OpenJDK 27 · java.awt.GraphicsEnvironment · APIdia, the JavaDoc alternative

Modifier and Type	Class and Description
private static class	GraphicsEnvironment.LocalGE Lazy initialization of local graphics environment using holder idiom.

Modifier and Type	Field and Description
private static Boolean	defaultHeadless The headless state assumed by default
private static Boolean	headless The headless state of the Toolkit and GraphicsEnvironment

Access	Constructor and Description
protected	GraphicsEnvironment() This is an abstract class and cannot be instantiated directly.

Method Summary

Modifier and Type	Method and Description
pack-priv static void	checkHeadless() Check for headless state and throw HeadlessException if headless
public abstract Graphics2D	Returns: a `Graphics2D` to be used for rendering into the specified `BufferedImage` createGraphics(BufferedImage the specified `BufferedImage` img) Returns a `Graphics2D` object for rendering into the specified `BufferedImage`.
public abstract Font[]	Returns: an array of `Font` objects getAllFonts() Returns an array containing a one-point size instance of all fonts available in this `GraphicsEnvironment`.
public abstract String[]	Returns: an array of `String` containing font family names localized for the default locale, or a suitable alternative name if no name exists for this locale. getAvailableFontFamilyNames() Returns an array containing the names of all font families in this `GraphicsEnvironment` localized for the default locale, as returned by `Locale.getDefault()`.
public abstract String[]	Returns: an array of `String` containing font family names localized for the specified `Locale`, or a suitable alternative name if no name exists for the specified locale. getAvailableFontFamilyNames(Locale a `Locale` object that represents a particular geographical, political, or cultural region. Specifying `null` is equivalent to specifying `Locale.getDefault()`. l) Returns an array containing the names of all font families in this `GraphicsEnvironment` localized for the specified locale.
public Point	Returns: the point where Windows should be centered getCenterPoint() Returns the Point where Windows should be centered.
public abstract GraphicsDevice	Returns: the `GraphicsDevice` that represents the default screen device getDefaultScreenDevice() Returns the default screen `GraphicsDevice`.
pack-priv static String	getHeadlessMessage() Returns: warning message if headless state is assumed by default; null otherwise
private static boolean	getHeadlessProperty() Returns: the value of the property "java.awt.headless"
public static GraphicsEnvironment	Returns: the local `GraphicsEnvironment` getLocalGraphicsEnvironment() Returns the local `GraphicsEnvironment`.
public Rectangle	Returns: the maximum bounds for centered Windows getMaximumWindowBounds() Returns the maximum bounds for centered Windows.
public abstract GraphicsDevice[]	Returns: an array containing all the `GraphicsDevice` objects that represent screen devices getScreenDevices() Returns an array of all of the screen `GraphicsDevice` objects.
public static boolean	Returns: `true` if this environment cannot support a display, keyboard, and mouse; `false` otherwise isHeadless() Tests whether or not a display, keyboard, and mouse can be supported in this environment.
public boolean	Returns: `true` if a display, keyboard, and mouse can be supported in this environment; `false` otherwise isHeadlessInstance() Returns whether or not a display, keyboard, and mouse can be supported in this graphics environment.
public void	preferLocaleFonts() Indicates a preference for locale-specific fonts in the mapping of logical fonts to physical fonts.
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.
public boolean	Returns: true if the `font` is successfully registered in this `GraphicsEnvironment`. registerFont(Font the font to be registered font) Registers a created `Font` in this `GraphicsEnvironment`.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

defaultHeadless	back to summary
private static Boolean defaultHeadless The headless state assumed by default

headless	back to summary
private static Boolean headless The headless state of the Toolkit and GraphicsEnvironment

GraphicsEnvironment	back to summary
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

checkHeadless	back to summary
pack-priv static void checkHeadless() throws HeadlessException Check for headless state and throw HeadlessException if headless Since 1.4

checkHeadless

back to summary

pack-priv static void checkHeadless() throws HeadlessException

Check for headless state and throw HeadlessException if headless

Since: 1.4

createGraphics back to summary

createGraphics	back to summary
public abstract Graphics2D createGraphics(BufferedImage img) Returns a `Graphics2D` object for rendering into the specified `BufferedImage`. Parameters img:BufferedImage the specified `BufferedImage` Returns:Graphics2D a `Graphics2D` to be used for rendering into the specified `BufferedImage` Exceptions NullPointerException: if `img` is null

public abstract Graphics2D createGraphics(BufferedImage img)

Returns a Graphics2D object for rendering into the specified BufferedImage.

Parameters

img:BufferedImage: the specified BufferedImage

Returns:Graphics2D

a Graphics2D to be used for rendering into the specified BufferedImage

Exceptions

NullPointerException:: if img is null

getAllFonts back to summary

getAllFonts	back to summary
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 chosen 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:Font[] an array of `Font` objects Since 1.2 See Also `getAvailableFontFamilyNames`, `java.awt.Font`, `java.awt.Font#deriveFont`, `java.awt.Font#getFontName`

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 chosen 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:Font[]: an array of Font objects
Since: 1.2
See Also: getAvailableFontFamilyNames, java.awt.Font, java.awt.Font#deriveFont, java.awt.Font#getFontName

getAvailableFontFamilyNames back to summary

getAvailableFontFamilyNames	back to summary
public abstract String[] getAvailableFontFamilyNames() Returns an array containing the names of all font families in this `GraphicsEnvironment` localized for the default locale, as returned by `Locale.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:String[] an array of `String` containing 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 `getAllFonts`, `java.awt.Font`, `java.awt.Font#getFamily`

public abstract String[] getAvailableFontFamilyNames()

Returns an array containing the names of all font families in this GraphicsEnvironment localized for the default locale, as returned by Locale.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:String[]: an array of String containing 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: getAllFonts, java.awt.Font, java.awt.Font#getFamily

getAvailableFontFamilyNames back to summary

getAvailableFontFamilyNames	back to summary
public abstract String[] getAvailableFontFamilyNames(Locale l) Returns an array containing the names of all font families in this `GraphicsEnvironment` localized 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:Locale a `Locale` object that represents a particular geographical, political, or cultural region. Specifying `null` is equivalent to specifying `Locale.getDefault()`. Returns:String[] an array of `String` containing font family names localized for the specified `Locale`, or a suitable alternative name if no name exists for the specified locale. Since 1.2 See Also `getAllFonts`, `java.awt.Font`, `java.awt.Font#getFamily`

public abstract String[] getAvailableFontFamilyNames(Locale l)

Returns an array containing the names of all font families in this GraphicsEnvironment localized for the specified locale.

Parameters

l:Locale: a Locale object that represents a particular geographical, political, or cultural region. Specifying null is equivalent to specifying Locale.getDefault().

Returns:String[]

an array of String containing font family names localized for the specified Locale, or a suitable alternative name if no name exists for the specified locale.

Since

1.2

getCenterPoint back to summary

getCenterPoint	back to summary
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:Point the point where Windows should be centered Exceptions HeadlessException: if isHeadless() returns true Since 1.4 See Also `getMaximumWindowBounds`

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:Point

the point where Windows should be centered

Exceptions

HeadlessException:: if isHeadless() returns true

Since

1.4

See Also

getMaximumWindowBounds

getDefaultScreenDevice back to summary

getDefaultScreenDevice	back to summary
public abstract GraphicsDevice getDefaultScreenDevice() throws HeadlessException Returns the default screen `GraphicsDevice`. Returns:GraphicsDevice the `GraphicsDevice` that represents the default screen device Exceptions HeadlessException: if isHeadless() returns true See Also `isHeadless()`

public abstract GraphicsDevice getDefaultScreenDevice() throws HeadlessException

Returns the default screen GraphicsDevice.

Returns:GraphicsDevice

the GraphicsDevice that represents the default screen device

Exceptions

HeadlessException:: if isHeadless() returns true

See Also

isHeadless()

getHeadlessMessage	back to summary
pack-priv static String getHeadlessMessage() Returns:String warning message if headless state is assumed by default; null otherwise Since 1.5

getHeadlessProperty	back to summary
private static boolean getHeadlessProperty() Returns:boolean the value of the property "java.awt.headless" Since 1.4

getLocalGraphicsEnvironment back to summary

getLocalGraphicsEnvironment	back to summary
public static GraphicsEnvironment getLocalGraphicsEnvironment() Returns the local `GraphicsEnvironment`. Returns:GraphicsEnvironment the local `GraphicsEnvironment`

public static GraphicsEnvironment getLocalGraphicsEnvironment()

Returns the local GraphicsEnvironment.

Returns:GraphicsEnvironment: the local GraphicsEnvironment

getMaximumWindowBounds back to summary

getMaximumWindowBounds	back to summary
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:Rectangle the maximum bounds for centered Windows Exceptions HeadlessException: if isHeadless() returns true Since 1.4 See Also `getCenterPoint`, `GraphicsConfiguration#getBounds`, `Toolkit#getScreenInsets`

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:Rectangle

the maximum bounds for centered Windows

Exceptions

HeadlessException:: if isHeadless() returns true

Since

1.4

getScreenDevices back to summary

getScreenDevices	back to summary
public abstract GraphicsDevice[] getScreenDevices() throws HeadlessException Returns an array of all of the screen `GraphicsDevice` objects. Returns:GraphicsDevice[] an array containing all the `GraphicsDevice` objects that represent screen devices Exceptions HeadlessException: if isHeadless() returns true See Also `isHeadless()`

public abstract GraphicsDevice[] getScreenDevices() throws HeadlessException

Returns an array of all of the screen GraphicsDevice objects.

Returns:GraphicsDevice[]

an array containing all the GraphicsDevice objects that represent screen devices

Exceptions

HeadlessException:: if isHeadless() returns true

See Also

isHeadless()

isHeadless back to summary

isHeadless	back to summary
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:boolean `true` if this environment cannot support a display, keyboard, and mouse; `false` otherwise Since 1.4 See Also `java.awt.HeadlessException`

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

isHeadlessInstance back to summary

isHeadlessInstance	back to summary
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:boolean `true` if a display, keyboard, and mouse can be supported in this environment; `false` otherwise Since 1.4 See Also `java.awt.HeadlessException`, `isHeadless`

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:boolean: true if a display, keyboard, and mouse can be supported in this environment; false otherwise
Since: 1.4
See Also: java.awt.HeadlessException, isHeadless

preferLocaleFonts	back to summary
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

preferLocaleFonts

back to summary

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

preferProportionalFonts	back to summary
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

preferProportionalFonts

back to summary

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

registerFont back to summary

registerFont	back to summary
public boolean registerFont(Font font) Registers a created `Font` in this `GraphicsEnvironment`. A created font is one that was returned from calling `Font#createFont`, or derived from a created font by calling `Font#deriveFont`. After calling this method for such a font, it is available to be used in constructing new `Font`s by name or family name, and is enumerated by `getAvailableFontFamilyNames` and `getAllFonts` within the execution context of this application. Reasons that this method might not register the font and therefore return `false` are: The font is not a created `Font`. The font conflicts with a non-created `Font` already in this `GraphicsEnvironment`. For example if the name is that of a system font, or a logical font as described in the documentation of the `Font` class. 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:Font the font to be registered Returns:boolean true if the `font` is successfully registered in this `GraphicsEnvironment`. Exceptions NullPointerException: if `font` is null Since 1.6

public boolean registerFont(Font font)

Registers a created Font in this GraphicsEnvironment. A created font is one that was returned from calling Font#createFont, or derived from a created font by calling Font#deriveFont. After calling this method for such a font, it is available to be used in constructing new Fonts by name or family name, and is enumerated by getAvailableFontFamilyNames and getAllFonts within the execution context of this application.

Reasons that this method might not register the font and therefore return false are:

The font is not a created Font.
The font conflicts with a non-created Font already in this GraphicsEnvironment. For example if the name is that of a system font, or a logical font as described in the documentation of the Font class. 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:Font: the font to be registered

Returns:boolean

true if the font is successfully registered in this GraphicsEnvironment.

Exceptions

NullPointerException:: if font is null

Since

1.6

public abstract Class GraphicsEnvironment

Nested and Inner Type Summary

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Field Detail

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Method Detail

private final Class GraphicsEnvironment.LocalGE

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