
--presentation
Is actually a shortcut for --fullscreen --noresize --scale=-1000 --widgetless.
--safer, --nosafer
Whether to start ghostscript with the -dSAFER option.
--spartan
This is a shortcut for --style=gv_spartan.dat.
--style=file
Read and use additional resources from the file file. These resources have lower priority than those provided in the context of the --ad option.
--swap, --noswap
Whether to interchange the meaning of the orientations landscape and seascape.
--watch, --nowatch
The --watch option causes gv to check the document periodically. If changes are detected gv will automatically display the newer version of the file. The document is by default checked once every second. This can be changed via the watchFileFrequency resource. Note that sending gv the SIGHUP signal also causes an update of the displayed document. This method may be used by document creators to trigger gv remotely.
--widgetless
This is a shortcut for --style=gv_widgetless.dat.


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3 Resources


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3.1 Resource files

In general gv does not depend on any external resource files. However, when starting gv, preferences are read from

a system specific resource file.
The name of this file is GV and is installed on as part of gv's architecture independent library. Usually the library files are installed on /usr/local/lib/gv.

Administrators may want to modify this file in order to set up gv according to the local needs of their system.

a user specific resource file.
The name of this file is either ~/.gv or as described by the XUSERFILESEARCHPATH environment variable.

The files gv_user.ad and gv_system.ad (located in the library directory of gv, which is most probably either /usr/local/lib/gv/ or /usr/lib/gv/) may serve as a basis for constructing the user and system specific resource files.

Note that the user and system specific resource files are not the only sources of preferences taken into account when gv is started. However, in practice these are the most important.


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3.2 Resources of gv

The following describes some of the resources of gv. The precise syntax of some of the resource values may be inferred from the appended default system specific resource file.

antialias
Whether antialiasing should be used. Valid values are True and False.

It defaults to True.

autoCenter
Whether the displayed page should automatically be centered (for instance when opening a new file). Valid values are True and False.

It defaults to True.

autoResize
Whether gv is allowed to resize the main window according to the size of the current page. Valid values are True and False.

It defaults to True.

confirmPrint
Whether printing requires an extra confirmation. Valid values are True and False.

It defaults to True.

confirmQuit
Whether leaving gv requires extra confirmation. Valid values are 0 (Never), 1 (When processing) and 2 (Always). The default value is 1, which causes a confirmation request when trying to leave gv in the presence of pending PDF to Postscript conversions.
scrollingEyeGuide
If this resource is True scrolling via the keyboard causes a temporary border to be drawn around the previously visible area of the page. Allowed values are True and False.

It defaults to True.

infoVerbose
Defines the behavior of the info popup which shows messages from ghostscript. Valid values are Silent (Never), Errors (show only errror messages) and All (Any message is being shown).

It defaults to Errors.

xinerama
Defines whether the display resolution is determined by xinerama. Valid values are On (use Xinerama if available), Off (do not use Xinerama) and Auto (heuristically decide whether to use Xinerama or not).

It defaults to Auto.

ignoreEOF
Defines the behaviour of the postscript scanner as described in the Options section. Valid values are True and False.

It defaults to True.

respectDSC
Determines whether gv should attempt to respect document structuring comments. Valid values are True and False.

It defaults to True.

reverseScrolling
Defines the interpretation of directions when scrolling with the mouse. Valid values are True and False.

It defaults to False.

swapLandscape
Whether the meaning of landscape and seacape should be interchanged. Valid values are True and False.

It defaults to False.

scratchDir
Specifies a directory used to store temporary data.

It defaults to the invocation directory.

defaultSaveDir
Specifies the default destination directory for files to be saved.

It defaults to the home directory, ~/.

useBackingPixmap
If the value of this resource is False the X Server is advised that saving off-screen pixels of the displayed page would be beneficial (maintaining backing store). In this case gv does not actively maintain the contents of the page but relies on the X Server. The server is, however, always free to stop maintaining backing backing store. If the value of this resource is True the X Server is advised that maintaining backing store is not useful. In this case gv attempts to allocate a sufficiently large pixmap to store the contents of the displayed page.

It defaults to True.

watchFile
Whether the document should be checked periodically and updated automatically if changes are detected. Valid values are True and False.

It defaults to False.

watchFileFrequency
Defines the time in milliseconds elapsing between successive checks of the document when watchFile is set to True. Allowed values must be larger than 500.

It defaults to 1000.

printCommand
The command used for printing a file. The command may contain multiple %s wildcards which will be replaced by the name of the file to be printed.

It defaults to lpr.

saveposFilename
This file is used for saving positions by the z and u keys.

It defaults to ~/gv.savepos.

gsInterpreter
The command used to start the ghostscript interpreter.

It defaults to gv.

gsCmdScanPDF
The command used to extract document structuring comments from a PDF file.

It defaults to gs -dNODISPLAY -dQUIET -sPDFname=%s -sDSCname=%s pdf2dsc.ps -c quit

gsCmdConvPDF
The command used to convert a PDF file to PostScript.

It defaults to gs -dNODISPLAY -dQUIET -dNOPAUSE -sPSFile=%s %s -c quit

gsX11Device
The ghostscript command line option which activates the X11 device.

It defaults to -sDEVICE=x11

gsX11AlphaDevice
The ghostscript command line option which activates the X11 device with antialiasing enabled.

It defaults to -dNOPLATFONTS -sDEVICE=x11alpha

gsSafer
Determines whether ghostscript should be started with the -dSAFER command line option.

It defaults to True.

gsQuiet
Determines whether ghostscript should be started with the -dQUIET command line option.

It defaults to True.

gsArguments
May be used to provide additional command line options for the ghostscript interpreter. Starting gv with the -arguments arguments option will override this resource setting.

It defaults to the empty string.

magMenu
Describes the menu that pops up when preparing to to zoom an area of the displayed page.
dirs
Defines a list of directories accessible via the Directories menu in the file selection window. The special value Home corresponds to the users home directory, the value Tmp corresponds to the scratch directory as defined by the scratchDir resource.

It defaults to Home Tmp /usr/doc /usr/local/doc

filter
Defines the default filter to be used when displaying a directory contents in the file selection window. A filter is specified according to the syntax
     
        <filter>    := [<filespecs>] [no <filespecs>]
        <filespecs> := <filespec> [<filespecs>]
        <filespec>  := filename possibly including wildcards '*'
                       which match any character.

Example: The filter

     
        GV*filter: *.ps *.pdf no .*

screens out all files with names starting with a dot and keeps of the remaining ones only those which end on .ps or .pdf.

It defaults to no .*

filters
Defines a list of filters offered in the Filters menu of the file selection window. The filter None has a special meaning causing all files to be displayed when the corresponding menu entry is selected.
miscMenuEntries
Describes the menu that pops up when clicking with the third mouse button on the displayed page. The value of this resource is a list of menu entries.

Allowed entries are


titleStyle
Whether the name of the displayed document should be shown in the title bar of the window. The name of gv's icon will also change accordingly if this resource is set to True.

If this is 0, no title will be shown. 1 means to show a the document title or the file name if there is no document title. Only the file name is shown with 2.

It defaults to 1.

maximumWidth, maximumHeight
When resizing gv will not attempt to exceed the size specified by these resources. These resources may be specified as a positive integer or as screen, optionally combined with a positive or negative offset. The default values listed above provide examples for this syntax. screen will automatically be replaced by the size of the screen.

maximumWidth defaults to screen-20. maximumHeight defaults to screen-44.

minimumWidth, minimumHeight
Defines a minimum size for the main window. Valid values for both resources are positive integers larger than 200.

minimumWidth defaults to 400. minimumHeight defaults to 430.

scale
Sets the initial scale. The value of this resource is the offset of the scale to be selected relative to the scale 1.0 in the the Scale menu.

It defaults to 0.

scaleBase
Selects the initial scale base. The value of this resource should be a positive integer.

It defaults to 1.

scales
Defines the available scales bases and scales in the Scale menu.
orientation
Sets the initial orientation. Valid values are

automatic causes gv to attempt to derive the correct orientation from document structuring comments.

It defaults to automatic.

fallbackOrientation
Defines the paper-size to be used when automatic orientation detetction fails. Valid values are portrait, landscape, seascape and upside-down.

It defaults to portrait.

medias
A list describing the page medias known to gv. List entries starting with ! or # will not appear in the Media menu but will still be used for automatic paper size detection.
pageMedia
Sets the paper size. Allowd values are as given in the above list of paper-sizes. Specifying automatic causes gv to attempt to derive the correct paper-size from document structuring comments.

It defaults to automatic.

fallbackPageMedia
Defines the paper-size to be used when automatic paper-size detetction fails. Valid values are as given in the above list of paper-sizes.

It defaults to a4.


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4 Mouse and key bindings


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4.1 Mouse bindings in the Main and the Zoom window

The following mouse events are defined when the mouse pointer is either on the displayed page or on a zoomed area:

press button 1, move mouse, release button 1
Scrolls the displayed page 'proportionally'.
press button 3, move mouse, release button 3
Scrolls the displayed page 'absolutely'.
double-click with button 1
In the main window this displays the previous/next page if the double-click occured in the left/right half of the window. In a zoom window it does nothing.
press button 2, release button 2
Pops up a small menu which allows to choose a magnification for a certain area around the current mouse position. After selecting a magnification a zoom window pops up displaying the area at the chosen scale.
press button 2, move mouse, release button 2
This draws and thereby defines a rectangular region which can be displayed in a zoom window. The magnification for the area can be selected by means of a popup menu which appears after releasing button 2.
press button 1, press button 2
Reload the current page. This event sequence works only in the main window.
press button 3, release button 3
Pops up a small menu which offers a few standard actions like 'Reload', 'Mark Page', etc.


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4.2 Mouse bindings in the File Selection popup

The following mouse events are defined when the mouse pointer is in the window of either a file or a directory list:

press button 1, move mouse, release button 1
Scrolls a file or directory list 'proportionally'.
press button 2, move mouse, release button 2
Scrolls a file or directory list 'absolutely'.
press button 2, release button 2
Scrolls a file or directory list one page up/down if the button was pressed in the upper/lower half of the list.
double-click with button 1 on a filename
Selects the file and closes the File Selection popup.
click with button 1 on a directory name
Causes the contents of this directory to be displayed.


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4.3 Mouse bindings in the Table of Contents

The following mouse events are defined when the mouse pointer is in the window showing a list of page numbers of the current file (table of contents):

press button 1, move mouse, release button 1
Scrolls the table of contents.
press button 1 on a page number
Go to this page.
press button 2 on a page number
Mark this page if it is unmarked, but unmark it if it is marked.
press button 2, move mouse, release button 2
Marks/unmarks all unmarked/marked pages in the region crossed by the mouse pointer during the movement.


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4.4 Mouse bindings in the Panner widget

The Panner widget is the rectangular region located close to the left edge of the main window. It indicates the size and the position of the visible area of the current page relative to the total page.

The following mouse events are defined when the mouse pointer is in this region:

press button 1, move mouse
Scrolls the displayed page.
press button 2
Display the previous page.
press button 3
Display the next page.


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4.5 Mouse bindings in the << and >> button windows

The << and >> buttons are used to move to another page. The following mouse events are defined:

press button 1
Move 1 page forward/backwards.
press button 2
Move 5 pages forward/backwards.
press button 3
Move 10 pages forward/backwards.


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4.6 Key Bindings

The following key events are defined in the main window. Those bindings scrolling the page are also defined in zoom popups.


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4.6.1 Notation

<S-X>
means press <Shift> and key <X>
<C-X>
means press <Ctrl> and key <X>
<SC-X>
means press <Shift> or <Ctrl> and key <X>


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4.6.2 Miscellaneous keys:

<A>
Toggle antialiasing on and off
<O>
Open a new file
<Q>
Quit gv
<R>
Toggle gv's resizing behaviour
<I>
Respect/Ignore document structuring
<W>
Watch file / Don't watch file
<S>
Save the marked pages
<SC-S>
Save the current file
<P>
Print the marked pages
<C-P>
Print the current file
<S-P>
Switches to presentation mode by forking a new GNU gv process.
<c-L>
Reload the current page
<.>
Reload the current page
<SC-.>
Reopen the current file
<M>
Mark the current page
<N>
Unmark the current page
<Z>
append the current coordinate to a file whose name is given by the GV.saveposFilename resource.
<U>
enter a command with the current coordinate as its default parameter. By defalt it is % TODO \PutAtPos(x,y)(), where x,y are the current coordinate and the user can put needed commands into (). This command is appended to a file whose name is given by the GV.saveposFilename resource.


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4.6.3 Orientation

<7>
Orientation portrait
<8>
Orientation landscape
<9>
Orientation upside-down
<0>
Orientation seascape


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4.6.4 Magnification

<SC-6>
Select the scale entry -6 relative to the scale 1.0
<SC-5>
Select the scale entry -5 relative to the scale 1.0
<SC-4>
Select the scale entry -4 relative to the scale 1.0
<SC-3>
Select the scale entry -3 relative to the scale 1.0
<SC-2>
Select the scale entry -2 relative to the scale 1.0
<SC-1>
Select the scale entry -1 relative to the scale 1.0
<^>
Select the scale 1.0 (for german keyboard layout)
<`>
Select the scale 1.0
<1>
Select the scale entry 1 relative to the scale 1.0
<2>
Select the scale entry 2 relative to the scale 1.0
<3>
Select the scale entry 3 relative to the scale 1.0
<4>
Select the scale entry 4 relative to the scale 1.0
<5>
Select the scale entry 5 relative to the scale 1.0
<6>
Select the scale entry 6 relative to the scale 1.0
<+>
Select the next scale entry
<=>
Select the next scale entry
<->
Select the previous scale entry


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4.6.5 Navigating

<Arrow>
Scroll in the direction of the arrow
<S-Up>
Scroll columns up or jump -1 pages
<S-Down>
Scroll columns down or jump 1 pages
<S-Left>
Scroll rows left or jump -1 pages
<S-Right>
Scroll rows right or jump 1 pages
<C-Up>
Jump -1 pages (to top/left corner)
<C-Down>
Jump 1 pages (to top/left corner)
<C-Left>
Jump -5 pages (to top/left corner)
<C-Right>
Jump 5 pages (to top/left corner)
<D>
Identical to arrow up
<X>
Identical to arrow down
<Z>
Identical to arrow left
<Y>
Identical to arrow left
<C>
Identical to arrow right
<V>
Center the page
<SC-Space>
Scroll columns up or jump -1 pages
<Space>
Scroll columns down or jump 1 pages
<BackSpace>
Scroll columns up or jump -1 pages
<Insert>
Jump -5 pages
<Delete>
Jump 5 pages
<Home>
Go to the first page
<End>
Go to the last page
<Prior>
Jump -1 pages
<Next>
Jump 1 pages
<Keypad 0-9>
Highlight a page number
<Keypad ->
Highlight previous page number
<Keypad +>
Highlight next page number
<Keypad Enter>
Jump to the highlighted page
<C-Enter>
Scroll columns up
<S-Enter>
Scroll columns up
<Enter>
Scroll columns down
<B>
Jump -1 pages
<F>
Jump 1 pages


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5 Comments about the user interface


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5.1 Scales

The Scale menu which allows to view the document at different sizes is divided into two parts. The first part shows a list of available scale bases, the second part, separated by a line, lists the relative scales which are applied with respect to the selected scale base.

By default two scales bases are available, the Natural size and the Pixel based base. When choosing the Pixel based scale base a relative scale of 1.0 causes one postscript point to correspond to one pixel on the screen.

When viewing a document at a relative scale of 1.0 using the Natural size base the page should appear in its real size, as if printed on paper. For the Natural size base to work properly gv has to know the correct size of the root window. Automatic detection of this size unfortunately only provides approximate results, therefore it is best if it is provided by the user. To do so the resource

   GV.screenSize:  <width> x <height>

should be added to the SCREEN_RESOURCES property of the screen the document is viewed on, with width and height describing the width and height of the root window in units of millimeters. For instance by using the command

   echo "GV.screenSize: 396 x 291" | xrdb -override -screen

a width of 346 mm and a height of 291 mm will be used for the Natural size scale base. Alternatively the resource

   GV.screenSize_<machine>_<disp>_<scr>:  <width> x <height>

may be added to a resource file read by gv. Here machine ,disp and ANGLED describe the display on which gv displays the document. For instance, if the display is set to tic.tac.toe.wo:0.1 the resource should be specified as

   GV.screenSize_tic_0_1: 396 x 291

Note that this method doesn't work on VMS. As a last alternative the resource

   GV.screenSize:  <width> x <height>

may be added to one of the resource files. However, for obvious reasons this method should be used only on single user machines.


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5.2 Scrolling

It is probably a de facto standard for user interfaces that windows are supposed to be scrolled by means of scrollbars attached to their sides. However, for various reasons the use of scrollbars has been minimized in gv.

Instead, in all windows with obscured data, scrolling may be performed by

pressing button1, moving the mouse, then releasing button1

directly in the window. This includes the displayed page, zoom popups, the table of contents and the file and directory lists displayed in the file selection popup.


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5.3 Displaying new versions of a document

During document creation it is usually desirable to always display the newest version of the document in work.

Instead of explicitly loading it via the file selection popup the most recent version can be displayed by pressing the Reload button in the main window. Choosing the Reload entry in the menu that pops up when clicking with the third mouse button anywhere on the displayed page certainly has the same effect.

More comfortable is the "Watch File" feature which may be switched on by selecting the corresponding entry in the State menu. If activated gv will check every now and then if a new version of the displayed file exists. If so it will be displayed automatically. By default the file is checked about once every second.

Finally it may also be left to the document creating program to trigger gv to update its display. To do so the program should send the SIGHUP signal to gv. For instance at the end of a shell script generating a postscript file from latex sources the line

   kill -SIGHUP <gv_pid>

may be added (here gv_pid is the process id of gv). Executing the script and thereby creating a new version of the document will then also cause the result to be displayed instantaneously. Please note that this feature is available only on X11 R6 based systems.


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6 Frequently asked questions


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6.1 What happened to the scroll bars?

They have been removed in order to make more room for the image. The displayed portion of the image may be moved by dragging the image or the paner (panel between the "Save Marked" and << >> buttons) with the mouse. Alternatively, the cursor arrow keys can be used.


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6.2 How can I make even more room for the image?

Use the "spartan" style by starting gv with the command

         gv --spartan

This removes the "Open", "Print", "Save", "Reload", and page marking buttons (they are still available from the "File" and "Page" menus) and replaces them with the document attribute controls, which are normally along the top.


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6.3 Small characters are not very clear

Antialiasing can improve the display of bitmapped fonts (eg. from TeX) when displayed on a colour or greyscale screen. The same technique is used by xdvi. Note that antialiasing requires at least Ghostscript version 4.x.

Antialiasing can be turned on from the "State" menu, and can be made default by saving the setting in State | gv Options....


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6.4 The output is not refreshed automatically

There are two methods that can be used to save the contents of the window when it's not currently displayed: backing store and backing pixmap. Some X-servers seem to support only backing store (eg. VAXstations) and some only backing pixmap (eg. some X-terminals, including EWS).

In order to force gv to use one method or the other, use the State | Setup Options ... menu and toggle the "Backing Pixmap" button. When selected/highlighted (normally the default), gv will use backing pixmap; otherwise it will use backing store. Select "Apply" to use a new setting and "Save" to make it the new default.


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7 gv internals


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7.1 Interface with ghostscript


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7.1.1 Ghostview interface to ghostscript

When the GHOSTVIEW environment variable is set, ghostscript draws on an existing drawable rather than creating its own window. Ghostscript can be directed to draw on either a window or a pixmap.


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7.1.2 Drawing on a Window

The GHOSTVIEW environment variable contains the window id of the target window. The window id is an integer. Ghostscript will use the attributes of the window to obtain the width, height, colormap, screen, and visual of the window. The remainder of the information is gotten from the GHOSTVIEW property on that window.


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7.1.3 Drawing on a Pixmap

The GHOSTVIEW environment variable contains a window id and a pixmap id. They are integers separated by white space. Ghostscript will use the attributes of the window to obtain the colormap, screen, and visual to use. The width and height will be obtained from the pixmap. The remainder of the information, is gotten from the GHOSTVIEW property on the window. In this case, the property is deleted when read.


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7.1.4 The GHOSTVIEW environment variable

parameters
window-id [pixmap-id]
scanf format
"%d %d"

Explanation of parameters:

window-id
tells ghostscript where to If pixmap-id is not present, ghostscript will draw on this window.
pixmap-id
If present, tells ghostscript that a pixmap will be used as the final destination for drawing. The window will not be touched for drawing purposes.


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7.1.5 The GHOSTVIEW property

type
STRING
parameters
bpixmap orient llx lly urx ury xdpi ydpi [left bottom top right]
scanf format
"%d %d %d %d %d %d %f %f %d %d %d %d"

Explanation of parameters:

pixmap
pixmap id of the backing pixmap for the window. If no pixmap is to be used, this parameter should be zero. This parameter must be zero when drawing on a pixmap.
orient
orientation of the page. The number represents clockwise rotation of the paper in degrees. Permitted values are 0, 90, 180, 270.
llx, lly, urx, ury
Bounding box of the drawable. The bounding box is specified in PostScript points in default user coordinates.
xdpi, ydpi
Resolution of window. (This can be derived from the other parameters, but not without roundoff error. These values are included to avoid this error.)
left, bottom, top, right (optional)
Margins around the window. The margins extend the imageable area beyond the boundaries of the window. This is primarily used for popup zoom windows. I have encountered several instances of PostScript programs that position themselves with respect to the imageable area. The margins are specified in PostScript points. If omitted, the margins are assumed to be 0.


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7.1.6 Events from ghostscript

If the final destination is a pixmap, the client will get a property notify event when ghostscript reads the GHOSTVIEW property causing it to be deleted.

Ghostscript sends events to the window where it read the GHOSTVIEW property. These events are of type ClientMessage. The message_type is set to either PAGE or DONE. The first long data value gives the window to be used to send replies to ghostscript. The second long data value gives the primary drawable. If rendering to a pixmap, it is the primary drawable. If rendering to a window, the backing pixmap is the primary drawable. If no backing pixmap is employed, then the window is the primary drawable. This field is necessary to distinguish multiple ghostscripts rendering to separate pixmaps where the GHOSTVIEW property was placed on the same window.

The PAGE message indicates that a "page" has completed. Ghostscript will wait until it receives a ClientMessage whose message_type is NEXT before continuing.

The DONE message indicates that ghostscript has finished processing.


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7.2 Comments recognized by ghostview

%!PS-Adobe-<real> [EPSF-<real>]
%%BoundingBox: <int> <int> <int> <int>|(atend)
%%CreationDate: <textline>
%%Orientation: Portrait|Landscape|(atend)
%%Pages: <uint>|(atend)
%%PageOrder: Ascend|Descend|Special|(atend)
%%Title: <textline>
%%DocumentMedia: <text> <real> <real> <real> <text> <text>
%%DocumentPageSizes: <text>
%%EndComments

Preview section:

%%BeginPreview
%%EndPreview

Defaults section:

%%BeginDefaults
%%PageBoundingBox: <int> <int> <int> <int>|(atend)
%%PageOrientation: Portrait|Landscape
%%PageMedia: <text>
%%EndDefaults

Prolog section:

%%BeginProlog
%%EndProlog

Setup section:

%%BeginSetup
%%PageBoundingBox: <int> <int> <int> <int>|(atend)
%%PageOrientation: Portrait|Landscape
%%PaperSize: <text>
%%EndSetup

Page properties:

%%Page: <text> <uint>
%%PageBoundingBox: <int> <int> <int> <int>|(atend)
%%PageOrientation: Portrait|Landscape
%%PageMedia: <text>
%%PaperSize: <text>
%%Trailer
%%EOF

Document section:

%%BeginDocument: <text> [<real>[<text>]]
%%EndDocument

Binary section:

%%BeginBinary: <uint>
%%EndBinary

Data section:

%%BeginData: <uint> [Hex|Binary|ASCII[Bytes|Lines]]
%%EndData


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7.3 Paper Keywords and paper size in points

Letter		 612x792
LetterSmall	 612x792
Tabloid		 792x1224
Ledger		1224x792
Legal		 612x1008
Statement	 396x612
Executive	 540x720
A0               2384x3371
A1              1685x2384
A2		1190x1684
A3		 842x1190
A4		 595x842
A4Small		 595x842
A5		 420x595
B4		 729x1032
B5		 516x729
Envelope	 ???x???
Folio		 612x936
Quarto		 610x780
10x14		 720x1008


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Appendix A GNU General Public License

Version 3, 29 June 2007
     Copyright © 2007 Free Software Foundation, Inc. http://fsf.org/
     
     Everyone is permitted to copy and distribute verbatim copies of this
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Preamble

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When we speak of free software, we are referring to freedom, not price. Our General Public Licenses are designed to make sure that you have the freedom to distribute copies of free software (and charge for them if you wish), that you receive source code or can get it if you want it, that you can change the software or use pieces of it in new free programs, and that you know you can do these things.

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For example, if you distribute copies of such a program, whether gratis or for a fee, you must pass on to the recipients the same freedoms that you received. You must make sure that they, too, receive or can get the source code. And you must show them these terms so they know their rights.

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    The Free Software Foundation may publish revised and/or new versions of the GNU General Public License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns.

    Each version is given a distinguishing version number. If the Program specifies that a certain numbered version of the GNU General Public License “or any later version” applies to it, you have the option of following the terms and conditions either of that numbered version or of any later version published by the Free Software Foundation. If the Program does not specify a version number of the GNU General Public License, you may choose any version ever published by the Free Software Foundation.

    If the Program specifies that a proxy can decide which future versions of the GNU General Public License can be used, that proxy's public statement of acceptance of a version permanently authorizes you to choose that version for the Program.

    Later license versions may give you additional or different permissions. However, no additional obligations are imposed on any author or copyright holder as a result of your choosing to follow a later version.

  16. Disclaimer of Warranty.

    THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM “AS IS” WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.

  17. Limitation of Liability.

    IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

  18. Interpretation of Sections 15 and 16.

    If the disclaimer of warranty and limitation of liability provided above cannot be given local legal effect according to their terms, reviewing courts shall apply local law that most closely approximates an absolute waiver of all civil liability in connection with the Program, unless a warranty or assumption of liability accompanies a copy of the Program in return for a fee.

END OF TERMS AND CONDITIONS

How to Apply These Terms to Your New Programs

If you develop a new program, and you want it to be of the greatest possible use to the public, the best way to achieve this is to make it free software which everyone can redistribute and change under these terms.

To do so, attach the following notices to the program. It is safest to attach them to the start of each source file to most effectively state the exclusion of warranty; and each file should have at least the “copyright” line and a pointer to where the full notice is found.

     one line to give the program's name and a brief idea of what it does.
     Copyright (C) year name of author
     
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
     the Free Software Foundation, either version 3 of the License, or (at
     your option) any later version.
     
     This program is distributed in the hope that it will be useful, but
     WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     General Public License for more details.
     
     You should have received a copy of the GNU General Public License
     along with this program.  If not, see http://www.gnu.org/licenses/.

Also add information on how to contact you by electronic and paper mail.

If the program does terminal interaction, make it output a short notice like this when it starts in an interactive mode:

     program Copyright (C) year name of author
     This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
     This is free software, and you are welcome to redistribute it
     under certain conditions; type `show c' for details.

The hypothetical commands `show w' and `show c' should show the appropriate parts of the General Public License. Of course, your program's commands might be different; for a GUI interface, you would use an “about box”.

You should also get your employer (if you work as a programmer) or school, if any, to sign a “copyright disclaimer” for the program, if necessary. For more information on this, and how to apply and follow the GNU GPL, see http://www.gnu.org/licenses/.

The GNU General Public License does not permit incorporating your program into proprietary programs. If your program is a subroutine library, you may consider it more useful to permit linking proprietary applications with the library. If this is what you want to do, use the GNU Lesser General Public License instead of this License. But first, please read http://www.gnu.org/philosophy/why-not-lgpl.html.