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.GraphicsDevice
,
GraphicsConfiguration
Modifier | Constructor and Description |
---|---|
protected |
GraphicsEnvironment()
This is an abstract class and cannot be instantiated directly.
|
Modifier and Type | Method and Description |
---|---|
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 in this
GraphicsEnvironment localized for the default locale,
as returned by Locale.getDefault() . |
abstract String[] |
getAvailableFontFamilyNames(Locale l)
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 (e.g.
|
boolean |
registerFont(Font font)
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
otherwiseHeadlessException
public 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
otherwiseHeadlessException
,
isHeadless()
public abstract GraphicsDevice[] getScreenDevices() throws HeadlessException
GraphicsDevice
objects.GraphicsDevice
objects that represent screen devicesHeadlessException
- if isHeadless() returns trueisHeadless()
public abstract GraphicsDevice getDefaultScreenDevice() throws HeadlessException
GraphicsDevice
.GraphicsDevice
that represents the
default screen deviceHeadlessException
- if isHeadless() returns trueisHeadless()
public 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
objectsgetAvailableFontFamilyNames()
,
Font
,
Font.deriveFont(int, float)
,
Font.getFontName()
public 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.getAllFonts()
,
Font
,
Font.getFamily()
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.getAllFonts()
,
Font
,
Font.getFamily()
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
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 truegetMaximumWindowBounds()
public Rectangle getMaximumWindowBounds() throws HeadlessException
To get the usable bounds of a single display, use
GraphicsConfiguration.getBounds()
and
Toolkit.getScreenInsets()
.
HeadlessException
- if isHeadless() returns truegetCenterPoint()
,
GraphicsConfiguration.getBounds()
,
Toolkit.getScreenInsets(java.awt.GraphicsConfiguration)
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