Warning, /games/palapeli/doc/index.docbook is written in an unsupported language. File is not indexed.

 <?xml version="1.0" ?>
 <!DOCTYPE book PUBLIC "-//KDE//DTD DocBook XML V4.5-Based Variant V1.1//EN" "dtd/kdedbx45.dtd" [
 <!ENTITY i18n-psc "<application>Palapeli Slicer Collection</application>">
 <!ENTITY % English "INCLUDE">
 <!ENTITY % addindex "IGNORE">
 ]>
 
 <book id="palapeli" lang="&language;">
   <bookinfo>
     <title>The &palapeli; Handbook</title>
     <authorgroup>
       <author>
         <firstname>Johannes</firstname>
         <surname>L&#xF6;hnert</surname>
         <affiliation><address><email>loehnert_kde@gmx.de</email></address></affiliation>
       </author>
       <author>
         <firstname>Stefan</firstname>
         <surname>Majewsky</surname>
         <affiliation><address><email>majewsky@gmx.net</email></address></affiliation>
       </author>
       <author>
         <firstname>Ian</firstname>
         <surname>Wadham</surname>
         <affiliation><address><email>iandw.au@gmail.com</email></address></affiliation>
       </author>
       <!-- TRANS:ROLES_OF_TRANSLATORS -->
     </authorgroup>
 
     <copyright>
       <year>2009, 2010</year>
       <holder>Johannes L&#xF6;hnert, Stefan Majewsky</holder>
     </copyright>
     <copyright>
       <year>2014</year>
       <holder>Ian Wadham</holder>
     </copyright>
     <legalnotice>&FDLNotice;</legalnotice>
     <date>2021-10-06</date>
     <releaseinfo>2.1 (KDE Gear 21.08)</releaseinfo>
 
     <abstract>
       <para>This is the manual for &palapeli;, a jigsaw puzzle game.</para>
     </abstract>
     <keywordset>
       <keyword>KDE</keyword>
       <keyword>kdegames</keyword>
       <keyword>game</keyword>
       <keyword>puzzle game</keyword>
       <keyword>jigsaw puzzle</keyword>
       <keyword>Palapeli</keyword>
     </keywordset>
   </bookinfo>
 
   <chapter id="introduction">
     <title>Introduction</title>
     <para>&palapeli; is a single-player jigsaw puzzle game. With it you can create and play puzzles ranging from 4 to 10,000 pieces. This version includes facilities to assist in solving large puzzles (300 pieces or more) within the size limits of a computer screen.</para>
     <para>The main &palapeli; window is separated into two areas, the puzzle collection and the puzzle table.</para>
     <para>This manual continues by describing those two areas.</para>
   </chapter>
 
   <chapter id="collection">
     <title>Browsing the puzzle collection</title>
     <sect1 id="play-maintain-collection">
       <title>Playing puzzles and updating the collection</title>
     <para>When you launch &palapeli; for the first time, your puzzle collection already contains some sample puzzles that come with &palapeli;. Click on one of them to start playing immediately. Later, when you have created some of your own puzzles (see below), you can also click on them to start playing.</para>
     <para>Play takes place on the puzzle table; see <link linkend="puzzletable">the section after next</link> for how to use the puzzle table.</para>
     <note><para>You can select and highlight puzzles in the puzzle list by hold the &Ctrl; key and click with the &LMB;. Pressing the &LMB; or &RMB; without the &Ctrl; key opens that puzzle for playing in the puzzle table.</para>
     <para>On &macOS; you need to double-click with the &LMB; to begin playing. A single click will just select and highlight one entry in the puzzle list.</para></note>
     <para>As well as playing a puzzle, you can use the puzzle collection for the following actions:</para>
     <itemizedlist>
       <listitem><para><emphasis>create</emphasis> new puzzles from images on your disk</para></listitem>
       <listitem><para><emphasis>import</emphasis> puzzles made by others</para></listitem>
       <listitem><para><emphasis>export</emphasis> puzzles to share them with your friends and the world</para></listitem>
       <listitem><para><emphasis>delete</emphasis> puzzles you do not need any more</para></listitem>
     </itemizedlist>
     <para>The following section shows how to perform these tasks with the action icons in the toolbar.</para>
       </sect1>
     <sect1 id="toolbar-collection">
       <title>Toolbar overview</title>
       <variablelist>
         <varlistentry>
           <term><inlinemediaobject><imageobject><imagedata fileref="tools-wizard.png" format="PNG"/></imageobject></inlinemediaobject> <guiicon>Create New Puzzle...</guiicon></term>
           <listitem>
             <para><action>Opens a dialog which allows you to create a puzzle from an image on your disk.</action> See <link linkend="create-puzzles">the next chapter</link> for details.</para>
           </listitem>
         </varlistentry>
         <varlistentry>
           <term><inlinemediaobject><imageobject><imagedata fileref="edit-delete.png" format="PNG"/></imageobject></inlinemediaobject> <guiicon>Delete Puzzle</guiicon></term>
           <listitem><para><action>Any puzzles that you have selected in the puzzle list, will be permanently deleted from your collection. </action></para><warning><para>This action cannot be undone.</para></warning></listitem>
         </varlistentry>
         <varlistentry>
           <term><inlinemediaobject><imageobject><imagedata fileref="document-import.png" format="PNG"/></imageobject></inlinemediaobject> <guiicon>Import from File...</guiicon></term>
           <listitem><para><action>When you have received a &palapeli; puzzle file (which can usually be recognized by the file extension <literal role="extension">.puzzle</literal>), you can use this action to import it into your local collection.</action> Puzzle files can also be played by simply clicking on them in the file manager of your choice, but after the import, the puzzle will appear in your local collection, and you can safely delete the downloaded puzzle file.</para></listitem>
         </varlistentry>
         <varlistentry>
           <term><inlinemediaobject><imageobject><imagedata fileref="document-export.png" format="PNG"/></imageobject></inlinemediaobject> <guiicon>Export to File...</guiicon></term>
           <listitem><para><action>This will export the currently selected puzzles to files, in order to enable you to give them to your friends, publish them on the web, or make backup copies of your collection.</action></para></listitem>
         </varlistentry>
       </variablelist>
     </sect1>
   </chapter>
 
   <chapter id="create-puzzles">
     <title>Creating new puzzles</title>
     <sect1 id="creation-dialog">
     <title>The puzzle creation dialog</title>
     <para>As described in <link linkend="toolbar-collection">the previous section</link>, you can create new puzzles by clicking on the <inlinemediaobject><imageobject><imagedata fileref="tools-wizard.png" format="PNG"/></imageobject></inlinemediaobject> <guiicon>Create New Puzzle...</guiicon> action icon in the puzzle collection window.</para>
     <para>Clicking this action icon opens the puzzle creation dialog, which consists of three pages:</para>
     <procedure>
       <step><para>On the first page, select an image file which will be sliced into pieces. Be sure to enter the correct metadata for the image: You should give attribution to the author of the image (&eg; the photographer or the painter); please respect the copyright of the image author.</para></step>
       <step><para>On the second page, you can select the type of pieces into which the image will be sliced. &palapeli; comes with a collection of slicers preinstalled, but third-party slicers may also be available.</para></step>
       <step><para>On the final page of the dialog, the selected slicer can be customized &eg; by choosing a different piece count or by adjusting parameters of the piece shape. The available set of options depends which slicer has been selected.</para></step>
     </procedure>
     <para>This manual will continue to discuss the slicers which come with &palapeli;. If you have downloaded a third-party slicer plugin for &palapeli;, please refer to the documentation of this plugin if you have trouble installing or using it on your system.</para>
     </sect1>
     <sect1 id="simple-slicers">
       <title>Simple slicers</title>
       <para>&palapeli; has two simple slicers, <guilabel>Classic jigsaw pieces</guilabel> and <guilabel>Rectangular pieces</guilabel>. These slicers create simple rectangular pieces either with or without connecting plugs.</para>
       <para>Both slicers allow the piece count and the aspect ratio to be adjusted. Dragging the <guilabel>Piece aspect ratio:</guilabel> slider to the left results in tall pieces, adjusting it to the right produces wide pieces. The default selection produces approximately square pieces.</para>
     </sect1>
     <sect1 id="psc">
       <title>The advanced &i18n-psc;</title>
       <para>The &i18n-psc; produces realistic jigsaw pieces with various basic patterns:</para>
       <variablelist>
         <varlistentry>
             <term><guilabel>Rectangular grid</guilabel></term>
           <listitem><para>Contains the well-known rectangular pieces.</para></listitem>
         </varlistentry>
         <varlistentry>
           <term><guilabel>Cairo grid</guilabel></term>
           <listitem><para>With its pentagonal pieces and unequal edge angles, it's rather hard to puzzle because the pieces fit together in an unfamiliar manner.</para></listitem>
         </varlistentry>
         <varlistentry>
           <term><guilabel>Hexagonal grid</guilabel></term>
           <listitem><para>Produces hexagonal pieces, arranged like honeycomb cells.</para></listitem>
         </varlistentry>
         <varlistentry>
           <term><guilabel>Rotrex grid</guilabel></term>
           <listitem><para>Through a special composition of triangular, hexagonal and rectangular pieces, the pieces form a pattern resembling to many intersecting circles.</para></listitem>
         </varlistentry>
         <varlistentry>
           <term><guilabel>Irregular grid</guilabel></term>
           <listitem><para>This grid is available only if you have installed <application>qvoronoi</application> from the <ulink url="https://www.qhull.org"><application>qhull</application> package</ulink>. <application>qvoronoi</application> is used to calculate irregular piece shapes from randomly placed points.</para></listitem>
         </varlistentry>
       </variablelist>
       <para>The &i18n-psc; has various parameters which control the appearance of the piece edges, especially the plugs on them. Default settings are provided for all of these parameters. An additional preset mode is available which reduces the amount of parameters to a bare minimum. The following parameters are available usually:</para>
       <variablelist>
         <varlistentry>
           <term><guilabel>Piece count:</guilabel></term>
           <listitem><para>Here set the exact number in which the image will sliced into pieces. This option only appear if the mathematical logic of the slicer selected allows any number.</para></listitem>
         </varlistentry>
         <varlistentry>
           <term><guilabel>Approx. piece count:</guilabel></term>
           <listitem><para>Here set the desired number in which the image will sliced into pieces. This option only appears if the mathematical logic of the selected slicer can readjust this number.</para></listitem>
         </varlistentry>
         <varlistentry>
           <term><guilabel>Flipped edge percentage:</guilabel></term>
           <listitem><para>The probability for each plug to be flipped. A plug is considered flipped if it points in the opposite direction as it would in a fully regular grid. On the rectangular grid, this results in pieces with 3 or 4 plugs pointing inwards resp. outwards. Position the slider at the very left to obtain the normal fully regular grid. In the middle, plug orientation is random. At the right, the grid is fully regular again, but with an <quote>alternate</quote> rule. This does <emphasis>not</emphasis> mean reversal of all plugs: In the alternate regular grid, for instance, each piece has four inward-pointing or four outward-pointing plugs. This setting has no effect in the irregular grid.</para></listitem>
         </varlistentry>
         <varlistentry>
           <term><guilabel>Edge curviness:</guilabel></term>
           <listitem><para>Determines how curvy the edges are, &ie; how strongly the borders dent in or bulge out. Move the slider to the very left to obtain straight edge lines (except for the plugs).</para></listitem>
         </varlistentry>
         <varlistentry>
           <term><guilabel>Plug size:</guilabel></term>
           <listitem><para>Determines the size of the plug part of each edge. The default setting (middle position of the slider) is chosen to look like a real puzzle. The slider ranges from 50% to 150% this size, which already looks obscenely large. The program tries very hard to avoid collisions between plugs. Colliding edges are reshaped multiple times and shrinked in small steps. However there still remain cases where no solution can be found, especially for large plug sizes.</para></listitem>
         </varlistentry>
         <varlistentry>
           <term><guilabel>Diversity of curviness:</guilabel></term>
           <listitem><para>Determines how much the curviness (see above) varies between edges. Move the slider to the left to make the dents and bulges look all the same. Position the slider at the right, there may occur very curvy and very straight borders.</para></listitem>
         </varlistentry>
         <varlistentry>
           <term><guilabel>Diversity of plug position:</guilabel></term>
           <listitem><para>Determines how much the position of the plug on the edge varies. Position the slider at the very left, plugs are affixed to the middle of their edge.</para></listitem>
         </varlistentry>
         <varlistentry>
           <term><guilabel>Diversity of plugs:</guilabel></term>
           <listitem><para>Determines how individual the plugs look like. Position the slider at the very left, plugs look all the same. At the very right, each plug will be a unique piece of art crafted especially for you.</para></listitem>
         </varlistentry>
         <varlistentry>
           <term><guilabel>Diversity of piece size:</guilabel></term>
           <listitem><para>Only for irregular grid: Determines how the piece size varies. A very small setting means nearly no variation; crystallite-like structure arise. Higher settings produce very small and very large pieces.</para></listitem>
         </varlistentry>
         <varlistentry>
           <term><guilabel>Dump grid image:</guilabel></term>
           <listitem><para>Save an image of the grid (black edges on white background) at <filename>~/goldberg-slicer-dump.png</filename>. If a previous dump exists, it is overwritten.</para></listitem>
         </varlistentry>
       </variablelist>
     </sect1>
   </chapter>
 
   <chapter id="puzzletable">
     <title>Playing on the puzzle table</title>
 
     <sect1 id="puzzletable-moves">
     <title>Basic moves</title>
     <screenshot><mediaobject>
       <imageobject><imagedata fileref="puzzletable1.png" format="PNG"/></imageobject>
       <textobject><phrase>The puzzle table (detail)</phrase></textobject>
     </mediaobject></screenshot>
     <para>The goal of the game is to assemble the given pieces into an image.</para>
     <para>The floating Preview window shows you what that image should be. Use a toolbar or menu item to show or hide the window. For a detailed description, see <link linkend="puzzletable-preview">The Preview window</link>.</para>
     <para>If you wish to attempt a puzzle that has 300 or more pieces, please read the chapter on <link linkend="large-puzzles">Facilities for solving large puzzles</link>, after you have read this chapter.</para>
     <para>You can move a single piece by clicking and dragging it with the &LMB;. That will leave the piece selected and highlighted. To move several pieces at once, first select and highlight them, then click and drag just one of the pieces. The rest will follow.</para>
     <para>You can select and highlight multiple pieces by holding &Ctrl; and clicking on them, or by dragging a rubberband around them with the &LMB;. You can also hold the &Ctrl; key and click with the &LMB; to increase or decrease the current selection one piece at a time.</para>
     <para>To remove selection and highlighting, just click on an empty spot on the puzzle table or on a piece that is not already selected.</para>
     <para>When you put one piece near a neighboring piece, both pieces will automatically snap together and become joined (1). After pieces have been snapped together, they cannot be torn apart. Another difference between &palapeli; and a real-world jigsaw puzzle is that you cannot combine two pieces that are not true neighbors.</para>
     <para>The progress bar below the puzzle table indicates your progress by counting joined pieces (2). &palapeli; will automatically save your progress after every move, so you do not have to worry about saving.</para>
     <para>You can zoom the puzzle table view in or out with the mouse <mousebutton>wheel</mousebutton>, and at the bottom right (3) with the buttons and the slider.</para>
     <para>You can move the puzzle table view in any direction by clicking and dragging with the &RMB;.</para>
     <para>The movement of the pieces is limited by the <emphasis>puzzle table area</emphasis>. This area is represented on the puzzle table's background by a light rectangular shade. When you move pieces to the border (4) of the puzzle table area, the area will automatically expand to give you more space for moving your puzzle pieces. Near the shaded borders, the mouse cursor changes into a double-headed arrow, indicating that you can adjust the puzzle table area by clicking there and dragging with the &LMB;.</para>
     <para>You can lock the puzzle table area with the small button (5) to the right of the progress bar. The shade (4) around the puzzle table will darken, and pieces will now stop moving at the edges of the puzzle table area. It is still possible to adjust the size of the puzzle table area manually.</para>
     </sect1>
 
     <sect1 id="puzzletable-preview">
       <title>The Preview window</title>
       <para>The Preview is a small window that floats
       above or to one side of the puzzle table window. It
       contains an image of the completed puzzle: the picture
       that would appear on top of the box if this was a
       real-world jigsaw puzzle.
       </para>
       <para>The window can be shown or hidden by using the
       <inlinemediaobject><imageobject><imagedata fileref="view-preview.png" format="PNG"/>
       </imageobject></inlinemediaobject> <guiicon>Preview</guiicon>
       action icon in the toolbar or the <menuchoice><guimenu>View</guimenu>
       <guimenuitem>Preview</guimenuitem></menuchoice> menu item. Its
       size, position and visible or not visible setting
       are saved and restored between runs of &palapeli;.
       </para>
       <para>Being a window, it can be freely moved around
       the desktop and resized. Its <guibutton>Close</guibutton>
       button will hide it and its <guibutton>Maximize</guibutton>
       button will expand or contract the picture rapidly.
       </para>
       <para>The Preview window has a magnification
       feature, so it need not take up much space.
       If you move the mouse over the window,
       it zooms in quickly to reveal a magnified view
       of the area under the mouse and the equivalent
       of a few pieces around it. This is very useful
       for viewing details of the puzzle and identifying
       pieces you have found, but it can be tricky to
       control, especially near the edges of the picture.
       </para>
     </sect1>
 
     <sect1 id="puzzletable-mouseactions">
       <title>Mouse interactions</title>
       <para>As described in the previous section, there are plenty of ways to interact with &palapeli;'s puzzle table using the mouse. You can configure freely which actions are triggered by which mouse buttons. (See <link linkend="configuration-mouseactions">Game Configuration</link> section for more information on how to configure this.) The following list summarizes all possible mouse actions:</para>
       <variablelist>
         <varlistentry>
           <term><action>Change size of puzzle table area by dragging its edges</action></term>
           <listitem><para>By default, this action is assigned to the &LMB;.</para></listitem>
         </varlistentry>
         <varlistentry>
           <term><action>Move pieces by dragging</action></term>
           <listitem><para>When you click and drag a puzzle piece, this piece will be moved. If multiple pieces have been selected and you click and drag one of these pieces, then all pieces are moved. By default, this action is assigned to the &LMB;.</para></listitem>
         </varlistentry>
         <varlistentry>
           <term><action>Move viewport by dragging</action></term>
           <listitem><para>This action moves the view of the entire puzzle table in any direction. By default, it is assigned to the &RMB;.</para></listitem>
         </varlistentry>
         <varlistentry>
           <term><action>Select several pieces by rubber banding</action></term>
           <listitem><para>When you click on a free area of the puzzle table instead of a puzzle piece, you can drag a rubberband. When you let the mouse button go, all pieces inside the rubberband are selected. All other pieces are deselected. By default, this action is assigned to the &LMB;.</para></listitem>
         </varlistentry>
         <varlistentry>
           <term><action>Select multiple pieces at once</action></term>
           <listitem><para>When you click on a puzzle piece, it will be selected or, if it was already selected, it will be deselected. It can also be used to adjust a rubberband selection. By default, this action is assigned to the &LMB; and only available when &Ctrl; is pressed.</para></listitem>
         </varlistentry>
         <varlistentry>
           <term><action>Clear selections and highlighting</action></term>
           <listitem><para>Click on an empty spot in the puzzle table or on a piece that is not already selected.</para></listitem>
         </varlistentry>
         <varlistentry>
           <term><action>Zoom the puzzle table view in or out</action></term>
           <listitem><para>This action is identical to clicking the buttons either side of the slider (3) on the status bar. It is assigned to the mouse <mousebutton>wheel</mousebutton> by default.</para></listitem>
         </varlistentry>
         <varlistentry>
           <term><action>Switch to close-up or distant view</action></term>
           <listitem><para>This action alternates (toggles) between a close-up and distant view, at the position of the mouse pointer. It is intended mainly to provide fast zooming in large puzzles (300 pieces or more).  For more detail, see <link linkend="large-puzzle-fast-zooming">Fast zooming between close-up and distant view</link>. By default, the action is assigned to the &MMB;.</para></listitem>
         </varlistentry>
         <varlistentry>
           <term><action>Teleport pieces to or from a holder</action></term>
           <listitem><para>This action helps you collect, sort and move pieces rapidly in large puzzles (300 pieces or more) without dragging and dropping. You can use it in smaller puzzles if you wish. For more detail, see <link linkend="large-puzzle-holders">Using piece-holders</link>. By default, the action is assigned to the &LMB; and only available when &Shift; key is pressed.</para></listitem>
         </varlistentry>
         <varlistentry>
           <term><action>Toggle lock state of the puzzle table area</action></term>
           <listitem><para>This action is identical to pressing the button (5) on the status bar. By default, this action is not assigned to any mouse button, but you can enable it from <link linkend="configuration-mouseactions">the configuration dialog</link>.</para></listitem>
         </varlistentry>
         <varlistentry>
           <term><action>Scroll viewport horizontally</action> and <action>Scroll viewport vertically</action></term>
           <listitem><para>By default, this action is not assigned to the mouse <mousebutton>wheel</mousebutton>, but you can enable it from <link linkend="configuration-mouseactions">the configuration dialog</link>.</para></listitem>
         </varlistentry>
       </variablelist>
     </sect1>
 
     <sect1 id="toolbars-puzzletable">
       <title>Toolbar overview</title>
       <variablelist>
         <varlistentry>
           <term><inlinemediaobject><imageobject><imagedata fileref="go-previous.png" format="PNG"/></imageobject></inlinemediaobject> <guiicon>Back to Collection</guiicon></term>
           <listitem><para><action>Go back to the collection to choose another puzzle.</action> Can be used only when you are solving a puzzle.</para></listitem>
         </varlistentry>
         <varlistentry>
           <term><inlinemediaobject><imageobject><imagedata fileref="view-preview.png" format="PNG"/></imageobject></inlinemediaobject> <guiicon>Preview</guiicon></term>
           <listitem><para><action>Toggle the display of the preview window with the completed puzzle.</action></para></listitem>
         </varlistentry>
       </variablelist>
     </sect1>
   </chapter>
 
   <chapter id="large-puzzles">
     <title>Facilities for solving large puzzles</title>
 
     <sect1 id="large-puzzle-general">
       <title>General principles</title>
       <para>&palapeli; can handle large puzzles from 300 to
       10,000 pieces, but you need some special facilities to
       help you work with them on a small screen.
       </para>
       <para>You can create a large puzzle in exactly the
       same way as a smaller puzzle. See the chapter on
       <link linkend="create-puzzles">Creating new
       puzzles</link>, but there are some things you
       need to think about before you begin. For details see
       <link linkend="large-puzzle-creation">Creating large
       puzzles - special concerns</link>.
       </para>
       <para>The Preview window is very useful in large
       puzzles: see the section about it for a
       <link linkend="puzzletable-preview">detailed description</link>.
       </para>
       <para>Managing space and moving around are your next
       concerns. When you zoom out to view the whole puzzle
       table, it becomes hard to see individual pieces. If
       you zoom in and find a piece you are looking for, it
       is unlikely that the place where it goes will be
       visible in the view.
       See the <link linkend="large-puzzle-space">Managing
       space and moving around</link> section for some
       solutions to these problems and others.
       </para>
       <para>Finally, you need to collect pieces and convey
       them to your solution area in some more efficient
       way than repetitive dragging and dropping over
       large distances. This is where piece-holders come in.
       </para>
       <para>When you start a large puzzle, you are given
       a holder (a small floating window) called <quote>Hand</quote>
       into which you can put pieces when and wherever
       you see them. Then you can drop them near your
       solution and work out where each piece has to go.
       This is like collecting pieces in one hand as you
       scan a large real-world jigsaw puzzle.
       </para>
       <para>You may need some systematic way to collect
       and sort pieces by common attributes (&eg; edges, sky,
       skyline, &etc;) and so you can use as many holders
       as you like and give them names. Holders are saved
       continually, along with the puzzle table, which
       means you can use them to build up parts of the
       solution and store them or even to store pieces
       that you wish to put into a <quote>too hard basket</quote>
       until later. For details on how to use holders
       see the <link linkend="large-puzzle-holders">Using
       piece-holders</link> section.
       </para>
       <para>Finally, the <link linkend="puzzletable-mouseactions">Mouse interactions</link>
       section lists the two special mouse actions that
       make working with large puzzles quicker and easier:
       teleporting pieces and zooming to close-up or
       distant view.
       </para>
     </sect1>
 
     <sect1 id="large-puzzle-creation">
       <title>Creating large puzzles - special concerns</title>
       <para>Before you create a large puzzle, you should make
       sure that the image in your source contains enough
       detail (&ie; enough megapixels). You can use a file
       utility or photo viewer/editor to find out how many
       pixels wide and high your picture is when not compressed
       by JPEG or other image format. As a rough rule of thumb,
       allow one megapixel per 1,000 pieces. That will give
       each piece about 1,000 pixels or more than 30 by 30
       pixels, making the pieces
       reasonably sharp at the edges and clear to see when you
       zoom in. You can work with fewer megapixels, but it may
       be hard to distinguish and recognize pieces during play.
       </para>
       <para>When you create or restart a large puzzle, it may
       be best to avoid using the bevel and shadowing features
       of &palapeli; (see the
       <link linkend="configuration-general">General
       settings</link> section), because they make loading
       slower and highlighting harder to see when the pieces
       in the view are very small. More prominent highlighting
       appears when shadowing is not used.
       </para>
     </sect1>
 
     <sect1 id="large-puzzle-space">
       <title>Managing space and moving around</title>
       <sect2 id="large-puzzle-space-allocation">
       <title>Allocating space on the puzzle table</title>
       <para>When you create or restart a puzzle, the
       pieces are shuffled and placed randomly into grid
       locations on the puzzle table. Two settings affect
       the space required, see
       <link linkend="configuration">Game Configuration</link>
       for a list of settings provided via
       <menuchoice><guimenu>Settings</guimenu>
       <guimenuitem>Configure &palapeli;...</guimenuitem>
       </menuchoice> or, on &macOS;,
       <menuchoice><guimenu>&palapeli;</guimenu>
       <guimenuitem>Preferences...</guimenuitem></menuchoice>
       menu item.
       </para>
       <para>The spacing of pieces in puzzle grids can be
       set from 1.0 to 1.5 times the height and width of
       the highest and widest pieces. Smaller settings
       pack the pieces into the view better, but larger
       ones allow more space for dragging, dropping and
       rubber banding. The default is 1.3, but 1.1 is
       very workable in large puzzles. The setting
       applies to puzzles of all sizes, and also
       affects grids used with piece-holders (see
       <link linkend="large-puzzle-holders">Using
       piece-holders</link>) or when re-arranging
       pieces automatically on the puzzle table, using the
       <menuchoice><shortcut><keycap>R</keycap></shortcut>
       <guimenu>Move</guimenu><guimenuitem>Rearrange
       Pieces</guimenuitem></menuchoice> menu item.
       </para>
       <para>The other setting provides space on the
       puzzle table of exactly the right size for
       building your solution. The default is for it
       to appear in the center, with the pieces
       distributed evenly around the outside. On
       average, this should put the pieces closest to
       where they have to go eventually. You can also
       choose to use any of the four corners or have
       no space (option <guilabel>None</guilabel>), in
       which case you have to clear space manually,
       perhaps by expanding the puzzle table area (see
       <link linkend="puzzletable-moves">Basic moves</link>).
       The solution space setting affects puzzles
       down to 20 pieces, but with fewer than 20 pieces
       solution spaces are pointless.
       </para>
       <para>As the puzzle solution progresses, pieces
       move into the solution area and leave spaces
       elsewhere. It may be helpful to pack the
       remaining pieces closer together. If so, select
       some pieces using rubber banding or hold the &Ctrl;
       key and click with the &LMB;, then use the
       <menuchoice><shortcut><keycap>R</keycap></shortcut>
       <guimenu>Move</guimenu>
       <guimenuitem>Rearrange Pieces</guimenuitem></menuchoice>
       menu item or simply the shortcut (default is the
       <keycap>R</keycap> key). The pieces are packed into
       a grid and remain selected, so that they can be
       easily moved to a better position, if required.
       This is also a way to gather together pieces
       with some common attribute, but using
       piece-holders is more powerful.
       </para>
       </sect2>
       <sect2 id="large-puzzle-fast-zooming">
       <title>Fast zooming between close-up and distant view</title>
       <para>When a puzzle is loaded, &palapeli;
       calculates distant and close-up views and
       displays the distant view, which shows the
       entire puzzle table area. The close-up view
       shows pieces at a convenient viewing size for
       your eyes and your screen and desktop. Use
       the &MMB; to switch quickly between the two
       views, at a location where the mouse is
       pointing. Then you can home in quickly on any
       piece in the puzzle table and see what shape
       it is and what part of the picture it contains.
       </para>
       <para>You can adjust the scale of either view by
       zooming manually and your setting will be
       remembered next time you switch the view by
       using the &MMB;. Puzzles of all sizes have the
       fast zooming feature, but in puzzles with less
       than 100 pieces the two views are almost the
       same as each other. In other words, the pieces
       are easy to see when you view the whole puzzle table.
       </para>
       </sect2>
       <sect2 id="large-puzzle-navigating">
       <title>Moving around in a large puzzle</title>
       <para>The hard way to move pieces in a large puzzle
       is to select them and then alternately drag the
       pieces and the puzzle table (&LMB; and &RMB;)
       until you get to your destination. A much easier
       way to do the same thing is to select the pieces,
       zoom to distant view (&MMB;, see above), drag
       the pieces to the destination in one move (&LMB;)
       and then zoom to close-up view (&MMB;). This is
       also a good way to retrieve a single stray piece,
       but dragging that tiny piece across the puzzle
       table, without losing the selection, can be
       tricky if there are thousands of pieces.
       </para>
       <para>Another way to navigate and search the puzzle
       table systematically is to zoom in on the top
       left corner (&MMB;), then use the empty spaces
       in the scroll bars to step through the table
       horizontally or vertically, one fixed-size
       <quote>page</quote> at a time. This technique is very
       effective when you are using piece-holders to
       collect pieces you are looking for. If you
       keep the close-up scale fixed and always start
       at the same place, you will always get <quote>pages</quote>
       of fixed size and contents.
       </para>
       </sect2>
       <sect2 id="large-puzzle-visibility">
       <title>Visibility of pieces in large puzzles</title>
       <para>In large jigsaw puzzles on a small screen it
       can be hard to see what you are doing. For
       example, with a 10,000 piece puzzle on a
       1440 by 900 screen, the pieces in the distant
       view of the puzzle table are about 7 pixels
       across. At this scale, it is hard to see picture,
       color, piece-shape or even highlighting.
       </para>
       <para>&palapeli; has always had a choice of
       backgrounds and background colors and that
       helps visibility. Added to these is a more
       prominent highlighting scheme, which appears
       if you do not choose shadowing, and a setting
       to choose the color of the highlight, to
       contrast with the background and most pieces.
       Also these settings are now saved and restored
       with each puzzle. So each puzzle can have the
       background and highlighting that best suits
       its overall picture. It is worth experimenting
       with settings when you create a large puzzle,
       but you may need to reload or restart the
       puzzle before all changes can take effect.
       </para>
       </sect2>
     </sect1>
 
     <sect1 id="large-puzzle-holders">
       <title>Using piece-holders</title>
       <sect2 id="large-puzzle-whatareholders">
       <title>What are piece-holders?</title>
       <para>Piece-holders are perhaps the most useful
       feature of &palapeli; for helping solve large
       puzzles. They are small, floating windows into
       which you can sort groups of pieces, such as
       <quote>edges</quote>, <quote>sky</quote>,
       <quote>skyline</quote> or <quote>white house on
       left</quote>. Initially they appear at a minimum size
       which is just large enough to show four pieces at
       close-up scale, so they are quite easy to fit
       in next to the main puzzle table window.
       </para>
       <para>Being windows, holders can be freely moved
       around the desktop and resized. The <guibutton>Close</guibutton>
       button will delete the holder, but only if it contains
       no pieces. The <guibutton>Maximize</guibutton> button
       will expand or contract the holder rapidly. The holder
       can contain any number of pieces (maybe hundreds). A
       maximize action can be useful when reviewing the contents
       or constructing a sub-assembly inside the holder.
       </para>
       <para>You can have as many holders as you like.
       There is usually one which is active - outlined
       in blue. It is the target for actions such as
       transferring pieces or deleting a holder.
       </para>
       </sect2>
       <sect2 id="large-puzzle-createholders">
       <title>Creating and deleting holders</title>
       <para>When you start a large puzzle, a holder
       called <quote>Hand</quote> is created automatically.
       This may be the only holder you need with puzzles
       of 300 to 750 pieces, but you can have as many
       holders as you like, even with puzzles of less
       than 300 pieces.
       </para>
       <para>To create or delete a holder, use the
       <menuchoice><shortcut><keycap>C</keycap></shortcut>
       <guimenu>Move</guimenu><guimenuitem>
       Create Piece Holder...</guimenuitem></menuchoice>
       or <menuchoice><shortcut><keycap>D</keycap></shortcut>
       <guimenu>Move</guimenu><guimenuitem>
       Delete Piece Holder</guimenuitem></menuchoice> menu items, or
       simply the <keycap>C</keycap> and <keycap>D</keycap>
       keys, or the <guibutton>Close</guibutton> button to
       delete. When you create a holder, you are asked to
       give it a name, but that is not essential. Usually
       the holder is at close-up scale and you can easily
       see what kind of piece is in it.
       </para>
       <para>When you delete a holder, it must be active
       (outlined in blue) and empty of pieces. If the
       holder to be deleted is not active, click on it.
       After deletion, there is no active holder, so
       click on one of those that are left.
       </para>
       </sect2>
       <sect2 id="large-puzzle-teleporting">
       <title>Transferring pieces into and out of holders</title>
       <para>Transferring pieces by dragging and dropping
       is not possible with holders, nor is it needed.
       Instead, you can transfer pieces instantly by
       <quote>teleporting</quote>, as in <quote>Star Trek</quote>.
       Teleporting works by hold the &Shift; key and click with the &LMB;.
       </para>
       <para>To transfer pieces to a holder, make sure your
       target holder is active (outlined in blue),
       then select some pieces on the puzzle table
       and hold the &Shift; key and click with the &LMB;. Or you can
       just click on one piece at a time by hold the &Shift;
       key and click with the &LMB;. The transferred pieces vanish from
       the puzzle table and reappear, highlighted,
       in the holder. As they arrive, they are
       automatically packed into a grid and the last
       piece transferred is centered in the view.
       </para>
       <para>To transfer pieces out of a holder, select
       a piece or pieces inside the holder, then
       return to the puzzle table and click on an
       empty spot where you would like the piece(s)
       to appear, hold the &Shift; key and click with the &LMB;. Avoid
       clicking on a piece that is already on the
       puzzle table: it will send the piece to the
       holder - not what you want. If you accidentally
       do this with a large joined-up piece
       (&ie; part of your solution), there
       is a warning message and an opportunity to cancel.
       </para>
       <para>Pieces stay highlighted after teleporting.
       That allows you to reverse the action quickly
       if you accidentally transfer the wrong pieces
       or use the wrong holder. Also, on the puzzle
       table, you can easily adjust the position of
       a piece or pieces that have just arrived or move
       a piece into the solution.
       </para>
       <para>Teleporting also works between holders.
       Start as if you are going to transfer pieces
       to the puzzle table, but then by hold the &Shift;
       key and click with the &LMB; in an empty spot in
       another holder. To reverse the process, go back
       to the original holder and hold the &Shift; key
       and click with the &LMB; again.
       </para>
       </sect2>
       <sect2 id="large-puzzle-sorting">
       <title>Sorting pieces</title>
       <para>To sort pieces into holders efficiently
       as you search through a large puzzle, use the
       technique for stepping through the puzzle a
       <quote>page</quote> at a time,
       <link linkend="large-puzzle-navigating">
       as described earlier</link>, combined with
       holders and teleporting to collect pieces
       as you go. When you have scanned the whole puzzle
       table, zoom to a close-up of your solution area and
       place the pieces you have collected. Or you
       can pre-assemble pieces in holders.
       </para>
       </sect2>
       <sect2 id="large-puzzle-otherholderactions">
       <title>Other holder actions</title>
       <para>Piece-holders support all the functions
       of the puzzle table (see <link linkend="puzzletable-moves">Basic moves</link>), except
       that you can only zoom by using the scroll-<mousebutton>wheel</mousebutton>
       or the &MMB;.
       </para>
       <para>This means that you can use a holder as an
       extra puzzle table, if you wish. You can drag
       and drop, join pieces together, move the
       boundaries of the area, &etc; You can also
       teleport assembled pieces of any size into
       or out of a holder, but beware of overlaps
       or small pieces being hidden.
       </para>
       <para>Finally, you can use the <menuchoice><shortcut>
       <keycap>A</keycap></shortcut><guimenu>Move</guimenu>
       <guimenuitem>Select all in holder</guimenuitem>
       </menuchoice> menu item, followed by <menuchoice><shortcut>
       <keycap>R</keycap></shortcut><guimenu>Move</guimenu>
       <guimenuitem>Rearrange Pieces</guimenuitem>
       </menuchoice> menu item or hold the &Shift; key and click with the
       &LMB;, to re-pack all the pieces in the holder or empty
       all the pieces out onto the puzzle table. Or just use the
       <keycap>A</keycap> or <keycap>R</keycap> keys on the
       currently selected holder.
       </para>
       </sect2>
     </sect1>
   </chapter>
 
   <chapter id="interface">
     <title>Interface Overview</title>
     <para>The following are &palapeli;'s menu items, some of which are also available as action icons in the toolbar and keyboard shortcuts.</para>
     <variablelist>
       <varlistentry>
         <term><menuchoice><shortcut><keycombo action="simul">&Ctrl;<keycap>N</keycap></keycombo> </shortcut> <guimenu>Game</guimenu> <guimenuitem>Create New Puzzle...</guimenuitem></menuchoice></term>
         <listitem><para><action>Opens a dialog which allows you to create a puzzle from an image on your disk.</action> See <link linkend="create-puzzles">the corresponding section</link> for details and also <link linkend="large-puzzle-creation">special concerns</link>, if you are going to create a puzzle with 300 or more pieces.</para></listitem>
       </varlistentry>
       <varlistentry>
         <term><menuchoice><guimenu>Game</guimenu><guimenuitem>Import from File...</guimenuitem></menuchoice></term>
         <listitem><para><action>When you have received a &palapeli; puzzle file (which can usually be recognized by the file extension <literal role="extension">.puzzle</literal>), you can use this action to import it into your local collection.</action> Puzzle files can also be played by simply clicking on them in the file manager of your choice, but after the import, the puzzle will appear in your local collection, and you can safely delete the downloaded puzzle file.</para></listitem>
       </varlistentry>
       <varlistentry>
         <term><menuchoice><guimenu>Game</guimenu><guimenuitem>Export to File...</guimenuitem></menuchoice></term>
         <listitem><para><action>This will export the currently selected puzzles to files, in order to enable you to give them to your friends, publish them on the web, or make backup copies of your collection.</action></para></listitem>
       </varlistentry>
       <varlistentry>
         <term><menuchoice><guimenu>Game</guimenu><guimenuitem>Delete Puzzle</guimenuitem></menuchoice></term>
         <listitem><para><action>Any puzzles that you have selected in the puzzle list, will be permanently deleted from your collection.</action></para><warning><para>This action cannot be undone.</para></warning></listitem>
       </varlistentry>
       <varlistentry>
         <term><menuchoice><guimenu>Game</guimenu><guimenuitem>Restart Puzzle...</guimenuitem></menuchoice></term>
         <listitem><para><action>Re-shuffle all the pieces and discard the saved progress for the current puzzle.</action></para></listitem>
       </varlistentry>
       <varlistentry>
         <term><menuchoice><shortcut><keycombo action="simul">&Ctrl;<keycap>Q</keycap></keycombo> </shortcut> <guimenu>Game</guimenu> <guimenuitem>Quit</guimenuitem></menuchoice></term>
         <listitem><para><action>Quit</action> the &palapeli;.</para></listitem>
       </varlistentry>    
       <varlistentry>
         <term><menuchoice><shortcut><keycap>C</keycap></shortcut><guimenu>Move</guimenu><guimenuitem>Create Piece Holder...</guimenuitem></menuchoice></term>
         <listitem><para><action>Create a temporary holder for storing or sorting pieces. See <link linkend="large-puzzle-holders">Using piece-holders</link> for details of how to use a holder.</action></para></listitem>
       </varlistentry>
       <varlistentry>
         <term><menuchoice><shortcut><keycap>D</keycap></shortcut><guimenu>Move</guimenu><guimenuitem>Delete Piece Holder</guimenuitem></menuchoice></term>
         <listitem><para><action>Delete a selected temporary holder when it is empty.</action></para></listitem>
       </varlistentry>
       <varlistentry>
         <term><menuchoice><shortcut><keycap>A</keycap></shortcut><guimenu>Move</guimenu><guimenuitem>Select All in Holder</guimenuitem></menuchoice></term>
         <listitem><para><action>Select all pieces in the currently selected piece-holder (outlined in blue).</action></para></listitem>
       </varlistentry>
       <varlistentry>
         <term><menuchoice><shortcut><keycap>R</keycap></shortcut><guimenu>Move</guimenu><guimenuitem>Rearrange Pieces</guimenuitem></menuchoice></term>
         <listitem><para><action>Rearrange selected pieces in any holder or the puzzle table by packing them into a grid.</action></para></listitem>
       </varlistentry>
       <varlistentry>
         <term><menuchoice><guimenu>View</guimenu><guimenuitem>Back to Collection</guimenuitem></menuchoice></term>
         <listitem><para><action>Go back to the collection to choose another puzzle.</action> Can be used only when you are solving a puzzle.</para></listitem>
       </varlistentry>
 
       <varlistentry>
         <term><menuchoice><guimenu>View</guimenu><guimenuitem>Preview</guimenuitem></menuchoice></term>
         <listitem><para><action>Toggle the display of the completed puzzle preview image.</action> Hover it with the mouse pointer to zoom in the image.</para></listitem>
       </varlistentry>
       <varlistentry>
         <term><menuchoice><shortcut><keycombo action="simul">&Ctrl;<keycap>+</keycap></keycombo></shortcut><guimenu>View</guimenu><guimenuitem>Zoom In</guimenuitem></menuchoice></term>
         <listitem><para><action>Increase the scale.</action></para></listitem>
       </varlistentry>
       <varlistentry>
         <term><menuchoice><shortcut><keycombo action="simul">&Ctrl;<keycap>-</keycap></keycombo></shortcut><guimenu>View</guimenu><guimenuitem>Zoom Out</guimenuitem></menuchoice></term>
         <listitem><para><action>Decrease the scale.</action></para></listitem>
       </varlistentry>
       <varlistentry>
         <term><menuchoice><guimenu>Settings</guimenu><guimenuitem>Enable All Messages</guimenuitem></menuchoice></term>
         <listitem><para><action>Allows you to enable all messages disabled by checking the <guilabel>Do not show this message again</guilabel> option in the &palapeli; confirmation dialogs.</action></para></listitem>
       </varlistentry>
       <varlistentry>
         <term><menuchoice><guimenu>Settings</guimenu><guimenuitem>Show Statusbar of Puzzle Table</guimenuitem></menuchoice></term>
         <listitem><para><action>Toggle the display of the progress bar and buttons below the puzzle table.</action> This action will change nothing in the puzzle collection.</para></listitem>
       </varlistentry>
       <varlistentry id="settings-menu-configure">
         <term><menuchoice><guimenu>Settings</guimenu><guimenuitem>Configure &palapeli;...</guimenuitem></menuchoice></term>
         <listitem><para>Open a game configuration dialog. See <link linkend="configuration">Game Configuration</link> section for more details.</para>
         </listitem>
       </varlistentry>
     </variablelist>
     <para>
       Additionally &palapeli; has the common &kde; <guimenu>Settings</guimenu> and <guimenu>Help</guimenu>
       menu items, for more information read the sections about the <ulink url="help:/fundamentals/menus.html#menus-settings">Settings Menu</ulink> and <ulink url="help:/fundamentals/menus.html#menus-help">Help Menu</ulink> of the &kde; Fundamentals.
     </para>
   </chapter>
 
   <chapter id="configuration">
     <title>Game Configuration</title>
     <para>To open the configuration dialog, use the menu item: <menuchoice><guimenu>Settings</guimenu><guimenuitem>Configure &palapeli;...</guimenuitem></menuchoice></para>
     <sect1 id="configuration-general">
       <title>General settings</title>
       <variablelist>
         <varlistentry>
           <term><guilabel>Puzzle table</guilabel></term>
           <listitem>
             <para>Lets you choose some parameters of the puzzle table.</para>
           <variablelist>
             <varlistentry>
               <term><guilabel>Background:</guilabel></term>
               <listitem><para><action>Lets you choose another background texture for the puzzle table.</action> If you choose a single color instead of a texture, the button besides the selection box can be used to define the color.</para></listitem>
             </varlistentry>
             <varlistentry>
               <term><guilabel>Color for highlighting selected pieces:</guilabel></term>
               <listitem><para><action>Lets you choose the highlighting color of pieces when they are selected.</action> Click on the button to the right of the label to open the <ulink url="help:/fundamentals/colors.html">Color Selector</ulink> window.</para></listitem>
             </varlistentry>
             <varlistentry>
               <term><guilabel>Space for solution:</guilabel></term>
               <listitem><para><action>Lets you choose where to reserve some space on the puzzle table for building the solution.</action> No space is provided if you select option <guilabel>None</guilabel> or the puzzle has less than 20 pieces. Changes will take effect when a puzzle is created or re-started.</para></listitem>
             </varlistentry>
             <varlistentry>
               <term><guilabel>Spacing of pieces in puzzle grids (1.0-1.5):</guilabel></term>
               <listitem><para><action>Lets you choose the spacing in puzzle grids.</action> Changes in the overall puzzle spacing will take effect only when a puzzle is created or re-started.</para></listitem>
             </varlistentry>
           </variablelist>
           </listitem>
         </varlistentry>
         <varlistentry>
           <term><guilabel>Piece appearance</guilabel></term>
           <listitem><para><action>Controls the appearance of pieces on the puzzle table.</action> If &palapeli; is running slowly or puzzles take a long time to open, you can disable the graphical effects in this category and speed up everything. If you choose shadowing, highlighting is implemented by changing the color of the shadow.</para></listitem>
         </varlistentry>
         <varlistentry>
           <term><guilabel>Snapping precision</guilabel></term>
           <listitem><para><action>Lets you choose how closely neighboring pieces must be positioned before they snap together.</action> If you move the slider to the right, pieces will snap together even if they are not so close. This makes the game a bit easier to play.</para></listitem>
         </varlistentry>
       </variablelist>
     </sect1>
     <sect1 id="configuration-mouseactions">
       <title>Mouse interaction</title>
       <para>This page of the configuration dialog allows you to change the assignments of mouse buttons and modifier keys to the actions described in <link linkend="puzzletable-mouseactions">Playing on the puzzle table, Mouse interactions</link>. Care should be taken to avoid ambiguous assignments. Three of the default assignments can go to the &LMB; because the pointer is over different areas when you use them, but the other assignments must be distinct.</para>
       <para>The interactions are divided into those that can be assigned to mouse buttons (&eg; <action>Move viewport by dragging</action>), and those that can be assigned to the mouse <mousebutton>wheel</mousebutton> (&eg; <action>Scroll viewport horizontally</action>).</para>
       <sect2>
         <title>Mouse Buttons tab</title>
         <para>To the right of the name of each interaction is a button with a picture of a computer mouse which shows the currently assigned action. You can configure the interaction by clicking on that button with the &LMB; and then with the mouse button which you wish to assign to this interaction. If you hold modifier keys while clicking for the second time, the puzzle table will allow this interaction only while these modifiers are being held.</para>
         <tip><para>Instead of clicking, you can also press &Space; to assign the special <guilabel>No-Button</guilabel> to this interaction. This is only allowed if modifier keys are being held. The <guilabel>No-Button</guilabel> means that the modifier keys take the role of the mouse button: The interaction starts when the modifier keys are pressed, and stops when one of the modifier keys is released.</para></tip>
       </sect2>
       <sect2>
         <title>Mouse Wheel tab</title>
         <para>This tab works similarly to the previous one. When the button on the right asks for input, you have to turn the mouse <mousebutton>wheel</mousebutton> instead of clicking a mouse button. Holding modifier keys is allowed, too, with the same consequences as in the previous case.</para>
         <tip><para>If your mouse has a bidirectional mouse <mousebutton>wheel</mousebutton> (as most commonly found on notebook touchpads), you can take advantage of this: The button will recognize whether you turned the mouse <mousebutton>wheel</mousebutton> horizontally or vertically.</para></tip>
       </sect2>
     </sect1>
   </chapter>
 
   <chapter id="credits">
     <title>Credits and License</title>
     <para>&palapeli; aims to bring the unagitated fun and challenge of jigsaw puzzles to your desktop.</para>
     <para>The idea was first developed by Bernhard Schiffner, together with Stefan Majewsky, who was the leading developer of &palapeli;.</para>
     <para>The &i18n-psc; was contributed by Johannes L&#xF6;hnert.</para>
     <para>The large-puzzle facilities were contributed by Ian Wadham.</para>
     <para>Documentation Copyright 2009, 2010 Johannes L&#xF6;hnert, Stefan Majewsky and Copyright 2014 Ian Wadham.</para>
     <!-- TRANS:CREDIT_FOR_TRANSLATORS -->
     &underFDL;
     &underGPL;
   </chapter>
 
   &documentation.index;
 </book>