eog/doc/C/eog.sgml

<!DOCTYPE book PUBLIC "-//GNOME//DTD DocBook PNG Variant V1.1//EN"[
  <!ENTITY eog "<application>Eye of GNOME</application>">
  <!ENTITY appver "2.9">
  <!ENTITY manver "0.2">
]>

<book id="index"> <!-- please do not change the id -->

  <bookinfo>
    <title>&eog; User's Guide</title>

    <authorgroup>
      <author>
	<firstname>Eliot</firstname>
	<surname>Landrum</surname>
	<affiliation>
	  <address><email>eliot@landrum.cx</email></address>
	</affiliation>
      </author>

      <author>
	<firstname>Federico</firstname>
	<surname>Mena Quintero</surname>
	<affiliation>
	  <address><email>federico@gnu.org</email></address>
	</affiliation>
      </author>
    </authorgroup>

    <copyright>
      <year>2000</year>
      <holder>Eliot Landrum</holder>
    </copyright>

    <copyright>
      <year>2000</year>
      <holder>The Free Software Foundation</holder>
    </copyright>

<!-- Translators: uncomment this:
    <copyright>
      <year>2000</year>
      <holder>ME-THE-TRANSLATOR (Latin translation)</holder>
    </copyright>
-->

    <legalnotice>
      <para>
	Permission is granted to copy, distribute and/or modify this
	document under the terms of the <citetitle>GNU Free
	Documentation License</citetitle>, Version 1.1 or any later
	version published by the Free Software Foundation with no
	Invariant Sections, no Front-Cover Texts, and no Back-Cover
	Texts. You may obtain a copy of the <citetitle>GNU Free
	Documentation License</citetitle> from the Free Software
	Foundation by visiting <ulink type="http"
	url="http://www.fsf.org">their Web site</ulink> or by writing
	to:

	<address>
	  The Free Software Foundation, Inc.,
	  <street>59 Temple Place</street> - Suite 330,
	  <city>Boston</city>, <state>MA</state> <postcode>02111-1307</postcode>,
	  <country>USA</country>
	</address>
      </para>

      <para>
	Many of the names used by companies to distinguish their
	products and services are claimed as trademarks. Where those
	names appear in any GNOME documentation, and those trademarks
	are made aware to the members of the GNOME Documentation
	Project, the names have been printed in caps or initial caps.
      </para>
    </legalnotice>

    <releaseinfo>
      This is version &manver; of the &eog; manual.
    </releaseinfo>
  </bookinfo>

  <!-- Introduction -->

  <chapter id="intro">
    <title>Introduction</title>

    <para>
      &eog; is a program for viewing images and managing collections
      of images.  It does proper handling of large images, say,
      scanned posters at full resolution.  It supports full opacity or
      alpha channel information.  &eog; can zoom and scroll large
      images quickly while keeping memory usage constant.
    </para>

    <para>
      The functionality to work as a program for managing collections
      of images is not yet implemented as of version &appver;, but it
      is planned for the future.  The goal is for &eog; to become a
      useful tool for photographers and other people who have to
      maintain large collections of images in an organized fashion.
      <footnote>
	<para>
	  This includes collectors of
	  <literal>alt.binaries.pictures.furniture</literal>.
	</para>
      </footnote>
    </para>

    <!-- Acknowledgements -->

    <sect1 id="acknowledgements">
      <title>Acknowledgements</title>

      <para>
	&eog; was written by <author><firstname>Federico</firstname>
	<surname>Mena Quintero</surname></author>
	<email>federico@gnu.org</email>.
      </para>

      <para>
	<author><firstname>Arik</firstname>
	<surname>Devens</surname></author>
	<email>arik@helixcode.com</email> wrote the code for setting
	the configuration options.
      </para>

      <para>
	<author><firstname>Eliot</firstname>
	<surname>Landrum</surname></author>
	<email>eliot@landrum.cx</email> wrote the first version of
	this manual.
      </para>

      <para>
	<author><firstname>Damien</firstname>
	<surname>Diederen</surname></author>
	<email>dash@linuxbe.org</email> wrote the original fast
	scaling code that was the inspiration for &eog;.
      </para>

      <para>
	<author><firstname>Mark</firstname>
	<surname>Crichton</surname></author>
	<email>crichton@gimp.org</email> wrote the initial versions of
	the <application>gdk-pixbuf</application> library, and bravely
	maintained the <application>Imlib</application> library for
	<acronym>GNOME</acronym>'s purposes.  He also rode many of us
	in the famous minivan of death.
      </para>

      <para>
	<author><firstname>Tuomas</firstname>
	<surname>Kuosmanen</surname></author>
	<email>tigert@gimp.org</email> created the cute icon for
	&eog;, as well as lots of nice artwork.  That artwork was
	proudly viewed in &eog; as well.
      </para>

      <para>
	<author><firstname>Raph</firstname>
	<surname>Levien</surname></author>
	<email>raph@gimp.org</email> wrote the
	<application>libart</application> library, microtile arrays,
	<application>GdkRGB</application>, and some awesome code for
	doing imaging <emphasis>fast</emphasis>.  He also provided a
	bottomless pit of knowledge.
      </para>

      <para>
	<author><firstname>Michael</firstname>
	<surname>Meeks</surname></author>
	<email>mmeeks@gnu.org</email> wrote the initial
	<application>Bonobo</application> component for &eog;, and
	provided good feedback all along.
      </para>

      <para>
	<author><firstname>Maciej</firstname>
	<surname>Stachowiak</surname></author>
	<email>mjs@eazel.com</email>, all-around super hacker,
	provided excellent feedback for &eog;.
      </para>

      <para>
	<author><firstname>Owen</firstname>
	<surname>Taylor</surname></author>
	<email>otaylor@redhat.com</email> wrote the awesome scaling
	and compositing functions for
	<application>gdk-pixbuf</application>.  He also provided a
	really bottomless pit of knowledge.
      </para>

      <para>
	<author><firstname>Carsten</firstname> <othername>&ldquo;The
	Rasterman&rdquo;</othername>
	<surname>Haitzler</surname></author>
	<email>raster@rasterman.com</email> provided many interesting
	discussions about classification of images and other imaging
	stuff.  He also throws the best parties.
      </para>

      <para>
	The <acronym>GNOME</acronym> translation team let us use &eog;
	in a zillion twisty languages, all different.
      </para>

<!-- Translations: uncomment this:
      <para>
	The Latin translation was done by ME <email>MYNAME@MYADDRESS</email>.  
	Please send all comments and suggestions regarding this
	translation to SOMEWHERE.
      </para>
-->
    </sect1>
  </chapter>

  <!-- Basic Usage -->

  <chapter id="basic-usage">
    <title>Basic Usage</title>

    <para>
      This chapter tells you how to use &eog; as a basic image viewer.
      It describes how to run the program and view images, the main
      menu options, and the full screen viewing mode.
    </para>

    <!-- Running EOG -->

    <sect1 id="running-eog">
      <title>Running &eog;</title>

      <para>
	To run &eog;, select
	<menuchoice><guisubmenu>Graphics</guisubmenu> <guimenuitem>Image 
	Viewer</guimenuitem></menuchoice> from the <guimenu>Main
	Menu</guimenu>, or type <command>eog</command> on the command
	line.
      </para>

      <para>
	You can specify an arbitrary number of image file names in the
	command line as well, for example <command>eog foo.jpg
	bar.png</command>.  &eog; will open each image in a separate
	window.
      </para>
    </sect1>

    <!-- Image Windows -->

    <sect1 id="image-windows">
      <title>Image Windows</title>

      <para>
	Starting &eog; opens an <interface>image window</interface>,
	shown in <xref linkend="figure-image-window">.

	<figure id="figure-image-window">
	  <title>Image window</title>
	  <screenshot>
	    <screeninfo>Image window</screeninfo>
	    <graphic fileref="fig/image-window" format="png" srccredit="Eliot Landrum"></graphic>
	  </screenshot>
	</figure>
      </para>

      <para>
	To load an image into the <interface>image window</interface>,
	simply click the <guibutton>Open</guibutton> button on the
	main toolbar.  A standard file dialog will then open to allow
	you to select an image file.  &eog; will automatically detect
	the type of image being opened.
      </para>
	
      <para>
	You can also open images by dragging them from another program
	and dropping them into an <interface>image window</interface>.
	For example, you can select a number of image files in the
	file manager and drag them to &eog;.
      </para>

      <para>
	&eog; supports the following image file formats:

	<itemizedlist>
	  <listitem>
	    <para>
	      <acronym>BMP</acronym> (Windows Bitmap)
	    </para>
	  </listitem>

	  <listitem>
	    <para>
	      <acronym>GIF</acronym> (Graphics Interchange Format)
	    </para>
	  </listitem>

	  <listitem>
	    <para>
	      <acronym>ICB</acronym> (Truevision Targa image)
	    </para>
	  </listitem>

	  <listitem>
	    <para>
	      <acronym>ICO</acronym> (Windows Icon)
	    </para>
	  </listitem>

	  <listitem>
	    <para>
	      <acronym>JPEG</acronym> (Joint Photographic Experts Group)
	    </para>
	  </listitem>

	  <listitem>
	    <para>
	      <acronym>PNG</acronym> (Portable Network Graphics)
	    </para>
	  </listitem>

	  <listitem>
	    <para>
	      <acronym>PNM</acronym> (Portable Anymap from the PPM Toolkit)
	    </para>
	  </listitem>

	  <listitem>
	    <para>
	      <acronym>RAS</acronym> (Sun Raster file)
	    </para>
	  </listitem>

	  <listitem>
	    <para>
	      <acronym>T<>FF</acronym> (Tagged Image File Format)
	    </para>
	  </listitem>

	  <listitem>
	    <para>
	      <acronym>XPM</acronym> (X Pixmap)
	    </para>
	  </listitem>
	</itemizedlist>>
      </para>

      <note>
	<title>Opening Unrecognized Formats</title>

	<para>
	  If the file you select is of a type that &eog; does not
	  recognize, a dialog will appear to warn you that &eog; was
	  unable to process the selected file.  On a side note, the
	  type of a file can be found using the Unix
	  <command>file</command> command.
	</para>
      </note>

      <para>
	After an image is loaded into the viewer, you can make use of
	the buttons in the toolbar, shown in <xref
	linkend="figure-image-window-toolbar">:

	<figure id="figure-image-window-toolbar">
	  <title>Image Window Toolbar</title>
	  <screenshot>
	    <screeninfo>Image Window Toolbar</screeninfo>
	    <graphic fileref="fig/image-window-toolbar" format="png" srccredit="Eliot Landrum"></graphic>
	  </screenshot>
	</figure>

	<variablelist>
	  <varlistentry>
	    <term><guibutton>Open</guibutton></term>
	    <listitem>
	      <para>
		Opens a new image.  Depending on the preferences
		settings, the new image will substitute the current
		image in the window or a new window will be created
		for it.
	      </para>
	    </listitem>
	  </varlistentry>

	  <varlistentry>
	    <term><guibutton>Close</guibutton></term>
	    <listitem>
	      <para>
		Closes the corresponding image window.  If this is the
		last open window, the program will exit.
	      </para>
	    </listitem>
	  </varlistentry>

	  <varlistentry>
	    <term><guibutton>In</guibutton></term>
	    <listitem>
	      <para>
		Zooms into the image, that is, it makes the image
		appear larger.
	      </para>
	    </listitem>
	  </varlistentry>

	  <varlistentry>
	    <term><guibutton>Out</guibutton></term>
	    <listitem>
	      <para>
		Zooms out of the image, that is, it makes the image
		appear smaller.
	      </para>
	    </listitem>
	  </varlistentry>

	  <varlistentry>
	    <term><guibutton>1:1</guibutton></term>
	    <listitem>
	      <para>
		Sets the zoom factor to 1:1, that is, pixels on the
		screen will match the pixels on the original image.
	      </para>
	    </listitem>
	  </varlistentry>

	  <varlistentry>
	    <term><guibutton>Fit</guibutton></term>
	    <listitem>
	      <para>
		Resizes the image so that it fills the image window.
	      </para>
	    </listitem>
	  </varlistentry>
	</variablelist>
      </para>

      <!-- Zooming and scrolling -->

      <sect2 id="zooming-and-scrolling">
	<title>Zooming and Scrolling</title>

	<para>
	  One of the main features of &eog; as an image viewer is that
	  it lets you view very large images easily.  You can do this
	  by changing the zoom factor at which images are displayed
	  and by scrolling around the area of an image.
	</para>

	<para>
	  &eog; lets you change the zoom factor of an image in several
	  ways:

	  <itemizedlist>
	    <listitem>
	      <para>
		If you have a wheel mouse, you can simply use the
		wheel to quickly adjust the zoom factor.
	      </para>
	    </listitem>

	    <listitem>
	      <para>
		You can use the toolbar buttons as shown in <xref
		linkend="figure-image-window-toolbar">.
	      </para>
	    </listitem>

	    <listitem>
	      <para>
		You can press the <keycap>+</keycap> (plus) and
		<keycap>-</keycap> (minus) keys to increase and
		decrease the zoom factor, respectively.
	      </para>

	      <note>
		<para>
		  This only works on U.S. keyboards for now.  If you
		  know how to fix the code to support other keyboard
		  layouts, please email Federico at
		  <email>federico@gnu.org</email>.
		</para>
	      </note>
	    </listitem>

	    <listitem>
	      <para>
		You can press <keycap>1</keycap> to set the zoom
		factor to 1:1, or you can press <keycap>F</keycap> to
		fit the image to the window size.
	      </para>
	    </listitem>

	    <listitem>
	      <para>
		You can use the zooming commands in the
		<guimenu>View</guimenu> menu.
	      </para>
	    </listitem>
	  </itemizedlist>
	</para>

	<para>
	  In addition, you can use the <guibutton>1:1</guibutton> or
	  <guibutton>Fit</guibutton> buttons in the toolbar to go back
	  to the original image's size or to make it fill the window,
	  respectively.
	</para>

	<para>
	  If an image is zoomed so that it does not fit in the window,
	  you can scroll it in several ways:

	  <itemizedlist>
	    <listitem>
	      <para>
		You can simply click on the image and drag it around.
	      </para>
	    </listitem>

	    <listitem>
	      <para>
		You can use the scrollbars with the mouse.
	      </para>
	    </listitem>

	    <listitem>
	      <para>
		You can use the arrow keys to pan the image.
	      </para>
	    </listitem>
	  </itemizedlist>
	</para>

	<para>
	  A wheel mouse is the most convenient way to navigate around
	  a large image, since you can zoom and drag the image using
	  only the mouse.  If you prefer the keyboard, you can use it
	  without having to use the mouse as well.
	</para>
      </sect2>

      <!-- Menu Bar Commands -->

      <sect2 id="menu-bar-commands">
	<title>Menu Bar Commands</title>

	<para>
	  The menu bar located at the top of image windows provides
	  the following commands.
	</para>

	<variablelist>

	  <!-- File menu -->

	  <varlistentry>
	    <term><guimenu>File</guimenu></term>
	    <listitem>
	      <formalpara>
		<title>
		  <menuchoice>
		    <guimenuitem>Create New Window</guimenuitem>
		  </menuchoice>
		</title>

		<para>
		  Creates a new, empty image window.  You can open any
		  number of windows and load images into them.
		</para>
	      </formalpara>

	      <formalpara>
		<title>
		  <menuchoice>
		    <shortcut>
		      <keycombo>
			<keycap>Ctrl</keycap>
			<keycap>O</keycap>
		      </keycombo>
		    </shortcut>
		    <guimenuitem>Open Image...</guimenuitem>
		  </menuchoice>
		</title>

		<para>
		  Lets you select an image using a standard file
		  dialog, opens the image.
		</para>
	      </formalpara>

	      <formalpara>
		<title>
		  <menuchoice>
		    <shortcut>
		      <keycombo>
			<keycap>Ctrl</keycap>
			<keycap>W</keycap>
		      </keycombo>
		    </shortcut>
		    <guimenuitem>Close This Window</guimenuitem>
		  </menuchoice>
		</title>

		<para>
		  Closes the corresponding image window.  If this is
		  the last open window, the program will exit.
		</para>
	      </formalpara>

	      <formalpara>
		<title>
		  <menuchoice>
		    <shortcut>
		      <keycombo>
			<keycap>Ctrl</keycap>
			<keycap>Q</keycap>
		      </keycombo>
		    </shortcut>
		    <guimenuitem>Exit</guimenuitem>
		  </menuchoice>
		</title>

		<para>
		  This lets you stop viewing images and go back to go
		  doing more productive stuff.
		</para>
	      </formalpara>
	    </listitem>
	  </varlistentry>

	  <!-- View menu -->

	  <varlistentry>
	    <term><guimenu>View</guimenu></term>
	    <listitem>
	      <formalpara>
		<title>
		  <menuchoice>
		    <shortcut>
		      <keycap>+</keycap>
		    </shortcut>
		    <guimenuitem>Zoom In</guimenuitem>
		  </menuchoice>
		</title>

		<para>
		  Zooms into the image.
		</para>
	      </formalpara>

	      <formalpara>
		<title>
		  <menuchoice>
		    <shortcut>
		      <keycap>-</keycap>
		    </shortcut>
		    <guimenuitem>Zoom Out</guimenuitem>
		  </menuchoice>
		</title>

		<para>
		  Zooms away from the image.
		</para>
	      </formalpara>

	      <formalpara>
		<title>
		  <menuchoice>
		    <shortcut>
		      <keycap>1</keycap>
		    </shortcut>
		    <guimenuitem>Zoom 1:1</guimenuitem>
		  </menuchoice>
		</title>

		<para>
		  Sets the zoom factor to 1:1; pixels on the screen
		  will match the pixels in the original image.
		</para>
	      </formalpara>

	      <formalpara>
		<title>
		  <menuchoice>
		    <guisubmenu>Zoom factor</guisubmenu>
		  </menuchoice>
		</title>

		<para>
		  Provides a number of common zoom factors for you to
		  pick.
		</para>
	      </formalpara>

	      <formalpara>
		<title>
		  <menuchoice>
		    <shortcut>
		      <keycap>F</keycap>
		    </shortcut>
		    <guimenuitem>Fit to Window</guimenuitem>
		  </menuchoice>
		</title>

		<para>
		  Resizes the image so that it fills the image window.
		</para>
	      </formalpara>

	      <formalpara>
		<title>
		  <menuchoice>
		    <shortcut>
		      <keycap>S</keycap>
		    </shortcut>
		    <guimenuitem>Full Screen</guimenuitem>
		  </menuchoice>
		</title>

		<para>
		  Opens a full screen viewer for the image.
		</para>
	      </formalpara>
	    </listitem>
	  </varlistentry>

	  <!-- Settings menu -->

	  <varlistentry>
	    <term><guimenu>Settings</guimenu></term>
	    <listitem>
	      <formalpara>
		<title>
		  <menuchoice>
		    <guimenuitem>Preferences...</guimenuitem>
		  </menuchoice>
		</title>

		<para>
		  Opens the preferences dialog where you can set the
		  configuration options for &eog;.
		</para>
	      </formalpara>
	    </listitem>
	  </varlistentry>

	  <!-- Help menu -->

	  <varlistentry>
	    <term><guimenu>Help</guimenu></term>
	    <listitem>
	      <formalpara>
		<title>
		  <menuchoice>
		    <guimenuitem>About...</guimenuitem>
		  </menuchoice>
		</title>

		<para>
		  Shows basic information about &eog;.
		</para>
	      </formalpara>
	    </listitem>
	  </varlistentry>
	</variablelist>
      </sect2>
    </sect1>

    <!-- Full Screen View -->

    <sect1 id="full-screen-view">
      <title>Full Screen View</title>

      <para>
	&eog; lets you use the whole screen of your computer to view
	images.  This can be useful for large images or for when you
	don't want any visual distractions.  You can make an image be
	displayed on the whole screen by selecting the
	<menuchoice><guimenu>View</guimenu> <guimenuitem>Full
	Screen</guimenuitem></menuchoice> command.
      </para>

      <para>
	To navigate around the image, the full screen view accepts the
	same keyboard shortcuts and mouse actions as normal image
	windows.
      </para>

      <para>
	To exit the full screen view, simply press the
	<keycap>Escape</keycap> key or <keycombo>
	<keycap>Ctrl</keycap> <keycap>W</keycap></keycombo>.
      </para>
    </sect1>
  </chapter>

  <!-- Configuring EOG -->

  <chapter id="configuring-eog">
    <title>Configuring &eog;</title>

    <para>
      You can set the configuration options for &eog; by using the
      <interface>Preferences</interface> dialog.  You can access it
      with the <menuchoice> <guimenu>Settings</guimenu>
      <guimenuitem>Preferences...</guimenuitem> </menuchoice> command
      on the main menu.  This chapter describes the different options
      that you can set.
    </para>

    <!-- Display Preferences -->

    <sect1 id="prefs-display">
      <title>Display Preferences</title>

      <para>
	The first page of the <interface>Preferences</interface>
	dialog is for the display configuration; it is shown in <xref
	linkend="figure-prefs-display">.

	<figure id="figure-prefs-display">
	  <title>Display Preferences</title>
	  <screenshot>
	    <screeninfo>Display Preferences</screeninfo>
	    <graphic fileref="fig/prefs-display" format="png" srccredit="Arik Devens"></graphic>
	  </screenshot>
	</figure>
      </para>

      <variablelist>

	<!-- Interpolation Type -->

	<varlistentry>
	  <term>Interpolation type</term>
	  <listitem>
	    <para>
	      This option lets you set the interpolation method that
	      &eog; will use when scaling images.  When zooming into
	      an image you can choose to look at the big rectangular
	      pixels or to look at a smoothed-out version; when
	      zooming out you can look at a low-quality version of the
	      image or at a higher-quality rendering.
	    </para>

	    <para>
	      Normally you want to leave interpolation turned on,
	      because most photographic images look better that way.
	      You may want to turn it off if you are zooming into very
	      low-resolution computer images such as icons.
	    </para>

	    <formalpara>
	      <title>Nearest neighbor</title>

	      <para>
		This means use no interpolation.  Pixels will be
		replicated for zooming in and you will see fat
		rectangles.  When zooming down, the image will lose a
		lot of detail and possibly look odd.
	      </para>
	    </formalpara>

	    <formalpara>
	      <title>Bilinear</title>

	      <para>
		This a simple and very fast interpolation method.
		When zooming in, up to four adjacent pixels will be
		taken into account to compute the color of a new
		pixel.  When zooming out, regions of the original
		image will be averaged together to compute the colors
		of the new pixels.
	      </para>
	    </formalpara>

	    <formalpara>
	      <title>Hyperbolic</title>

	      <para>
		This is the highest-quality and slowest interpolation
		method.  It does interpolation as described by
		<author><firstname>George</firstname>
		<surname>Wolberg</surname> </author> in
		<citetitle>Digital Image Warping</citetitle>.
	      </para>
	    </formalpara>
	  </listitem>
	</varlistentry>

	<!-- Transparency type -->

	<varlistentry>
	  <term>Transparency type</term>

	  <listitem>
	    <para>
	      This tells &eog; how to render the background for images
	      that have partially opaque regions.  It is customary to
	      overlay the image on a checkerboard so that you can
	      clearly see which areas are partially opaque or fully
	      transparent.  However, you may also want to overlay the
	      image over a solid background so that you can see it
	      without any visual distractions.
	    </para>

	    <formalpara>
	      <title>Dark checks</title>

	      <para>
		Makes checks consisting of alternating black and dark
		gray squares.
	      </para>
	    </formalpara>

	    <formalpara>
	      <title>Midtone checks</title>

	      <para>
		Makes checks consisting of alternating dark and light
		gray squares.
	      </para>
	    </formalpara>

	    <formalpara>
	      <title>Light checks</title>

	      <para>
		Makes checks consisting of alternating light gray and
		white squares.
	      </para>
	    </formalpara>

	    <formalpara>
	      <title>Black only / Gray only / White only</title>

	      <para>
		These options create a solid-colored background for
		the image.
	      </para>
	    </formalpara>
	  </listitem>
	</varlistentry>

	<!-- Check size -->

	<varlistentry>
	  <term>Check size</term>

	  <listitem>
	    <para>
	      This option specifies the size of the checks used as a
	      background for images that have partially opaque
	      regions.  This is mostly a matter of personal preference
	      or gratuitous configurability, depending on the way you
	      see it.
	    </para>
	  </listitem>
	</varlistentry>

	<!-- Dither type -->

	<varlistentry>
	  <term>Dither type</term>

	  <listitem>
	    <para>
	      This option specifies which dithering method to use.  In
	      &eog; dithering consists of simulating more colors than
	      your display can actually handle by clustering together
	      pixels of different colors in the hope that your brain
	      will do its thing and blend them together.  You may want
	      to turn on dithering if you are seeing color banding in
	      your images instead of smooth color transitions in the
	      shaded areas of your images.
	    </para>

	    <formalpara>
	      <title>None</title>

	      <para>
		This specifies no dithering, so &eog; will make every
		pixel be the closest color to the one in the original
		image.
	      </para>
	    </formalpara>

	    <formalpara>
	      <title>Normal (pseudocolor)</title>

	      <para>
		With this option set, dithering will only be performed
		on pseudocolor displays.  These are displays that use
		a limited palette of colors to display images, such as
		cheap or old video hardware with only 256 simultaneous
		colors.  If you have such a thing, well, you should
		really get a better display.  You have no idea of what
		you are missing.
	      </para>
	    </formalpara>

	    <formalpara>
	      <title>Maximum (high color)</title>

	      <para>
		This will perform dithering even on high color
		displays, even though they have a pretty good quality
		even without dithering.  High color displays are
		present in medium-end video hardware or many laptops
		that can display 65,536 simultaneous colors.

		<footnote>
		  <para>
		    Some even cheaper hardware can display only 32,768
		    colors.  To make sure, you just have to count
		    them.
		  </para>
		</footnote>

		This will make high-color displays be almost
		indistinguishable from a true color display (true
		color displays are the ones with millions of
		simultaneous colors.  If you are really neurotic and
		are dying to know, the exact number is 16,777,216).
	      </para>
	    </formalpara>
	  </listitem>
	</varlistentry>

	<!-- Two-pass scrolling -->

	<varlistentry>
	  <term>Two-pass scrolling</term>

	  <listitem>
	    <para>
	      &eog; has a nifty feature that can make scrolling look
	      faster when it really is not.  It can do this by drawing
	      the images in two steps:  the first step renders a
	      low-quality version of the image very quickly, and the
	      second step does a full-quality render.  The idea is
	      that you will get better visual continuity even though
	      the program cannot keep up with your obsessively-fast
	      scrolling; you will see the low-quality version almost
	      instantaneously and the high-quality version will
	      magically appear over the quick version.
	    </para>

	    <para>
	      Some people think this is annoying, though, and they may
	      want to turn this option off.  They are the kind of
	      people that balk at the though of eating curried
	      tuna fish and other delicate and subtle things in life.
	      Still, we have to cater to them, so we do.
	    </para>
	  </listitem>
	</varlistentry>
      </variablelist>
    </sect1>

    <!-- Viewer Preferences -->

    <sect1 id="prefs-viewers">
      <title>Viewer Preferences</title>

      <para>
	The second page of the <interface>Preferences</interface>
	dialog is for the configuration of the different image viewing
	modes; it is shown in <xref linkend="figure-prefs-viewers">.

	<figure id="figure-prefs-viewers">
	  <title>Viewer Preferences</title>
	  <screenshot>
	    <screeninfo>Viewer Preferences</screeninfo>
	    <graphic fileref="fig/prefs-viewers" format="png" srccredit="Arik Devens"></graphic>
	  </screenshot>
	</figure>
      </para>

      <para>
	This page of the <interface>Preferences</interface> dialog is
	divided into two parts.  The first one specifies the options
	for image windows, and the second one specifies the options
	for the full screen viewing mode.
      </para>

      <!-- Options for Image Windows -->

      <variablelist>
	<title>Options for Image Windows</title>

	<!-- Use scrollbars -->

	<varlistentry>
	  <term>Use scrollbars</term>

	  <listitem>
	    <para>
	      This option specifies when to display scrollbars.  Some
	      people find them distracting and prefer to scroll the
	      image by using only the keyboard or by dragging the
	      image directly with the mouse.
	    </para>

	    <formalpara>
	      <title>Never</title>

	      <para>
		Guess what?  This specifies that scrollbars should
		never be displayed.
	      </para>
	    </formalpara>

	    <formalpara>
	      <title>Only if image does not fit</title>

	      <para>
		Scrollbars will not be displayed if the image is
		zoomed to be smaller than the display area.  If it
		doesn't fit, the scrollbars will automatically pop up
		for your perusal.
	      </para>
	    </formalpara>
	  </listitem>
	</varlistentry>

	<!-- Pick window size and zoom factor automatically -->

	<varlistentry>
	  <term>Pick window size and zoom factor automatically</term>

	  <listitem>
	    <para>
	      When you open an image, it is convenient to have &eog;
	      automatically pick the size of the window based on the
	      image size.  If the image is small then it makes sense
	      to make the window just as big as it needs to be to fit
	      the image.  If the image is too big, then it is
	      convenient to have &eog; automatically scale it down to
	      a reasonable size so that it will fit inside a window on
	      the screen.
	    </para>

	    <para>
	      In general you should turn this option off only if the
	      thought of resizing your windows every five seconds
	      excites you very greatly.
	    </para>
	  </listitem>
	</varlistentry>

	<!-- Open images in a new window -->

	<varlistentry>
	  <term>Open images in a new window</term>

	  <listitem>
	    <para>
	      When opening an image, &eog; will normally substitute
	      the current image of a window with the new image that it
	      just opened.  You may prefer it to create a new image
	      window and open the new image there instead.
	    </para>
	  </listitem>
	</varlistentry>
      </variablelist>

      <!-- Options for the Full Screen View -->

      <variablelist>
	<title>Options for the Full Screen View</title>

	<!-- Use scrollbars -->

	<varlistentry>
	  <term>Use scrollbars</term>

	  <listitem>
	    <para>
	      This option has the same function as the one for image
	      windows.
	    </para>
	  </listitem>
	</varlistentry>

	<!-- Use 1:1 zoom factor -->

	<varlistentry>
	  <term>Use 1:1 zoom factor</term>

	  <listitem>
	    <para>
	      This will cause the full screen view to use a zoom
	      factor of 1:1 when it is initially opened.
	    </para>
	  </listitem>
	</varlistentry>

	<!-- Use same zoom factor as image window -->

	<varlistentry>
	  <term>Use same zoom factor as image window</term>

	  <listitem>
	    <para>
	      This will cause the full screen view to use the same
	      zoom factor that the image window was using.  This gives
	      you the effect of just switching to a bigger viewport.
	    </para>
	  </listitem>
	</varlistentry>

	<!-- Fit all images to screen -->

	<varlistentry>
	  <term>Fit all images to screen</term>

	  <listitem>
	    <para>
	      This makes the full screen view scale all images so that
	      they will fill the whole screen.
	    </para>
	  </listitem>
	</varlistentry>

	<!-- Fit standard-sized images to screen -->

	<varlistentry>
	  <term>Fit standard-sized images to screen</term>

	  <listitem>
	    <para>
	      Sometimes you may want to use the aforementioned options
	      to start the full screen view at 1:1 zoom or with the
	      same zoom factor as the image window, yet you may want
	      images with sizes like 640&times;480 or 1024&times;768
	      to automatically fill the whole screen.  These sizes are
	      &ldquo;standard&rdquo; in that they represent common
	      monitor resolutions, i.e. images at that size were
	      designed to be viewed using the whole screen.  When you
	      turn this switch on, &eog; will scale images with
	      similar well-known sizes to the size of the whole screen
	      regardless of the setting of the full screen zooming
	      options.
	    </para>
	  </listitem>
	</varlistentry>

	<!-- Put a bevel around the edge of the screen -->

	<varlistentry>
	  <term>Put a bevel around the edge of the screen</term>
	  <listitem>
	    <para>
	      Some people like to have a well-defined border at the
	      edge of the screen instead of fading into the eternal
	      and unfathomable pitch-blackness of the monitor's edges.
	    </para>

	    <para>
	      Other people like the author have buggy X servers that
	      cause incorrect results when scrolling stuff near the
	      edge of the screen.
	    </para>

	    <para>
	      In any case, turning this option on will cause &eog; to
	      draw a 3D bevel at the edge of the screen instead of
	      using the whole screen for your image.
	    </para>
	  </listitem>
	</varlistentry>
      </variablelist>
    </sect1>
  </chapter>

  <!-- Providing Feedback for EOG -->

  <appendix id="providing-feedback">
    <title>Providing Feedback for &eog;</title>

    <para>
      Please send all comments, suggestions, and bug reports to the
      <ulink url="http://bugs.gnome.org" type="http">GNOME bug
      tracking database</ulink>.  (Instructions for submitting bug
      reports can be found <ulink
      url="http://bugs.gnome.org/Reporting.html" type="http">
      on-line</ulink>.)  You can also use the <application>Bug Report
      Tool</application> (<command>bug-buddy</command>), available in
      the <guisubmenu>Utilities</guisubmenu> submenu of <guimenu>Main
      Menu</guimenu>, for submitting bug reports.
    </para>

    <para>
      Please send all comments and suggestions regarding this manual
      to the <ulink type="http"
      url="http://developer.gnome.org/projects/gdp">GNOME
      Documentation Project</ulink> by sending an email to
      <email>docs@gnome.org</email>.  You can also add your comments
      online by using the <ulink type="http"
      url="http://www.gnome.org/gdp/doctable/">GNOME Documentation
      Status Table</ulink>.
    </para>
  </appendix>

  <!-- License -->

  <appendix id="license">
    <title>License</title>
	
    <para>
      This program is free software; you can redistribute it and/or
      modify it under the terms of the <citetitle>GNU General Public
      License</citetitle> as published by the Free Software
      Foundation; either version 2 of the License, or (at your option)
      any later version.
    </para>

    <para>
      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
      <citetitle>GNU General Public License</citetitle> for more
      details.
    </para>

    <para>
      A copy of the <citetitle>GNU General Public License</citetitle>
      is included as an appendix to the <citetitle>GNOME Users
      Guide</citetitle>.  You may also obtain a copy of the
      <citetitle>GNU General Public License</citetitle> from the Free
      Software Foundation by visiting <ulink type="http"
      url="http://www.fsf.org">their Web site</ulink> or by writing to

      <address>
	Free Software Foundation, Inc.
	<street>59 Temple Place</street> - Suite 330
	<city>Boston</city>, <state>MA</state> <postcode>02111-1307</postcode>
	<country>USA</country>
      </address>
    </para>
  </appendix>
</book>