public abstract class GraphicsEnvironment extends Object
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.Modifier | Constructor | Description |
---|---|---|
protected |
This is an abstract class and cannot be instantiated directly. |
Modifier and Type | Method | Description |
---|---|---|
abstract Graphics2D |
createGraphics |
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 in this GraphicsEnvironment localized for the default locale, as returned by Locale.getDefault() . |
abstract String[] |
getAvailableFontFamilyNames |
Returns an array containing the names of all font families in this GraphicsEnvironment localized for the specified locale. |
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. |
void |
preferLocaleFonts() |
Indicates a preference for locale-specific fonts in the mapping of logical fonts to physical fonts. |
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. |
boolean |
registerFont |
Registers a created Font in this GraphicsEnvironment . |
protected GraphicsEnvironment()
public static GraphicsEnvironment getLocalGraphicsEnvironment()
GraphicsEnvironment
.GraphicsEnvironment
public static boolean isHeadless()
true
if this environment cannot support a display, keyboard, and mouse; false
otherwisepublic boolean isHeadlessInstance()
HeadlessException
will be thrown from areas of the graphics environment that are dependent on a display, keyboard, or mouse.true
if a display, keyboard, and mouse can be supported in this environment; false
otherwisepublic abstract GraphicsDevice[] getScreenDevices() throws HeadlessException
GraphicsDevice
objects.GraphicsDevice
objects that represent screen devicesHeadlessException
- if isHeadless() returns truepublic abstract GraphicsDevice getDefaultScreenDevice() throws HeadlessException
GraphicsDevice
.GraphicsDevice
that represents the default screen deviceHeadlessException
- if isHeadless() returns truepublic abstract Graphics2D createGraphics(BufferedImage img)
Graphics2D
object for rendering into the specified BufferedImage
.img
- the specified BufferedImage
Graphics2D
to be used for rendering into the specified BufferedImage
NullPointerException
- if img
is nullpublic abstract Font[] getAllFonts()
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.
Font
objectspublic abstract String[] getAvailableFontFamilyNames()
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.
String
containing font family names localized for the default locale, or a suitable alternative name if no name exists for this locale.public abstract String[] getAvailableFontFamilyNames(Locale l)
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.
l
- a Locale
object that represents a particular geographical, political, or cultural region. Specifying null
is equivalent to specifying Locale.getDefault()
.String
containing font family names localized for the specified Locale
, or a suitable alternative name if no name exists for the specified locale.public boolean registerFont(Font font)
Font
in this GraphicsEnvironment
. A created font is one that was returned from calling Font.createFont(int, java.io.InputStream)
, or derived from a created font by calling Font.deriveFont(int, float)
. 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 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 false
are:
Font
. 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.
font
- the font to be registeredfont
is successfully registered in this GraphicsEnvironment
.NullPointerException
- if font
is nullpublic void preferLocaleFonts()
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.
public void preferProportionalFonts()
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.
public Point getCenterPoint() throws HeadlessException
HeadlessException
- if isHeadless() returns truepublic Rectangle getMaximumWindowBounds() throws HeadlessException
To get the usable bounds of a single display, use GraphicsConfiguration.getBounds()
and Toolkit.getScreenInsets()
.
HeadlessException
- if isHeadless() returns true
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https://docs.oracle.com/en/java/javase/21/docs/api/java.desktop/java/awt/GraphicsEnvironment.html