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  4.   <head>
  5.     <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
  6.     <title>9.14.¬† Scale Image</title>
  7.     <link rel="stylesheet" href="gimp-help-plain.css" type="text/css" />
  8.     <link rel="stylesheet" href="gimp-help-screen.css" type="text/css" />
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  12.     <link rel="start" href="index.html" title="GNU Image Manipulation Program" />
  13.     <link rel="up" href="gimp-imagewindow-menus-image.html" title="9.¬† The ‚ÄúImage‚Äù Menu" />
  14.     <link rel="prev" href="gimp-image-print-size.html" title="9.13.¬† Print Size" />
  15.     <link rel="next" href="gimp-image-crop.html" title="9.15.¬† Crop to Selection" />
  16.   </head>
  17.   <body>
  18.     <div class="navheader">
  19.       <table width="100%" summary="Navigation header">
  20.         <tr>
  21.           <th colspan="3" align="center">9.14.¬†
  22.     <span lang="en" xml:lang="en">Scale Image</span>
  23.   </th>
  24.         </tr>
  25.         <tr>
  26.           <td width="20%" align="left"><a accesskey="p" href="gimp-image-print-size.html"><img src="../images/prev.png" alt="Prev" /></a>¬†</td>
  27.           <th width="60%" align="center">9.¬†
  28.     <span lang="en" xml:lang="en">The ‚Äú<span class="quote">Image</span>‚Äù Menu</span>
  29.   </th>
  30.           <td width="20%" align="right">¬†<a accesskey="n" href="gimp-image-crop.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-image-scale"></a>9.14.¬†
  40.     <span lang="en" xml:lang="en">Scale Image</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: 2336 $</td>
  53.                   <td align="left">2006-08-07</td>
  54.                   <td align="left">scb</td>
  55.                 </tr>
  56.               </table>
  57.             </div>
  58.           </div>
  59.         </div>
  60.       </div>
  61.       <a id="id2699361" class="indexterm"></a>
  62.       <p>
  63.     The <span class="guimenuitem">Scale Image</span> command enlarges or reduces
  64.     the physical size of the image by changing the number of pixels it
  65.     contains. It changes the size of the contents of the image and resizes
  66.     the canvas accordingly.
  67.   </p>
  68.       <p>
  69.     It operates on the entire image. If your image has layers of different
  70.     sizes, making the image smaller could shrink some of them down to nothing,
  71.     since a layer cannot be less than one pixel wide or high. If this happens,
  72.     you will be warned before the operation is performed.
  73.   </p>
  74.       <p>
  75.     If you only want to scale a particular layer, use the
  76.     <a class="link" href="gimp-layer-scale.html" title="10.50.¬† Scale Layer">Scale Layer</a> command.
  77.   </p>
  78.       <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
  79.         <table border="0" summary="Note">
  80.           <tr>
  81.             <td rowspan="2" align="center" valign="top" width="25">
  82.               <img alt="[Note]" src="../images/note.png" />
  83.             </td>
  84.             <th align="left"><a id="gimp-image-scale-warning"></a>Note</th>
  85.           </tr>
  86.           <tr>
  87.             <td align="left" valign="top">
  88.               <p>
  89.       If scaling would produce an image larger than the
  90.       ‚Äú<span class="quote">Maximum new image size</span>‚Äù set in the
  91.       <a class="link" href="gimp-pimping.html#gimp-prefs-environment" title="1.2.¬† Environment">Environment</a> page of the
  92.       Preferences dialog (which has a default of 64Mb), you are warned and
  93.       asked to confirm the operation before it is performed. You may not
  94.       experience any problems if you confirm the operation, but you should
  95.       be aware that very large images consume a lot of resources and
  96.       extremely large images may take more resources than you have,
  97.       causing <acronym class="acronym">GIMP</acronym> to crash or not perform well.
  98.     </p>
  99.             </td>
  100.           </tr>
  101.         </table>
  102.       </div>
  103.       <div class="sect3" lang="en" xml:lang="en">
  104.         <div class="titlepage">
  105.           <div>
  106.             <div>
  107.               <h4 class="title"><a id="id2699446"></a>9.14.1.¬†
  108.       <span lang="en" xml:lang="en">Activate the Command</span>
  109.     </h4>
  110.             </div>
  111.           </div>
  112.         </div>
  113.         <div class="itemizedlist">
  114.           <ul type="disc">
  115.             <li>
  116.               <p>
  117.           You can access this command from the image menubar through
  118.           <span class="guimenu"><span class="accel">I</span>mage</span> ‚Üí <span class="guimenuitem"><span class="accel">S</span>cale image</span>.
  119.         </p>
  120.             </li>
  121.           </ul>
  122.         </div>
  123.       </div>
  124.       <div class="sect3" lang="en" xml:lang="en">
  125.         <div class="titlepage">
  126.           <div>
  127.             <div>
  128.               <h4 class="title"><a id="id2699494"></a>9.14.2.¬†
  129.       <span lang="en" xml:lang="en">
  130.         The ‚Äú<span class="quote">Scale Image</span>‚Äù Dialog
  131.       </span>
  132.     </h4>
  133.             </div>
  134.           </div>
  135.         </div>
  136.         <div class="figure">
  137.           <a id="id2699509"></a>
  138.           <p class="title">
  139.             <b>Figure¬†15.80.¬†
  140.         <span lang="en" xml:lang="en">
  141.           The
  142.           ‚Äú<span class="quote">Scale Image</span>‚Äù
  143.           dialog
  144.         </span>
  145.       </b>
  146.           </p>
  147.           <div class="figure-contents">
  148.             <div class="mediaobject">
  149.               <img src="../images/dialogs/scale-image.png" alt="The Scale Image dialog" />
  150.             </div>
  151.           </div>
  152.         </div>
  153.         <br class="figure-break" />
  154.         <div class="variablelist">
  155.           <dl>
  156.             <dt>
  157.               <span class="term">Image Size</span>
  158.             </dt>
  159.             <dd>
  160.               <p>
  161.             You should keep in mind that an image can be located in one of
  162.             four places: in the image file, in RAM after it has been loaded,
  163.             on your screen when it is displayed, or on paper after it has been
  164.             printed. Scaling the image changes the number of pixels (the
  165.             amount of information) the image contains, so it directly affects
  166.             the amount of memory the image needs (in RAM or in a file).
  167.           </p>
  168.               <p>
  169.             However printing size also depends upon the resolution of the
  170.             image, which essentially determines how many pixels there will
  171.             be on each inch of paper. If you want to change the printing
  172.             size without scaling the image and changing the number of pixels
  173.             in it, you should use the
  174.             <a class="link" href="gimp-image-print-size.html" title="9.13.¬† Print Size">Print Size</a> dialog.
  175.             The screen size depends not only on the number of pixels, but
  176.             also on the screen resolution, the zoom factor and the setting
  177.             of the <a class="link" href="gimp-view-dot-for-dot.html" title="8.3.¬† Dot for Dot">Dot for Dot</a>
  178.             option.
  179.           </p>
  180.               <div class="variablelist">
  181.                 <dl>
  182.                   <dt>
  183.                     <span class="term">Width; Height</span>
  184.                   </dt>
  185.                   <dd>
  186.                     <p>
  187.                   When you click on the <span class="guimenuitem">Scale</span>
  188.                   command, the dialog displays the dimensions of the
  189.                   original image in pixels. You can set the
  190.                   <span class="guilabel">Width</span> and the
  191.                   <span class="guilabel">Height</span> you want to give to your
  192.                   image by adding or removing pixels. If the chain icon next
  193.                   to the Width and Height boxes is unbroken, the Width and
  194.                   Height will stay in the same proportion to each other. If
  195.                   you break the chain by clicking on it, you can set them
  196.                   independently, but this will distort the image.
  197.                 </p>
  198.                     <p>
  199.                   However, you do not have to set the dimensions in pixels.
  200.                   You can choose different units from the drop-down menu.
  201.                   If you choose percent as the units, you can set the image
  202.                   size relative to its original size. You can also use
  203.                   physical units, such as inches or millimeters. If you do
  204.                   that, you should set the <span class="guilabel">X resolution</span>
  205.                   and <span class="guilabel">Y resolution</span> fields to
  206.                   appropriate values, because they are used to convert
  207.                   between physical units and image dimensions in pixels.
  208.                 </p>
  209.                     <p>
  210.                   If you enlarge an image beyond its original size,
  211.                   <acronym class="acronym">GIMP</acronym> calculates the missing
  212.                   pixels by interpolation, but it does not add any new
  213.                   detail. The more you enlarge an image, the more blurred
  214.                   it becomes. The appearance of an enlarged image depends
  215.                   upon the interpolation method you choose. You may improve
  216.                   the appearance by using the
  217.                   <a class="link" href="plug-in-sharpen.html" title="5.8.¬† Sharpen">Sharpen</a> filter
  218.                   after you have scaled an image, but it is best to
  219.                   use high resolution when you scan, take digital
  220.                   photographs or produce digital images by other means.
  221.                   Raster images inherently do not scale up well.
  222.                 </p>
  223.                     <p>
  224.                   You may need to reduce your image if you intend to use it on
  225.                   a web page. You have to consider that most internet users
  226.                   have relatively small screens which cannot completely
  227.                   display a large image. Many screens have a resolution of
  228.                   1024x768 or even less.
  229.                 </p>
  230.                     <p>
  231.                   Adding or removing pixels is called
  232.                   ‚Äú<span class="quote">Resampling</span>‚Äù.
  233.                 </p>
  234.                   </dd>
  235.                   <dt>
  236.                     <span class="term">X resolution; Y resolution</span>
  237.                   </dt>
  238.                   <dd>
  239.                     <p>
  240.                   You can set the printing resolution for the image in the
  241.                   <span class="guilabel">X resolution</span>
  242.                   and <span class="guilabel">Y resolution</span>
  243.                   fields. You can also change the units of measurement by
  244.                   using the drop-down menu.
  245.                 </p>
  246.                   </dd>
  247.                 </dl>
  248.               </div>
  249.             </dd>
  250.             <dt>
  251.               <span class="term">Quality</span>
  252.             </dt>
  253.             <dd>
  254.               <p>
  255.             To change the image size, either some pixels have to be removed
  256.             or new pixels must be added. The process you use determines the
  257.             quality of the result. The <span class="guilabel">Interpolation</span>
  258.             drop down list provides a selection of available methods of
  259.             interpolating the color of pixels in a scaled image:
  260.           </p>
  261.               <div class="variablelist">
  262.                 <dl>
  263.                   <dt>
  264.                     <span class="term">Interpolation</span>
  265.                   </dt>
  266.                   <dd>
  267.                     <div class="itemizedlist">
  268.                       <ul type="disc">
  269.                         <li>
  270.                           <p>
  271.                       <span class="guilabel">None</span>:
  272.                       No interpolation is used. Pixels are simply enlarged
  273.                       or removed, as they are when zooming. This method is low
  274.                       quality, but very fast.
  275.                     </p>
  276.                         </li>
  277.                         <li>
  278.                           <p>
  279.                       <span class="guilabel">Linear</span>: This method is relatively
  280.                       fast, but still provides fairly good results.
  281.                     </p>
  282.                         </li>
  283.                         <li>
  284.                           <p>
  285.                       <span class="guilabel">Cubic</span>:
  286.                       The method that produces the best results, but also
  287.                       the slowest method.
  288.                     </p>
  289.                         </li>
  290.                         <li>
  291.                           <p>
  292.                       <span class="guilabel">Sinc (Lanczos 3)</span>: New with
  293.                       GIMP-2.4, this method gives less blur in important
  294.                       resizings.
  295.                     </p>
  296.                         </li>
  297.                       </ul>
  298.                     </div>
  299.                   </dd>
  300.                 </dl>
  301.               </div>
  302.             </dd>
  303.           </dl>
  304.         </div>
  305.         <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
  306.           <table border="0" summary="Note">
  307.             <tr>
  308.               <td rowspan="2" align="center" valign="top" width="25">
  309.                 <img alt="[Note]" src="../images/note.png" />
  310.               </td>
  311.               <th align="left">Note</th>
  312.             </tr>
  313.             <tr>
  314.               <td align="left" valign="top">
  315.                 <p>
  316.         See also the <a class="link" href="gimp-tool-scale.html" title="4.6.¬† Scale">Scale tool</a>,
  317.         which lets you scale a layer, a selection or a path.
  318.       </p>
  319.               </td>
  320.             </tr>
  321.           </table>
  322.         </div>
  323.       </div>
  324.     </div>
  325.     <div class="navfooter">
  326.       <hr />
  327.       <table width="100%" summary="Navigation footer">
  328.         <tr>
  329.           <td width="40%" align="left"><a accesskey="p" href="gimp-image-print-size.html"><img src="../images/prev.png" alt="Prev" /></a>¬†</td>
  330.           <td width="20%" align="center">
  331.             <a accesskey="u" href="gimp-imagewindow-menus-image.html">
  332.               <img src="../images/up.png" alt="Up" />
  333.             </a>
  334.           </td>
  335.           <td width="40%" align="right">¬†<a accesskey="n" href="gimp-image-crop.html"><img src="../images/next.png" alt="Next" /></a></td>
  336.         </tr>
  337.         <tr>
  338.           <td width="40%" align="left" valign="top"><a accesskey="p" href="gimp-image-print-size.html">9.13.¬†
  339.     <span lang="en" xml:lang="en">Print Size</span>
  340.   </a>¬†</td>
  341.           <td width="20%" align="center">
  342.             <a accesskey="h" href="index.html">
  343.               <img src="../images/home.png" alt="Home" />
  344.             </a>
  345.           </td>
  346.           <td width="40%" align="right" valign="top">¬†<a accesskey="n" href="gimp-image-crop.html">9.15.¬†
  347.     <span lang="en" xml:lang="en">Crop to Selection</span>
  348.   </a></td>
  349.         </tr>
  350.       </table>
  351.     </div>
  352.   </body>
  353. </html>
  354.