Class GraphicsEnvironment
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:
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Constructor Summary
ConstructorsModifierConstructorDescriptionprotectedThis is an abstract class and cannot be instantiated directly. -
Method Summary
Modifier and TypeMethodDescriptionabstract Graphics2DReturns aGraphics2Dobject for rendering into the specifiedBufferedImage.abstract Font[]Returns an array containing a one-point size instance of all fonts available in thisGraphicsEnvironment.abstract String[]Returns an array containing the names of all font families in thisGraphicsEnvironmentlocalized for the default locale, as returned byLocale.getDefault().abstract String[]Returns an array containing the names of all font families in thisGraphicsEnvironmentlocalized for the specified locale.Returns the Point where Windows should be centered.abstract GraphicsDeviceReturns the default screenGraphicsDevice.static GraphicsEnvironmentReturns the localGraphicsEnvironment.Returns the maximum bounds for centered Windows.abstract GraphicsDevice[]Returns an array of all of the screenGraphicsDeviceobjects.static booleanTests whether or not a display, keyboard, and mouse can be supported in this environment.booleanReturns whether or not a display, keyboard, and mouse can be supported in this graphics environment.voidIndicates a preference for locale-specific fonts in the mapping of logical fonts to physical fonts.voidIndicates a preference for proportional over non-proportional (for example dual-spaced CJK fonts) fonts in the mapping of logical fonts to physical fonts.booleanregisterFont(Font font) Registers a createdFontin thisGraphicsEnvironment.
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Constructor Details
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GraphicsEnvironment
protected GraphicsEnvironment()This is an abstract class and cannot be instantiated directly. Instances must be obtained from a suitable factory or query method.
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Method Details
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getLocalGraphicsEnvironment
Returns the localGraphicsEnvironment.- Returns:
- the local
GraphicsEnvironment
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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:
trueif this environment cannot support a display, keyboard, and mouse;falseotherwise- Since:
- 1.4
- See Also:
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isHeadlessInstance
public boolean isHeadlessInstance()Returns whether or not a display, keyboard, and mouse can be supported in this graphics environment. If this returns true,HeadlessExceptionwill be thrown from areas of the graphics environment that are dependent on a display, keyboard, or mouse.- Returns:
trueif a display, keyboard, and mouse can be supported in this environment;falseotherwise- Since:
- 1.4
- See Also:
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getScreenDevices
Returns an array of all of the screenGraphicsDeviceobjects.- Returns:
- an array containing all the
GraphicsDeviceobjects that represent screen devices - Throws:
HeadlessException- if isHeadless() returns true- See Also:
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getDefaultScreenDevice
Returns the default screenGraphicsDevice.- Returns:
- the
GraphicsDevicethat represents the default screen device - Throws:
HeadlessException- if isHeadless() returns true- See Also:
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createGraphics
Returns aGraphics2Dobject for rendering into the specifiedBufferedImage.- Parameters:
img- the specifiedBufferedImage- Returns:
- a
Graphics2Dto be used for rendering into the specifiedBufferedImage - Throws:
NullPointerException- ifimgis null
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getAllFonts
Returns an array containing a one-point size instance of all fonts available in thisGraphicsEnvironment. 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 thederiveFontmethod on the chosen instance.This method provides for the application the most precise control over which
Fontinstance is used to render text. If a font in thisGraphicsEnvironmenthas multiple programmable variations, only one instance of thatFontis 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
Fontarray. The other variations must be derived by the application.- Returns:
- an array of
Fontobjects - Since:
- 1.2
- See Also:
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getAvailableFontFamilyNames
Returns an array containing the names of all font families in thisGraphicsEnvironmentlocalized for the default locale, as returned byLocale.getDefault().Typical usage would be for presentation to a user for selection of a particular family name. An application can then specify this name when creating a font, in conjunction with a style, such as bold or italic, giving the font system flexibility in choosing its own best match among multiple fonts in the same font family.
- Returns:
- an array of
Stringcontaining font family names localized for the default locale, or a suitable alternative name if no name exists for this locale. - Since:
- 1.2
- See Also:
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getAvailableFontFamilyNames
Returns an array containing the names of all font families in thisGraphicsEnvironmentlocalized for the specified locale.Typical usage would be for presentation to a user for selection of a particular family name. An application can then specify this name when creating a font, in conjunction with a style, such as bold or italic, giving the font system flexibility in choosing its own best match among multiple fonts in the same font family.
- Parameters:
l- aLocaleobject that represents a particular geographical, political, or cultural region. Specifyingnullis equivalent to specifyingLocale.getDefault().- Returns:
- an array of
Stringcontaining font family names localized for the specifiedLocale, or a suitable alternative name if no name exists for the specified locale. - Since:
- 1.2
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registerFont
Registers a createdFontin thisGraphicsEnvironment. A created font is one that was returned from callingFont.createFont(int, java.io.InputStream), or derived from a created font by callingFont.deriveFont(int, float). After calling this method for such a font, it is available to be used in constructing newFonts by name or family name, and is enumerated bygetAvailableFontFamilyNames()andgetAllFonts()within the execution context of this application or applet. This means applets cannot register fonts in a way that they are visible to other applets.Reasons that this method might not register the font and therefore return
falseare:- The font is not a created
Font. - The font conflicts with a non-created
Fontalready in thisGraphicsEnvironment. For example if the name is that of a system font, or a logical font as described in the documentation of theFontclass. It is implementation dependent whether a font may also conflict if it has the same family name as a system font.Notice that an application can supersede the registration of an earlier created font with a new one.
- Parameters:
font- the font to be registered- Returns:
- true if the
fontis successfully registered in thisGraphicsEnvironment. - Throws:
NullPointerException- iffontis null- Since:
- 1.6
- The font is not a created
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preferLocaleFonts
public void preferLocaleFonts()Indicates a preference for locale-specific fonts in the mapping of logical fonts to physical fonts. Calling this method indicates that font rendering should primarily use fonts specific to the primary writing system (the one indicated by the default encoding and the initial default locale). For example, if the primary writing system is Japanese, then characters should be rendered using a Japanese font if possible, and other fonts should only be used for characters for which the Japanese font doesn't have glyphs.The actual change in font rendering behavior resulting from a call to this method is implementation dependent; it may have no effect at all, or the requested behavior may already match the default behavior. The behavior may differ between font rendering in lightweight and peered components. Since calling this method requests a different font, clients should expect different metrics, and may need to recalculate window sizes and layout. Therefore this method should be called before user interface initialisation.
- Since:
- 1.5
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preferProportionalFonts
public void preferProportionalFonts()Indicates a preference for proportional over non-proportional (for example dual-spaced CJK fonts) fonts in the mapping of logical fonts to physical fonts. If the default mapping contains fonts for which proportional and non-proportional variants exist, then calling this method indicates the mapping should use a proportional variant.The actual change in font rendering behavior resulting from a call to this method is implementation dependent; it may have no effect at all. The behavior may differ between font rendering in lightweight and peered components. Since calling this method requests a different font, clients should expect different metrics, and may need to recalculate window sizes and layout. Therefore this method should be called before user interface initialisation.
- Since:
- 1.5
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getCenterPoint
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:
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getMaximumWindowBounds
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()andToolkit.getScreenInsets().- Returns:
- the maximum bounds for centered Windows
- Throws:
HeadlessException- if isHeadless() returns true- Since:
- 1.4
- See Also:
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