zgv.texi

zgv-5.6,一个Linux系统下的图片浏览器(VGA/SVGA)

\input texinfo   @c -*-texinfo-*-
@c %**start of header
@setfilename zgv
@settitle The zgv manual
@setchapternewpage odd
@c %**end of header

@c To make an Info file from this, do `make info'.
@c To make a DVI file from this (usually for printing), do `make dvi'.

@set VERSION 5.6
@set UPDATED 5th May 2002

@c Most categories seem to suffer from being too specific, making them
@c effectively useless; hopefully this one is at least nicely generic.
@c This is `ifinfo' to stop texi2{html,roff} seeing it, as they don't
@c handle it.
@ifinfo
@dircategory Graphics Utilities
@direntry
* zgv: (zgv).   A picture viewer for Linux systems with VGA/SVGA.
@end direntry
@end ifinfo

@c Some notes on the use of indexes here:
@c - The keystroke index is used for keys, but called the `keyboard
@c   commands index'.
@c - The variable index is used for config file entries, as that's
@c   pretty much what they are.


@c Texinfo's way of handling copyright messages is, to say the least,
@c bloody awful. You have to have the whole lot twice. (I'm not sure I can
@c think of a better way, but that's not the point. :-))

@ifinfo
The zgv manual, for version @value{VERSION}, last updated
@value{UPDATED}.

Copyright 1998-2001 Russell Marks.

Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
preserved on all copies.

@ignore
Permission is granted to process this file through TeX and print the
results, provided the printed document carries a copying permission
notice identical to this one except for the removal of this paragraph
(this paragraph not being relevant to the printed manual).

@end ignore
Permission is granted to copy and distribute modified versions of this
manual under the conditions for verbatim copying, provided that the
entire resulting derived work is distributed under the terms of a
permission notice identical to this one.

Permission is granted to copy and distribute translations of this manual
into another language, under the above conditions for modified versions,
except that this permission notice may be stated in a translation
approved by the Free Software Foundation.
@end ifinfo

@titlepage
@title zgv
@subtitle A picture viewer for Linux systems with VGA displays
@subtitle version @value{VERSION}
@author Russell Marks

@c The following two commands start the copyright page.
@page
@vskip 0pt plus 1filll
Copyright @copyright{} 1998-2001 Russell Marks.

Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
preserved on all copies.

Permission is granted to copy and distribute modified versions of this
manual under the conditions for verbatim copying, provided that the
entire resulting derived work is distributed under the terms of a
permission notice identical to this one.

Permission is granted to copy and distribute translations of this manual
into another language, under the above conditions for modified versions,
except that this permission notice may be stated in a translation
approved by the Free Software Foundation.

@end titlepage

@ifinfo
@node    Top, Overview, (dir), (dir)
@top The zgv manual

zgv is a full-featured picture viewer, with a reasonably nice file
selector, for Linux systems with VGA/SVGA (it uses svgalib). It can read
most common file formats (and, it might be suggested, a few others
besides).

By default zgv only takes input from the keyboard. @xref{Using a Mouse},
for how to enable extensive mouse support.

This documentation is for zgv version @value{VERSION}, last updated
@value{UPDATED}.

@menu
* Overview::                    A simple look at how to use zgv.
* Acknowledgements::            Who did what.

* Invoking zgv::                Command-line options.

* Online help::                 Getting help on what keys to press.
* The File Selector::           How to pick files to view, and more.
* The Viewer::                  What you can do when a picture is onscreen.

* xzgv Compatibility::          xzgv is similar to zgv, but not
                                identical; you can make zgv behave a bit
                                more like xzgv, helpful if you use both.

* File Formats::                Issues related to the way picture files
                                  are stored.
* Consoles::                    How zgv deals with virtual consoles, and
                                  console switching.

* Using a Mouse::               How to enable a mouse and use it in zgv.

* Configuring zgv::             You can change aspects of zgv's behaviour.

* Rationale::                   The thinking behind certain things.
* Bugs and Restrictions::       Problems with zgv, and how to report bugs.
* Future Changes::              Pending ideas for zgv features etc.

 --- Indexes ---

* Keyboard Commands Index::     What various keys do in zgv.
* Configuration Variables Index::  Settings in zgv's config file(s).
* Concept Index::               General index of topics covered.
@end menu

@end ifinfo


@node  Overview, Acknowledgements, Top, Top
@comment  node-name,  next,  previous,  up
@chapter Overview

@cindex introduction to zgv
@cindex overview

zgv lets you view pictures on Linux boxes with VGA/SVGA displays. The
kinds of pictures it supports are raster-format pictures (sometimes
called `bitmaps' and/or `pixmaps'); things like GIF files, JPEG files,
PNG files, and so on. (The full list of file formats supported is listed
elsewhere. @xref{Supported File Formats}.)

Most of the time, you will probably want to use zgv's file selector
(@pxref{The File Selector}) to pick which file(s) to view. This is what
appears when you start zgv as just @code{zgv} (@pxref{Invoking zgv}). It
displays a list of subdirectories and picture files in the current
directory, along with small `thumbnail' versions of the pictures if they
exist. (If no thumbnails appear for a given directory, or if they are
missing for some files, you can create/update them by pressing @kbd{u}.
@xref{Updating Thumbnails}.)

When you've picked a file to view, you can view it by pressing
@kbd{Enter}. This puts you into the viewer, where the whole screen is
used to display the picture (@pxref{The Viewer}). You can then move
around the picture (if it is larger than the screen) using the cursor
keys. Pressing @kbd{Esc} returns you to the file selector, where you can
pick another file to view, or you can quit zgv by pressing @kbd{Esc}
again.

While zgv is by default controlled entirely from the keyboard, it does
have quite good mouse support you can enable if you like that sort of
thing. @xref{Using a Mouse}.

This overview is, as you might expect, only the very simplest of
introductions to what zgv can do, and describes only a very basic use of
zgv. zgv can do a lot more; read on to find out what.


@node  Acknowledgements, Invoking zgv, Overview, Top
@comment  node-name,  next,  previous,  up
@chapter Acknowledgements

@cindex acknowledgements
@cindex credits

@c first, direct (or direct-ish :-)) zgv contributions:

zgv was primarily written by Russell Marks, who also wrote this manual.

@c The rest are (mostly) alphabetically ordered by surname; my precedent for
@c this was the Emacs info file, but I've seen it used in other places
@c too, and it seems a sensible approach anyway.
@c 
@c I couldn't help thinking this was terribly unfair on Matan
@c though - what with him contributing more than anyone else (well,
@c except me of course) - so I've deliberately broken the order to put
@c his name first. :-)

Matan Ziv-Av added multiple-image animated GIF support, Photo-CD
support, brightness/contrast support in high-colour modes, the original
file-rename code, and some of the support for 32-bit modes, as well as
inspiring a few other changes like high-res file selector support.

Carsten Engelmann wrote the BMP support.

Edwin Fong added support for command-line slideshows, and a few other
features including the original mouse support.

Costa Sapuntzakis contributed code for much faster JPEG thumbnail
generation.

@c this isn't really `direct', but I think it belongs here.
@code{install-info} is a (very) slightly modified version of the
original (which is part of the @code{texinfo} package). This program is
used during installation. I think it was mostly written by Karl Berry,
but it's not terribly clear.

@c now libraries etc.:

The authors of the special-purpose libraries zgv uses deserve credit ---
JPEG and PNG might not have been supported in zgv without the JPEG
library, libpng and zlib. Most of all though, zgv would certainly not
have been written without VGAlib and later svgalib, and thanks are due
to Tommy Frandsen, Harm Hanemaayer, Michael Weller, Matan Ziv-Av and
many others for that.

Thanks also to the zgv users who've contributed bug reports,
suggestions, ideas for features, and even@dots{} dare I say@dots{}
compliments. zgv would be even worse without their input, so count your
lucky stars. :-)

This program is based in part on the work of the Independent JPEG
Group.

``The Graphics Interchange Format(c) is the Copyright property of
CompuServe Incorporated. GIF(sm) is a Service Mark property of
CompuServe Incorporated.''


@node  Invoking zgv, Online help, Acknowledgements, Top
@comment  node-name,  next,  previous,  up
@chapter Invoking zgv

@cindex invoking zgv
@cindex starting zgv
@cindex running zgv
@cindex command-line options
@cindex options, command-line
@cindex arguments, command-line
@c NB: no `command-line args' since you'll see `command-line options' if
@c you look for that.

@c some for `zgv file', `zgv dir'
@cindex starting on given directory
@cindex directory, starting on given
@cindex viewing only one file
@cindex file, viewing only one
@cindex picture, viewing only one

@c for -m
@cindex mode, specifying the initial video
@cindex video mode, specifying the initial
@cindex changing the initial video mode
@cindex default video mode

@c XXX probably want others...

Normally you'd invoke zgv as plain @code{zgv}. However, you can directly
specify files to view or a start directory on the command-line. In
addition, there are various options.

(If you're new to zgv, you should probably skip the rest of this section
for now and come back to it later.)

The general format of the zgv command-line goes roughly like this:

@example
zgv [@var{options}] [@var{start-dir} | @var{file} [@var{file2} ...]]
@end example

Two types of options are supported --- the traditional Unix
single-letter options, and GNU-style long options. Both forms are listed
in the table below, but not all long options have single-letter
equivalents.

Note that all options are processed after any configuration file(s).
Config file settings are just like the long-option names below minus the
@code{--} (@pxref{Configuring zgv}), though a few command-line options
are not permitted as config file settings (e.g. @code{help}), and vice
versa.

Here's what the options do:

@table @code
@item -A
@vindex auto-animate
@itemx --auto-animate
Automatically animate multiple-image GIF files (@pxref{Multiple-image
GIF Animation}). This limits your viewing options greatly, but can be
handy for slideshows and the like.

@vindex auto-mode-fit
@item --auto-mode-fit
Automatically switch modes to suit image size.

@item -p
@vindex avoid-single-progress
@itemx --avoid-single-progress
Don't show progress indicator when loading a single file from the
command-line.

@vindex black-background
@item --black-background
Try to use a black (or nearest-to-black) background when in 8-bit modes.
This can be quite nice for consistency's sake when viewing (say) a
mixture of GIFs and JPEGs, but the extra pass over the loaded image
slows things down slightly.

@item -b
@vindex block-cursor
@itemx --block-cursor
Use a blocky outline cursor in the selector, which is rather unsubtle
but more obvious.

@vindex brightness
@item --brightness @var{adjust_val}
Specify how much to add to colour values to change brightness (default
0). Values less than zero decrease brightness, values greater than zero
increase it. Brightness is applied after contrast by default.

@vindex centre
@vindex center
@item --centre
@itemx --center
(Normally enabled, use e.g. @code{--centre=off} to disable.) By default
zgv centres pictures smaller than the screen, in whichever dimensions
they are smaller. This setting gives you a way to disable this, so that
pictures always start in the top-left.
			
@vindex clear-screen-on-exit
@item --clear-screen-on-exit
Clear the screen on exit. (Normally, zgv leaves the original screen
contents intact.)

@vindex col-black
@item --col-black @var{r g b}
Set colour used for `black' (text) in selector; RGB values should be in
the range 0-63 for this and the other colour settings below, and the
three numbers should be quoted, e.g. @code{--col-black "10 20 30"}.

@vindex col-dark
@item --col-dark @var{r g b}
Set colour used for lowlights in selector.

@vindex col-light
@item --col-light @var{r g b}
Set colour used for highlights in selector.

@vindex col-medium
@item --col-medium @var{r g b}
Set colour used for background in selector.

@vindex col-tagged
@item --col-tagged @var{r g b}
Set colour used for tagged files in selector.

@vindex contrast
@item --contrast @var{multiplier}
Specify how much to multiply colour values by to change contrast
(default 1.0). zgv multiplies each colour's difference from grey by this
number; values less than one decrease contrast, values greater than one
increase it. Negative values are also allowed, and act in a similar way,
but with the picture's colours inverted. Contrast is applied before
brightness by default.