GraphicsDevice (Java Platform SE 8 )
Keywords: java.awt.GraphicsDevice class
Date: 2016-12-09

java.awt

## Class GraphicsDevice

- java.lang.Object
- - java.awt.GraphicsDevice

-     public abstract class GraphicsDevice
      extends Object

  The `GraphicsDevice` class describes the graphics devices that might be available in a particular graphics environment. These include screen and printer devices. Note that there can be many screens and many printers in an instance of `GraphicsEnvironment`. Each graphics device has one or more `GraphicsConfiguration` objects associated with it. These objects specify the different configurations in which the `GraphicsDevice` can be used.

  In a multi-screen environment, the `GraphicsConfiguration` objects can be used to render components on multiple screens. The following code sample demonstrates how to create a `JFrame` object for each `GraphicsConfiguration` on each screen device in the `GraphicsEnvironment`:

         GraphicsEnvironment ge = GraphicsEnvironment.
         getLocalGraphicsEnvironment();
         GraphicsDevice[] gs = ge.getScreenDevices();
         for (int j = 0; j < gs.length; j++) {
            GraphicsDevice gd = gs[j];
            GraphicsConfiguration[] gc =
            gd.getConfigurations();
            for (int i=0; i < gc.length; i++) {
               JFrame f = new
               JFrame(gs[j].getDefaultConfiguration());
               Canvas c = new Canvas(gc[i]);
               Rectangle gcBounds = gc[i].getBounds();
               int xoffs = gcBounds.x;
               int yoffs = gcBounds.y;
               f.getContentPane().add(c);
               f.setLocation((i*50)+xoffs, (i*60)+yoffs);
               f.show();
            }
         }

  For more information on full-screen exclusive mode API, see the Full-Screen Exclusive Mode API Tutorial.

  See Also:
    `GraphicsEnvironment`, `GraphicsConfiguration`

- - ### Nested Class Summary

    Nested Classes
    Modifier and Type | Class and Description
    --- | ---
    `static class` | `GraphicsDevice.WindowTranslucency` Kinds of translucency supported by the underlying system.

  - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `static int` | `TYPE_IMAGE_BUFFER` Device is an image buffer.
    `static int` | `TYPE_PRINTER` Device is a printer.
    `static int` | `TYPE_RASTER_SCREEN` Device is a raster screen.

  - ### Constructor Summary

    Constructors
    Modifier | Constructor and Description
    --- | ---
    `protected` | `GraphicsDevice()` This is an abstract class that cannot be instantiated directly.

  - ### Method Summary

    All Methods Instance Methods Abstract Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `int` | `getAvailableAcceleratedMemory()` This method returns the number of bytes available in accelerated memory on this device.
    `GraphicsConfiguration` | `getBestConfiguration(GraphicsConfigTemplate gct)` Returns the "best" configuration possible that passes the criteria defined in the `GraphicsConfigTemplate`.
    `abstract GraphicsConfiguration[]` | `getConfigurations()` Returns all of the `GraphicsConfiguration` objects associated with this `GraphicsDevice`.
    `abstract GraphicsConfiguration` | `getDefaultConfiguration()` Returns the default `GraphicsConfiguration` associated with this `GraphicsDevice`.
    `DisplayMode` | `getDisplayMode()` Returns the current display mode of this `GraphicsDevice`.
    `DisplayMode[]` | `getDisplayModes()` Returns all display modes available for this `GraphicsDevice`.
    `Window` | `getFullScreenWindow()` Returns the `Window` object representing the full-screen window if the device is in full-screen mode.
    `abstract String` | `getIDstring()` Returns the identification string associated with this `GraphicsDevice`.
    `abstract int` | `getType()` Returns the type of this `GraphicsDevice`.
    `boolean` | `isDisplayChangeSupported()` Returns `true` if this `GraphicsDevice` supports low-level display changes.
    `boolean` | `isFullScreenSupported()` Returns `true` if this `GraphicsDevice` supports full-screen exclusive mode.
    `boolean` | `isWindowTranslucencySupported(GraphicsDevice.WindowTranslucency translucencyKind)` Returns whether the given level of translucency is supported by this graphics device.
    `void` | `setDisplayMode(DisplayMode dm)` Sets the display mode of this graphics device.
    `void` | `setFullScreenWindow(Window w)` Enter full-screen mode, or return to windowed mode.

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Field Detail

    - #### TYPE_RASTER_SCREEN

          public static final int TYPE_RASTER_SCREEN

      Device is a raster screen.
      See Also:
        Constant Field Values

    - #### TYPE_PRINTER

          public static final int TYPE_PRINTER

      Device is a printer.
      See Also:
        Constant Field Values

    - #### TYPE_IMAGE_BUFFER

          public static final int TYPE_IMAGE_BUFFER

      Device is an image buffer. This buffer can reside in device or system memory but it is not physically viewable by the user.
      See Also:
        Constant Field Values

  - ### Constructor Detail

    - #### GraphicsDevice

          protected GraphicsDevice()

      This is an abstract class that cannot be instantiated directly. Instances must be obtained from a suitable factory or query method.
      See Also:
        `GraphicsEnvironment.getScreenDevices()`, `GraphicsEnvironment.getDefaultScreenDevice()`, `GraphicsConfiguration.getDevice()`

  - ### Method Detail

    - #### getType

          public abstract int getType()

      Returns the type of this `GraphicsDevice`.
      Returns:
        the type of this `GraphicsDevice`, which can either be TYPE_RASTER_SCREEN, TYPE_PRINTER or TYPE_IMAGE_BUFFER.
      See Also:
        `TYPE_RASTER_SCREEN`, `TYPE_PRINTER`, `TYPE_IMAGE_BUFFER`

    - #### getIDstring

          public abstract String getIDstring()

      Returns the identification string associated with this `GraphicsDevice`.

      A particular program might use more than one `GraphicsDevice` in a `GraphicsEnvironment`. This method returns a `String` identifying a particular `GraphicsDevice` in the local `GraphicsEnvironment`. Although there is no public method to set this `String`, a programmer can use the `String` for debugging purposes. Vendors of the Java™ Runtime Environment can format the return value of the `String`. To determine how to interpret the value of the `String`, contact the vendor of your Java Runtime. To find out who the vendor is, from your program, call the `getProperty` method of the System class with "java.vendor".

      Returns:
        a `String` that is the identification of this `GraphicsDevice`.

    - #### getConfigurations

          public abstract GraphicsConfiguration[] getConfigurations()

      Returns all of the `GraphicsConfiguration` objects associated with this `GraphicsDevice`.
      Returns:
        an array of `GraphicsConfiguration` objects that are associated with this `GraphicsDevice`.

    - #### getDefaultConfiguration

          public abstract GraphicsConfiguration getDefaultConfiguration()

      Returns the default `GraphicsConfiguration` associated with this `GraphicsDevice`.
      Returns:
        the default `GraphicsConfiguration` of this `GraphicsDevice`.

    - #### getBestConfiguration

          public GraphicsConfiguration getBestConfiguration(GraphicsConfigTemplate gct)

      Returns the "best" configuration possible that passes the criteria defined in the `GraphicsConfigTemplate`.
      Parameters:
        `gct` - the `GraphicsConfigTemplate` object used to obtain a valid `GraphicsConfiguration`
      Returns:
        a `GraphicsConfiguration` that passes the criteria defined in the specified `GraphicsConfigTemplate`.
      See Also:
        `GraphicsConfigTemplate`

    - #### isFullScreenSupported

          public boolean isFullScreenSupported()

      Returns `true` if this `GraphicsDevice` supports full-screen exclusive mode. If a SecurityManager is installed, its `checkPermission` method will be called with `AWTPermission("fullScreenExclusive")`. `isFullScreenSupported` returns true only if that permission is granted.
      Returns:
        whether full-screen exclusive mode is available for this graphics device
      Since:
        1.4
      See Also:
        `AWTPermission`

    - #### setFullScreenWindow

          public void setFullScreenWindow(Window w)

      Enter full-screen mode, or return to windowed mode. The entered full-screen mode may be either exclusive or simulated. Exclusive mode is only available if `isFullScreenSupported` returns `true`.

      Exclusive mode implies:

      - Windows cannot overlap the full-screen window. All other application windows will always appear beneath the full-screen window in the Z-order.
      - There can be only one full-screen window on a device at any time, so calling this method while there is an existing full-screen Window will cause the existing full-screen window to return to windowed mode.
      - Input method windows are disabled. It is advisable to call `Component.enableInputMethods(false)` to make a component a non-client of the input method framework.

      The simulated full-screen mode places and resizes the window to the maximum possible visible area of the screen. However, the native windowing system may modify the requested geometry-related data, so that the `Window` object is placed and sized in a way that corresponds closely to the desktop settings.

      When entering full-screen mode, if the window to be used as a full-screen window is not visible, this method will make it visible. It will remain visible when returning to windowed mode.

      When entering full-screen mode, all the translucency effects are reset for the window. Its shape is set to `null`, the opacity value is set to 1.0f, and the background color alpha is set to 255 (completely opaque). These values are not restored when returning to windowed mode.

      It is unspecified and platform-dependent how decorated windows operate in full-screen mode. For this reason, it is recommended to turn off the decorations in a `Frame` or `Dialog` object by using the `setUndecorated` method.

      When returning to windowed mode from an exclusive full-screen window, any display changes made by calling `setDisplayMode` are automatically restored to their original state.

      Parameters:
        `w` - a window to use as the full-screen window; `null` if returning to windowed mode. Some platforms expect the fullscreen window to be a top-level component (i.e., a `Frame`); therefore it is preferable to use a `Frame` here rather than a `Window`.
      Since:
        1.4
      See Also:
        `isFullScreenSupported()`, `getFullScreenWindow()`, `setDisplayMode(java.awt.DisplayMode)`, `Component.enableInputMethods(boolean)`, `Component.setVisible(boolean)`, `Frame.setUndecorated(boolean)`, `Dialog.setUndecorated(boolean)`

    - #### getFullScreenWindow

          public Window getFullScreenWindow()

      Returns the `Window` object representing the full-screen window if the device is in full-screen mode.
      Returns:
        the full-screen window, or `null` if the device is not in full-screen mode.
      Since:
        1.4
      See Also:
        `setFullScreenWindow(Window)`

    - #### isDisplayChangeSupported

          public boolean isDisplayChangeSupported()

      Returns `true` if this `GraphicsDevice` supports low-level display changes. On some platforms low-level display changes may only be allowed in full-screen exclusive mode (i.e., if `isFullScreenSupported()` returns `true` and the application has already entered full-screen mode using `setFullScreenWindow(java.awt.Window)`).
      Returns:
        whether low-level display changes are supported for this graphics device.
      Since:
        1.4
      See Also:
        `isFullScreenSupported()`, `setDisplayMode(java.awt.DisplayMode)`, `setFullScreenWindow(java.awt.Window)`

    - #### setDisplayMode

          public void setDisplayMode(DisplayMode dm)

      Sets the display mode of this graphics device. This is only allowed if `isDisplayChangeSupported()` returns `true` and may require first entering full-screen exclusive mode using `setFullScreenWindow(java.awt.Window)` providing that full-screen exclusive mode is supported (i.e., `isFullScreenSupported()` returns `true`).

      The display mode must be one of the display modes returned by `getDisplayModes()`, with one exception: passing a display mode with `DisplayMode.REFRESH_RATE_UNKNOWN` refresh rate will result in selecting a display mode from the list of available display modes with matching width, height and bit depth. However, passing a display mode with `DisplayMode.BIT_DEPTH_MULTI` for bit depth is only allowed if such mode exists in the list returned by `getDisplayModes()`.

      Example code:

           Frame frame;
           DisplayMode newDisplayMode;
           GraphicsDevice gd;
           // create a Frame, select desired DisplayMode from the list of modes
           // returned by gd.getDisplayModes() ...

           if (gd.isFullScreenSupported()) {
               gd.setFullScreenWindow(frame);
           } else {
              // proceed in non-full-screen mode
              frame.setSize(...);
              frame.setLocation(...);
              frame.setVisible(true);
           }

           if (gd.isDisplayChangeSupported()) {
               gd.setDisplayMode(newDisplayMode);
           }

      Parameters:
        `dm` - The new display mode of this graphics device.
      Throws:
        `IllegalArgumentException` - if the `DisplayMode` supplied is `null`, or is not available in the array returned by `getDisplayModes`
        `UnsupportedOperationException` - if `isDisplayChangeSupported` returns `false`
      Since:
        1.4
      See Also:
        `getDisplayMode()`, `getDisplayModes()`, `isDisplayChangeSupported()`

    - #### getDisplayMode

          public DisplayMode getDisplayMode()

      Returns the current display mode of this `GraphicsDevice`. The returned display mode is allowed to have a refresh rate `DisplayMode.REFRESH_RATE_UNKNOWN` if it is indeterminate. Likewise, the returned display mode is allowed to have a bit depth `DisplayMode.BIT_DEPTH_MULTI` if it is indeterminate or if multiple bit depths are supported.
      Returns:
        the current display mode of this graphics device.
      Since:
        1.4
      See Also:
        `setDisplayMode(DisplayMode)`

    - #### getDisplayModes

          public DisplayMode[] getDisplayModes()

      Returns all display modes available for this `GraphicsDevice`. The returned display modes are allowed to have a refresh rate `DisplayMode.REFRESH_RATE_UNKNOWN` if it is indeterminate. Likewise, the returned display modes are allowed to have a bit depth `DisplayMode.BIT_DEPTH_MULTI` if it is indeterminate or if multiple bit depths are supported.
      Returns:
        all of the display modes available for this graphics device.
      Since:
        1.4

    - #### getAvailableAcceleratedMemory

          public int getAvailableAcceleratedMemory()

      This method returns the number of bytes available in accelerated memory on this device. Some images are created or cached in accelerated memory on a first-come, first-served basis. On some operating systems, this memory is a finite resource. Calling this method and scheduling the creation and flushing of images carefully may enable applications to make the most efficient use of that finite resource.
      Note that the number returned is a snapshot of how much memory is available; some images may still have problems being allocated into that memory. For example, depending on operating system, driver, memory configuration, and thread situations, the full extent of the size reported may not be available for a given image. There are further inquiry methods on the `ImageCapabilities` object associated with a VolatileImage that can be used to determine whether a particular VolatileImage has been created in accelerated memory.
      Returns:
        number of bytes available in accelerated memory. A negative return value indicates that the amount of accelerated memory on this GraphicsDevice is indeterminate.
      Since:
        1.4
      See Also:
        `Image.flush()`, `ImageCapabilities.isAccelerated()`

    - #### isWindowTranslucencySupported

          public boolean isWindowTranslucencySupported(GraphicsDevice.WindowTranslucency translucencyKind)

      Returns whether the given level of translucency is supported by this graphics device.
      Parameters:
        `translucencyKind` - a kind of translucency support
      Returns:
        whether the given translucency kind is supported
      Since:
        1.7

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