JavaTM 2 Platform
Std. Ed. v1.4.2

java.awt
Class GraphicsEnvironment

java.lang.Object
  extended byjava.awt.GraphicsEnvironment

public abstract class GraphicsEnvironment
extends Object

The GraphicsEnvironment class describes the collection of GraphicsDevice objects and Font objects available to a Java(tm) application on a particular platform. The resources in this GraphicsEnvironment might be local or on a remote machine. GraphicsDevice objects can be screens, printers or image buffers and are the destination of Graphics2D drawing methods. Each GraphicsDevice has a number of GraphicsConfiguration objects associated with it. These objects specify the different configurations in which the GraphicsDevice can be used.

See Also:
GraphicsDevice, GraphicsConfiguration

Constructor Summary
protected GraphicsEnvironment()
          This is an abstract class and cannot be instantiated directly.
 
Method Summary
abstract  Graphics2D createGraphics(BufferedImage img)
          Returns a Graphics2D object for rendering into the specified BufferedImage.
abstract  Font[] getAllFonts()
          Returns an array containing a one-point size instance of all fonts available in this GraphicsEnvironment.
abstract  String[] getAvailableFontFamilyNames()
          Returns an array containing the names of all font families available in this GraphicsEnvironment.
abstract  String[] getAvailableFontFamilyNames(Locale l)
          Returns an array containing the localized names of all font families available in this GraphicsEnvironment.
 Point getCenterPoint()
          Returns the Point where Windows should be centered.
abstract  GraphicsDevice getDefaultScreenDevice()
          Returns the default screen GraphicsDevice.
static GraphicsEnvironment getLocalGraphicsEnvironment()
          Returns the local GraphicsEnvironment.
 Rectangle getMaximumWindowBounds()
          Returns the maximum bounds for centered Windows.
abstract  GraphicsDevice[] getScreenDevices()
          Returns an array of all of the screen GraphicsDevice objects.
static boolean isHeadless()
          Tests whether or not a display, keyboard, and mouse can be supported in this environment.
 boolean isHeadlessInstance()
          Returns whether or not a display, keyboard, and mouse can be supported in this graphics environment.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

GraphicsEnvironment

protected GraphicsEnvironment()
This is an abstract class and cannot be instantiated directly. Instances must be obtained from a suitable factory or query method.

Method Detail

getLocalGraphicsEnvironment

public static GraphicsEnvironment getLocalGraphicsEnvironment()
Returns the local GraphicsEnvironment.

Returns:
the local GraphicsEnvironment

isHeadless

public static boolean isHeadless()
Tests whether or not a display, keyboard, and mouse can be supported in this environment. If this method returns true, a HeadlessException is thrown from areas of the Toolkit and GraphicsEnvironment that are dependent on a display, keyboard, or mouse.

Returns:
true if this environment cannot support a display, keyboard, and mouse; false otherwise
Since:
1.4
See Also:
HeadlessException

isHeadlessInstance

public boolean isHeadlessInstance()
Returns whether or not a display, keyboard, and mouse can be supported in this graphics environment. If this returns true, HeadlessException will be thrown from areas of the graphics environment that are dependent on a display, keyboard, or mouse.

Returns:
true if a display, keyboard, and mouse can be supported in this environment; false otherwise
Since:
1.4
See Also:
HeadlessException, isHeadless()

getScreenDevices

public abstract GraphicsDevice[] getScreenDevices()
                                           throws HeadlessException
Returns an array of all of the screen GraphicsDevice objects.

Returns:
an array containing all the GraphicsDevice objects that represent screen devices
Throws:
HeadlessException - if isHeadless() returns true
See Also:
isHeadless()

getDefaultScreenDevice

public abstract GraphicsDevice getDefaultScreenDevice()
                                               throws HeadlessException
Returns the default screen GraphicsDevice.

Returns:
the GraphicsDevice that represents the default screen device
Throws:
HeadlessException - if isHeadless() returns true
See Also:
isHeadless()

createGraphics

public abstract Graphics2D createGraphics(BufferedImage img)
Returns a Graphics2D object for rendering into the specified BufferedImage.

Parameters:
img - the specified BufferedImage
Returns:
a Graphics2D to be used for rendering into the specified BufferedImage

getAllFonts

public abstract Font[] getAllFonts()
Returns an array containing a one-point size instance of all fonts available in this GraphicsEnvironment. Typical usage would be to allow a user to select a particular font. Then, the application can size the font and set various font attributes by calling the deriveFont method on the choosen instance.

This method provides for the application the most precise control over which Font instance is used to render text. If a font in this GraphicsEnvironment has multiple programmable variations, only one instance of that Font is returned in the array, and other variations must be derived by the application.

If a font in this environment has multiple programmable variations, such as Multiple-Master fonts, only one instance of that font is returned in the Font array. The other variations must be derived by the application.

Returns:
an array of Font objects
Since:
1.2
See Also:
getAvailableFontFamilyNames(), Font, Font.deriveFont(int, float), Font.getFontName()

getAvailableFontFamilyNames

public abstract String[] getAvailableFontFamilyNames()
Returns an array containing the names of all font families available in this GraphicsEnvironment. Typical usage would be to allow a user to select a particular family name and allow the application to choose related variants of the same family when the user specifies style attributes such as Bold or Italic.

This method provides for the application some control over which Font instance is used to render text, but allows the Font object more flexibility in choosing its own best match among multiple fonts in the same font family.

Returns:
an array of String containing names of font families
Since:
1.2
See Also:
getAllFonts(), Font, Font.getFamily()

getAvailableFontFamilyNames

public abstract String[] getAvailableFontFamilyNames(Locale l)
Returns an array containing the localized names of all font families available in this GraphicsEnvironment. Typical usage would be to allow a user to select a particular family name and allow the application to choose related variants of the same family when the user specifies style attributes such as Bold or Italic.

This method provides for the application some control over which Font instance used to render text, but allows the Font object more flexibility in choosing its own best match among multiple fonts in the same font family. If l is null, this method returns an array containing all font family names available in this GraphicsEnvironment.

Parameters:
l - a Locale object that represents a particular geographical, political, or cultural region
Returns:
an array of String objects containing names of font families specific to the specified Locale
Since:
1.2
See Also:
getAllFonts(), Font, Font.getFamily()

getCenterPoint

public Point getCenterPoint()
                     throws HeadlessException
Returns the Point where Windows should be centered. It is recommended that centered Windows be checked to ensure they fit within the available display area using getMaximumWindowBounds().

Returns:
the point where Windows should be centered
Throws:
HeadlessException - if isHeadless() returns true
Since:
1.4
See Also:
getMaximumWindowBounds()

getMaximumWindowBounds

public Rectangle getMaximumWindowBounds()
                                 throws HeadlessException
Returns the maximum bounds for centered Windows. These bounds account for objects in the native windowing system such as task bars and menu bars. The returned bounds will reside on a single display with one exception: on multi-screen systems where Windows should be centered across all displays, this method returns the bounds of the entire display area.

To get the usable bounds of a single display, use GraphicsConfiguration.getBounds() and Toolkit.getScreenInsets().

Returns:
the maximum bounds for centered Windows
Throws:
HeadlessException - if isHeadless() returns true
Since:
1.4
See Also:
getCenterPoint(), GraphicsConfiguration.getBounds(), Toolkit.getScreenInsets(java.awt.GraphicsConfiguration)

JavaTM 2 Platform
Std. Ed. v1.4.2

Submit a bug or feature
For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

Copyright 2003 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.


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