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  4.   <head>
  5.     <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
  6.     <title>7.8.¬† Selection Editor</title>
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  13.     <link rel="up" href="gimp-imagewindow-menus-select.html" title="7.¬† The ‚ÄúSelect‚Äù Menu" />
  14.     <link rel="prev" href="gimp-selection-from-path.html" title="7.7.¬† From Path" />
  15.     <link rel="next" href="gimp-selection-feather.html" title="7.9.¬† Feather" />
  16.   </head>
  17.   <body>
  18.     <div class="navheader">
  19.       <table width="100%" summary="Navigation header">
  20.         <tr>
  21.           <th colspan="3" align="center">7.8.¬†
  22.     <span lang="en" xml:lang="en">Selection Editor</span>
  23.   </th>
  24.         </tr>
  25.         <tr>
  26.           <td width="20%" align="left"><a accesskey="p" href="gimp-selection-from-path.html"><img src="../images/prev.png" alt="Prev" /></a>¬†</td>
  27.           <th width="60%" align="center">7.¬†
  28.     <span lang="en" xml:lang="en">The ‚Äú<span class="quote">Select</span>‚Äù Menu</span>
  29.   </th>
  30.           <td width="20%" align="right">¬†<a accesskey="n" href="gimp-selection-feather.html"><img src="../images/next.png" alt="Next" /></a></td>
  31.         </tr>
  32.       </table>
  33.       <hr />
  34.     </div>
  35.     <div class="sect2" lang="en" xml:lang="en">
  36.       <div class="titlepage">
  37.         <div>
  38.           <div>
  39.             <h3 class="title"><a id="gimp-selection-dialog"></a>7.8.¬†
  40.     <span lang="en" xml:lang="en">Selection Editor</span>
  41.   </h3>
  42.           </div>
  43.           <div>
  44.             <div class="revhistory">
  45.               <table border="1" width="100%" summary="Revision history">
  46.                 <tr>
  47.                   <th align="left" valign="top" colspan="3">
  48.                     <b>Revision History</b>
  49.                   </th>
  50.                 </tr>
  51.                 <tr>
  52.                   <td align="left">Revision $Revision: 2435 $</td>
  53.                   <td align="left">2006-08-14</td>
  54.                   <td align="left">scb</td>
  55.                 </tr>
  56.               </table>
  57.             </div>
  58.           </div>
  59.         </div>
  60.       </div>
  61.       <a id="id2688113" class="indexterm"></a>
  62.       <a id="id2688128" class="indexterm"></a>
  63.       <p>
  64.     The <span class="guimenuitem">Selection Editor</span> command displays the
  65.     ‚Äú<span class="quote">Selection Editor</span>‚Äù dialog window. This dialog window
  66.     displays the active selection in the current image and gives you easy
  67.     access to the selection-related commands. It is not really intended for
  68.     editing selections directly, but if you are working on a selection, it
  69.     is handy to have the selection commands all together, since it is easier
  70.     to click on a button than to search for commands in the command tree of
  71.     the menubar. The ‚Äú<span class="quote">Selection Editor</span>‚Äù also offers some
  72.     advanced options for the ‚Äú<span class="quote">Select to Path</span>‚Äù command.
  73.   </p>
  74.       <div class="sect3" lang="en" xml:lang="en">
  75.         <div class="titlepage">
  76.           <div>
  77.             <div>
  78.               <h4 class="title"><a id="id2688169"></a>7.8.1.¬†
  79.       <span lang="en" xml:lang="en">Activating the Command</span>
  80.     </h4>
  81.             </div>
  82.           </div>
  83.         </div>
  84.         <div class="itemizedlist">
  85.           <ul type="disc">
  86.             <li>
  87.               <p>
  88.           You can access this command from the image menubar through
  89.           <span class="guimenu"><span class="accel">S</span>elect</span> ‚Üí <span class="guimenuitem"><span class="accel">S</span>election Editor</span>.
  90.         </p>
  91.             </li>
  92.           </ul>
  93.         </div>
  94.       </div>
  95.       <div class="sect3" lang="en" xml:lang="en">
  96.         <div class="titlepage">
  97.           <div>
  98.             <div>
  99.               <h4 class="title"><a id="id2688216"></a>7.8.2.¬†
  100.       <span lang="en" xml:lang="en">
  101.         Description of the ‚Äú<span class="quote">Selection Editor</span>‚Äù dialog window
  102.       </span>
  103.     </h4>
  104.             </div>
  105.           </div>
  106.         </div>
  107.         <div class="figure">
  108.           <a id="id2688233"></a>
  109.           <p class="title">
  110.             <b>Figure¬†15.42.¬†
  111.         <span lang="en" xml:lang="en">
  112.           The ‚Äú<span class="quote">Selection Editor</span>‚Äù dialog window
  113.         </span>
  114.       </b>
  115.           </p>
  116.           <div class="figure-contents">
  117.             <div class="mediaobject">
  118.               <img src="../images/menus/select-editor.png" alt="The Selection Editor dialog window" />
  119.             </div>
  120.           </div>
  121.         </div>
  122.         <br class="figure-break" />
  123.         <div class="variablelist">
  124.           <dl>
  125.             <dt>
  126.               <span class="term">The Buttons</span>
  127.             </dt>
  128.             <dd>
  129.               <p>
  130.             The ‚Äú<span class="quote">Selection Editor</span>‚Äù dialog window has several
  131.             buttons which you can use to easily access selection commands:
  132.           </p>
  133.               <div class="itemizedlist">
  134.                 <ul type="disc">
  135.                   <li>
  136.                     <p>
  137.                 The <a class="link" href="gimp-selection-all.html" title="7.2.¬† Select All">Select All</a>
  138.                 button.
  139.               </p>
  140.                   </li>
  141.                   <li>
  142.                     <p>
  143.                 The <a class="link" href="gimp-selection-none.html" title="7.3.¬† None">Select None</a>
  144.                 button.
  145.               </p>
  146.                   </li>
  147.                   <li>
  148.                     <p>
  149.                 The <a class="link" href="gimp-selection-invert.html" title="7.4.¬† Invert">Select Invert</a>
  150.                 button.
  151.               </p>
  152.                   </li>
  153.                   <li>
  154.                     <p>
  155.                 The <a class="link" href="gimp-selection-to-channel.html" title="7.16.¬† Save to Channel">Save to
  156.                 Channel</a> button.
  157.               </p>
  158.                   </li>
  159.                   <li>
  160.                     <p>
  161.                 The <a class="link" href="gimp-path-dialog.html#gimp-selection-to-path">To Path</a>
  162.                 button. If you hold the <span class="keycap"><strong>Shift</strong></span> key while
  163.                 clicking on this button, the ‚Äú<span class="quote">Advanced Settings</span>‚Äù
  164.                 dialog is displayed. Please see the next section for details
  165.                 about these options.
  166.               </p>
  167.                   </li>
  168.                   <li>
  169.                     <p>
  170.                 The <a class="link" href="gimp-selection-stroke.html" title="6.17.¬† Stroke Selection">Stroke
  171.                 Selection</a> button.
  172.               </p>
  173.                   </li>
  174.                 </ul>
  175.               </div>
  176.             </dd>
  177.             <dt>
  178.               <span class="term">The display window</span>
  179.             </dt>
  180.             <dd>
  181.               <p>
  182.             In the display window, selected areas of the image are white,
  183.             non-selected areas are black, and partially selected areas are
  184.             in shades of gray. Clicking in this window acts like
  185.             <a class="link" href="gimp-selection-by_color.html" title="7.6.¬† By Color">Select by Color</a>.
  186.             See the example below.
  187.           </p>
  188.             </dd>
  189.           </dl>
  190.         </div>
  191.         <div class="figure">
  192.           <a id="id2688446"></a>
  193.           <p class="title">
  194.             <b>Figure¬†15.43.¬†
  195.         <span lang="en" xml:lang="en">
  196.           Example of clicking in the ‚Äú<span class="quote">Selection Editor</span>‚Äù display
  197.           window
  198.         </span>
  199.       </b>
  200.           </p>
  201.           <div class="figure-contents">
  202.             <div class="mediaobject">
  203.               <img src="../images/menus/selection-editor-click.png" alt="Example of clicking in the Selection Editor display window" />
  204.               <div class="caption">
  205.                 <p>
  206.             Clicking in the ‚Äú<span class="quote">Selection Editor</span>‚Äù display window
  207.             to ‚Äú<span class="quote">Select By Color</span>‚Äù. Note that this figure could
  208.             just as well show the appearance of the
  209.             ‚Äú<span class="quote">Selection Editor</span>‚Äù display window when
  210.             ‚Äú<span class="quote">Select By Color</span>‚Äù is used in the image window.
  211.           </p>
  212.               </div>
  213.             </div>
  214.           </div>
  215.         </div>
  216.         <br class="figure-break" />
  217.       </div>
  218.       <div class="sect3" lang="en" xml:lang="en">
  219.         <div class="titlepage">
  220.           <div>
  221.             <div>
  222.               <h4 class="title"><a id="advanced-settings-for-selection-to-path"></a>7.8.3.¬†
  223.       <span lang="en" xml:lang="en">
  224.         The ‚Äú<span class="quote">Selection to Path Advanced Settings</span>‚Äù dialog
  225.       </span>
  226.     </h4>
  227.             </div>
  228.           </div>
  229.         </div>
  230.         <a id="id2688532" class="indexterm"></a>
  231.         <div class="figure">
  232.           <a id="id2688551"></a>
  233.           <p class="title">
  234.             <b>Figure¬†15.44.¬†
  235.         <span lang="en" xml:lang="en">
  236.           The ‚Äú<span class="quote">Advanced Settings</span>‚Äù dialog window
  237.         </span>
  238.       </b>
  239.           </p>
  240.           <div class="figure-contents">
  241.             <div class="mediaobject">
  242.               <img src="../images/menus/selection-to-path-adv.png" alt="The Advanced Settings dialog window" />
  243.             </div>
  244.           </div>
  245.         </div>
  246.         <br class="figure-break" />
  247.         <p>
  248.       The ‚Äú<span class="quote">Selection to Path Advanced Settings</span>‚Äù dialog
  249.       contains a number of options, most of which you can set with either
  250.       a slider bar or a text box. There is also one check box. These
  251.       options are mostly used by advanced users. They are:
  252.     </p>
  253.         <div class="itemizedlist">
  254.           <ul type="disc">
  255.             <li>
  256.               <p>
  257.           <span class="emphasis"><em>Align Threshold</em></span>:
  258.           If two endpoints are closer than this value, they are made to be
  259.           equal.
  260.         </p>
  261.             </li>
  262.             <li>
  263.               <p>
  264.           <span class="emphasis"><em>Corner Always Threshold</em></span>:
  265.           If the angle defined by a point and its predecessors
  266.           and successors is smaller than this, it is a corner,
  267.           even if it is within <span class="emphasis"><em>Corner Surround</em></span>
  268.           pixels of a point with a smaller angle.
  269.         </p>
  270.             </li>
  271.             <li>
  272.               <p>
  273.           <span class="emphasis"><em>Corner Surround</em></span>:
  274.           Number of points to consider when determining if a
  275.           point is a corner or not.
  276.         </p>
  277.             </li>
  278.             <li>
  279.               <p>
  280.           <span class="emphasis"><em>Corner Threshold</em></span>:
  281.           If a point, its predecessors, and its successors
  282.           define an angle smaller than this, it is a corner.
  283.         </p>
  284.             </li>
  285.             <li>
  286.               <p>
  287.           <span class="emphasis"><em>Error Threshold</em></span>:
  288.           Amount of error at which a fitted spline
  289.           <sup>[<a id="id2688671" href="#ftn.id2688671" class="footnote">6</a>]</sup>
  290.           is unacceptable. If any pixel is further away than this from the
  291.           fitted curve, the algorithm tries again.
  292.         </p>
  293.             </li>
  294.             <li>
  295.               <p>
  296.           <span class="emphasis"><em>Filter Alternative Surround</em></span>:
  297.           A second number of adjacent points to consider
  298.           when filtering.
  299.         </p>
  300.             </li>
  301.             <li>
  302.               <p>
  303.           <span class="emphasis"><em>Filter Epsilon</em></span>:
  304.           If the angles between the vectors produced by
  305.           <span class="emphasis"><em>Filter Surround</em></span> and
  306.           <span class="emphasis"><em>Filter Alternative Surround</em></span>
  307.           points differ by more than this, use the one from
  308.           <span class="emphasis"><em>Filter Alternative Surround</em></span>.
  309.         </p>
  310.             </li>
  311.             <li>
  312.               <p>
  313.           <span class="emphasis"><em>Filter Iteration Count</em></span>:
  314.           The number of times to smooth the original data points.
  315.           Increasing this number dramatically, to 50 or
  316.           so, can produce vastly better results.  But if
  317.           any points that ‚Äú<span class="quote">should</span>‚Äù be corners aren't found,
  318.           the curve goes wild around that point.
  319.         </p>
  320.             </li>
  321.             <li>
  322.               <p>
  323.           <span class="emphasis"><em>Filter Percent</em></span>: To produce the new point,
  324.           use the old point plus this times the neighbors.
  325.         </p>
  326.             </li>
  327.             <li>
  328.               <p>
  329.           <span class="emphasis"><em>Filter Secondary Surround</em></span>:
  330.           Number of adjacent points to consider if
  331.           <span class="emphasis"><em>Filter Surround</em></span> points defines a
  332.           straight line.
  333.         </p>
  334.             </li>
  335.             <li>
  336.               <p>
  337.           <span class="emphasis"><em>Filter Surround</em></span>:
  338.           Number of adjacent points to consider when filtering.
  339.         </p>
  340.             </li>
  341.             <li>
  342.               <p>
  343.           <span class="emphasis"><em>Keep Knees</em></span>:
  344.           This check box says whether or not to remove ‚Äú<span class="quote">knee</span>‚Äù
  345.           points after finding the outline.
  346.         </p>
  347.             </li>
  348.             <li>
  349.               <p>
  350.           <span class="emphasis"><em>Line Reversion Threshold</em></span>:
  351.           If a spline is closer to a straight line than this value,
  352.           it remains a straight line, even if it would otherwise
  353.           be changed back to a curve. This is weighted by the
  354.           square of the curve length, to make shorter curves
  355.           more likely to be reverted.
  356.         </p>
  357.             </li>
  358.             <li>
  359.               <p>
  360.           <span class="emphasis"><em>Line Threshold</em></span>:
  361.           How many pixels (on the average) a spline can
  362.           diverge from the line determined by its endpoints
  363.           before it is changed to a straight line.
  364.         </p>
  365.             </li>
  366.             <li>
  367.               <p>
  368.           <span class="emphasis"><em>Reparametrize Improvement</em></span>:
  369.           If reparameterization doesn't improve the fit by this
  370.           much percent, the algorithm stops doing it.
  371.         </p>
  372.             </li>
  373.             <li>
  374.               <p>
  375.           <span class="emphasis"><em>Reparametrize Threshold</em></span>:
  376.           Amount of error at which it is pointless to reparameterize.
  377.           This happens, for example, when the algorithm is trying to fit the
  378.           outline of the outside of an ‚Äú<span class="quote">O</span>‚Äù with a single spline.
  379.           The initial fit is not good enough for the Newton-Raphson
  380.           iteration to improve it.  It may be that it would be better
  381.           to detect the cases where the algorithm didn't find any corners.
  382.         </p>
  383.             </li>
  384.             <li>
  385.               <p>
  386.           <span class="emphasis"><em>Subdivide Search</em></span>:
  387.           Percentage of the curve away from the worst point
  388.           to look for a better place to subdivide.
  389.         </p>
  390.             </li>
  391.             <li>
  392.               <p>
  393.           <span class="emphasis"><em>Subdivide Surround</em></span>:
  394.           Number of points to consider when deciding whether
  395.           a given point is a better place to subdivide.
  396.         </p>
  397.             </li>
  398.             <li>
  399.               <p>
  400.           <span class="emphasis"><em>Subdivide Threshold</em></span>:
  401.           How many pixels a point can diverge from a straight
  402.           line and still be considered a better place to
  403.           subdivide.
  404.         </p>
  405.             </li>
  406.             <li>
  407.               <p>
  408.           <span class="emphasis"><em>Tangent Surround</em></span>:
  409.           Number of points to look at on either side of a
  410.           point when computing the approximation to the
  411.           tangent at that point.
  412.         </p>
  413.             </li>
  414.           </ul>
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  420.         <div class="footnote">
  421.           <p><sup>[<a id="ftn.id2688671" href="#id2688671" class="para">6</a>] </sup>
  422.               ‚Äú<span class="quote">Spline</span>‚Äù is a mathematical term for a
  423.               function which defines a curve by using a series of control
  424.               points, such as a B√©zier curve.
  425.               <div class="mediaobject"><img src="../images/menus/250px-Bezier.png" /></div>
  426.               See Wikipedia for more information.
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