docs/html/tools/help/draw9patch.jd

page.title=Draw 9-patch
page.tags=NinePatch
@jd:body

<p>The Draw 9-patch tool is a WYSIWYG editor that allows you to create bitmap images that
automatically resize to accommodate the contents of the view and the size of the screen. Selected
parts of the image are scaled horizontally or vertically based indicators drawn within the image. </p>
<p>For an introduction to NinePatch graphics and how they work, please read
the section about NinePatch Drawables in the
<a href="{@docRoot}guide/topics/graphics/2d-graphics.html#nine-patch">Canvas and Drawables</a>
document.</p>

<img src="{@docRoot}images/draw9patch-norm.png" style="float:right" alt="" height="300" width="341"
/>

<p>Here's a quick guide to create a NinePatch graphic using the Draw 9-patch tool.
You'll need the PNG image with which you'd like to create a NinePatch image.</p>

<ol>
  <li>From a terminal, run the <code>draw9patch</code> command from your SDK
    <code>sdk/tools</code> directory to launch the Draw 9-patch tool. 
    </li>
  <li>Drag your PNG image into the Draw 9-patch window
    (or <strong>File</strong> > <strong>Open 9-patch...</strong> to locate the file).
    Your workspace will now open.
    <p>The left pane is your drawing area, in which you can edit the lines for the
     stretchable patches and content area. The right
     pane is the preview area, where you can preview your graphic when stretched.</p>
    </li>
  <li>Click within the 1-pixel perimeter to draw the lines that define the stretchable
    patches and (optional) content area. Right-click (or hold Shift and click, on Mac) to erase
    previously drawn lines.
    </li>
  <li>When done, select <strong>File</strong> > <strong>Save 9-patch...</strong>
    <p>Your image will be saved with the <code>.9.png</code> file name.</p>
    </li>
</ol>

   <p>To make sure that your NinePatch graphics scale down properly, verify that any
   stretchable regions are at least 2x2 pixels in size.
   Otherwise, they may disappear when scaled down. Also, provide one pixel of extra safe space in
   the graphics before and after stretchable regions to avoid interpolation during scaling that may
   cause the color at the boundaries to change. </p>

    <p class="note"><strong>Note:</strong> A normal PNG file (<code>*.png</code>) will be
     loaded with an empty one-pixel border added around the image, in which you can draw
     the stretchable patches and content area.
     A previously saved NinePatch file (<code>*.9.png</code>) will be loaded as-is,
     with no drawing area added, because it already exists.</p>

<img src="{@docRoot}images/draw9patch-bad.png" style="float:right;clear:both" alt="" height="300" width="341"
/>

<p>Optional controls include:</p>
<ul>
  <li><strong>Zoom</strong>: Adjust the zoom level of the graphic in the drawing area.</li>
  <li><strong>Patch scale</strong>: Adjust the scale of the images in the preview area.</li>
  <li><strong>Show lock</strong>: Visualize the non-drawable area of the graphic on mouse-over.</li>
  <li><strong>Show patches</strong>: Preview the stretchable patches in the drawing area (pink is a 
    stretchable patch).</li>
  <li><strong>Show content</strong>: Highlight the content area in the preview images 
    (purple is the area in which content is allowed).</li>
  <li><strong>Show bad patches</strong>: Adds a red border around patch areas that may
  produce artifacts in the graphic when stretched. Visual coherence of your stretched
  image will be maintained if you eliminate all bad patches.</li>
<ul>