getvolmem.html

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<TITLE>Getting Amount of Free Accelerated Image Memory
(Java Developers Almanac Example)
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  <h3>
    e677.  
    Getting Amount of Free Accelerated Image Memory</h3>

Images in accelerated memory are much faster to draw on the screen.
However, accelerated memory is typically limited and it is usually
necessary for an application to manage the images residing in this
space.  This example demonstrates how to determine the amount free
accelerated available.

<P> Note: There appears to be a problem with
<code>GraphicsDevice.getAvailableAcceleratedMemory()</code> on some systems.
The method returns 0 even if accelerated image memory is available.  A
workaround is to create a temporary volatile image on the graphics
device before calling the method.  Once the volatile image is created,
the method appears to return the correct value on all subsequent
calls.

<P> See also <a href="../java.awt/screen_FullWin.html" class="eglink"><font size="-1"><b>e605</b> Enabling Full-Screen Mode</font></a> and
<a href="../java.awt.image/VolImage.html" class="eglink"><font size="-1"><b>e678</b> Creating and Drawing an Accelerated Image</font></a>.


<pre>
    GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
    try {
        GraphicsDevice[] gs = ge.getScreenDevices();
    
        // Get current amount of available memory in bytes for each screen
        for (int i=0; i&lt;gs.length; i++) {
            // Workaround; see description
            VolatileImage im = gs[i].getDefaultConfiguration().createCompatibleVolatileImage(1, 1);
    
            // Retrieve available free accelerated image memory
            int bytes = gs[i].getAvailableAcceleratedMemory();
            if (bytes &lt; 0) {
                // Amount of memory is unlimited
            }
    
            // Release the temporary volatile image
            im.flush();
        }
    } catch (HeadlessException e) {
        // Is thrown if there are no screen devices
    }
</pre>
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            &nbsp;Related Examples
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e678. <a class="eglink" href="VolImage.html?l=rel">
    Creating and Drawing an Accelerated Image
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        See also: 
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    Buffered Images
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    Effects
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<a class="eglink" href="/egs/java.awt.image/pkg.html?l=rel#Images">
    Images
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