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<page xmlns="http://projectmallard.org/1.0/"
      xmlns:its="http://www.w3.org/2005/11/its" type="task" style="task"
      id="zoom_preview">

  <info>
    <link type="guide" xref="index#main"/>
    <include xmlns="http://www.w3.org/2001/XInclude" href="legal.xml"/>
    <credit type="author">
      <name its:translate="no">Romain F. T.</name>
      <email its:translate="no">rrroschan@gmail.com</email>
    </credit>
    <desc>Zoom level, scrolling, and the preview thumbnail.</desc>
  </info>

  <title>Zooming and scrolling</title>

  <p>In the bottom bar, the <gui style="button">Preview</gui> button
  (available with <link xref="tools_classic">most tools</link>) displays the
  current zoom level.</p>
  <p>Clicking on this button opens a menu with a thumbnail of the full picture
  you're editing, along with zoom level controls.</p>

  <section>
    <title>Moving the view</title>

    <media type="image" mime="image/png" width="80%" its:translate="no"
           src="figures/screenshot_zoom.png" />

    <p>You may use the thumbnail preview to move the view within a huge image,
    but it's not the simplest way to do it:</p>
    <p>Aside of the scrollbars, using keyboard shortcuts, touch gestures, or
    sliding with the mouse middle-click, might be more efficient.</p>
  </section>

  <section>
    <title>Zooming in or out</title>

    <p>You can use the thumbnail preview controls to change the zoom level, but
    you can also use keyboard shortcuts, touch gestures, or you can scroll while
    pressing the <key>Ctrl</key> key. This behavior can be changed:</p>
  </section>

  <section id="configuration">
    <title>Configuration</title>

    <p>In <link xref="preferences">the app preferences</link>, you can set how
    you want to zoom on the image: by default, scrolling on the canvas <em>moves
    the current view</em> in the direction of the scrolling, and scrolling while
    holding the <key>Ctrl</key> key <em>zooms in or out</em>. You can turn off
    the switch to invert these behaviors.</p>

    <p>If you rely on an old-school mouse, it's pertinent to turn this setting
    off: the mouse wheel will then directly zoom in and out. To browse the
    image, you can move your mouse on the canvas while you hold its middle
    button: it'll to move the current view in any direction.</p>

    <p>If you have a trackpad, or a touchscreen, it's recommended to keep using
    the <key>Ctrl</key> key to zoom (default behavior): with such a device,
    you're able to intuitively scroll in both directions to browse the entire
    image. If your device supports multi-touch gestures, you'll even be able to
    zoom in and out using the default <em>touch gestures (stretch or pinch with
    two fingers)</em>, which will not work if you turn off this setting.</p>
    <p>Of course, it's always possible to control the zoom level with the
    keyboard shortcuts, or the buttons under the thumbnail preview.</p>
  </section>

</page>

