Class FontRenderContext
- java.lang.Object
-
- java.awt.font.FontRenderContext
public class FontRenderContext extends Object
The FontRenderContext
class is a container for the information needed to correctly measure text. The measurement of text can vary because of rules that map outlines to pixels, and rendering hints provided by an application.
One such piece of information is a transform that scales typographical points to pixels. (A point is defined to be exactly 1/72 of an inch, which is slightly different than the traditional mechanical measurement of a point.) A character that is rendered at 12pt on a 600dpi device might have a different size than the same character rendered at 12pt on a 72dpi device because of such factors as rounding to pixel boundaries and hints that the font designer may have specified.
Anti-aliasing and Fractional-metrics specified by an application can also affect the size of a character because of rounding to pixel boundaries.
Typically, instances of FontRenderContext
are obtained from a Graphics2D
object. A FontRenderContext
which is directly constructed will most likely not represent any actual graphics device, and may lead to unexpected or incorrect results.
- See Also:
-
RenderingHints.KEY_TEXT_ANTIALIASING
,RenderingHints.KEY_FRACTIONALMETRICS
,Graphics2D.getFontRenderContext()
,LineMetrics
Constructor Summary
Modifier | Constructor | Description |
---|---|---|
protected | FontRenderContext() | Constructs a new |
FontRenderContext(AffineTransform tx,
boolean isAntiAliased,
boolean usesFractionalMetrics) | Constructs a | |
FontRenderContext(AffineTransform tx,
Object aaHint,
Object fmHint) | Constructs a |
Method Summary
Modifier and Type | Method | Description |
---|---|---|
boolean | equals(FontRenderContext rhs) | Return true if rhs has the same transform, antialiasing, and fractional metrics values as this. |
boolean | equals(Object obj) | Return true if obj is an instance of FontRenderContext and has the same transform, antialiasing, and fractional metrics values as this. |
Object | getAntiAliasingHint() | Return the text anti-aliasing rendering mode hint used in this |
Object | getFractionalMetricsHint() | Return the text fractional metrics rendering mode hint used in this |
AffineTransform | getTransform() | Gets the transform that is used to scale typographical points to pixels in this |
int | getTransformType() | Returns the integer type of the affine transform for this |
int | hashCode() | Return a hashcode for this FontRenderContext. |
boolean | isAntiAliased() | Returns a boolean which indicates whether or not some form of antialiasing is specified by this |
boolean | isTransformed() | Indicates whether or not this |
boolean | usesFractionalMetrics() | Returns a boolean which whether text fractional metrics mode is used in this |
Methods declared in class java.lang.Object
clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait
Constructor Detail
FontRenderContext
protected FontRenderContext()
Constructs a new FontRenderContext
object.
FontRenderContext
public FontRenderContext(AffineTransform tx, boolean isAntiAliased, boolean usesFractionalMetrics)
Constructs a FontRenderContext
object from an optional AffineTransform
and two boolean
values that determine if the newly constructed object has anti-aliasing or fractional metrics. In each case the boolean values true
and false
correspond to the rendering hint values ON
and OFF
respectively.
To specify other hint values, use the constructor which specifies the rendering hint values as parameters : FontRenderContext(AffineTransform, Object, Object)
.
- Parameters:
-
tx
- the transform which is used to scale typographical points to pixels in thisFontRenderContext
. If null, an identity transform is used. -
isAntiAliased
- determines if the newly constructed object has anti-aliasing. -
usesFractionalMetrics
- determines if the newly constructed object has fractional metrics.
FontRenderContext
public FontRenderContext(AffineTransform tx, Object aaHint, Object fmHint)
Constructs a FontRenderContext
object from an optional AffineTransform
and two Object
values that determine if the newly constructed object has anti-aliasing or fractional metrics.
- Parameters:
-
tx
- the transform which is used to scale typographical points to pixels in thisFontRenderContext
. If null, an identity transform is used. -
aaHint
- - one of the text antialiasing rendering hint values defined injava.awt.RenderingHints
. Any other value will throwIllegalArgumentException
.VALUE_TEXT_ANTIALIAS_DEFAULT
may be specified, in which case the mode used is implementation dependent. -
fmHint
- - one of the text fractional rendering hint values defined injava.awt.RenderingHints
.VALUE_FRACTIONALMETRICS_DEFAULT
may be specified, in which case the mode used is implementation dependent. Any other value will throwIllegalArgumentException
- Throws:
-
IllegalArgumentException
- if the hints are not one of the legal values. - Since:
- 1.6
Method Detail
isTransformed
public boolean isTransformed()
Indicates whether or not this FontRenderContext
object measures text in a transformed render context.
- Returns:
-
true
if thisFontRenderContext
object has a non-identity AffineTransform attribute.false
otherwise. - Since:
- 1.6
- See Also:
getTransform()
getTransformType
public int getTransformType()
Returns the integer type of the affine transform for this FontRenderContext
as specified by AffineTransform.getType()
- Returns:
- the type of the transform.
- Since:
- 1.6
- See Also:
AffineTransform
getTransform
public AffineTransform getTransform()
Gets the transform that is used to scale typographical points to pixels in this FontRenderContext
.
- Returns:
- the
AffineTransform
of thisFontRenderContext
. - See Also:
AffineTransform
isAntiAliased
public boolean isAntiAliased()
Returns a boolean which indicates whether or not some form of antialiasing is specified by this FontRenderContext
. Call getAntiAliasingHint()
for the specific rendering hint value.
- Returns:
-
true
, if text is anti-aliased in thisFontRenderContext
;false
otherwise. - See Also:
-
RenderingHints.KEY_TEXT_ANTIALIASING
,FontRenderContext(AffineTransform,boolean,boolean)
,FontRenderContext(AffineTransform,Object,Object)
usesFractionalMetrics
public boolean usesFractionalMetrics()
Returns a boolean which whether text fractional metrics mode is used in this FontRenderContext
. Call getFractionalMetricsHint()
to obtain the corresponding rendering hint value.
- Returns:
-
true
, if layout should be performed with fractional metrics;false
otherwise. in thisFontRenderContext
. - See Also:
-
RenderingHints.KEY_FRACTIONALMETRICS
,FontRenderContext(AffineTransform,boolean,boolean)
,FontRenderContext(AffineTransform,Object,Object)
getAntiAliasingHint
public Object getAntiAliasingHint()
Return the text anti-aliasing rendering mode hint used in this FontRenderContext
. This will be one of the text antialiasing rendering hint values defined in java.awt.RenderingHints
.
- Returns:
- text anti-aliasing rendering mode hint used in this
FontRenderContext
. - Since:
- 1.6
getFractionalMetricsHint
public Object getFractionalMetricsHint()
Return the text fractional metrics rendering mode hint used in this FontRenderContext
. This will be one of the text fractional metrics rendering hint values defined in java.awt.RenderingHints
.
- Returns:
- the text fractional metrics rendering mode hint used in this
FontRenderContext
. - Since:
- 1.6
equals
public boolean equals(Object obj)
Return true if obj is an instance of FontRenderContext and has the same transform, antialiasing, and fractional metrics values as this.
- Overrides:
-
equals
in classObject
- Parameters:
-
obj
- the object to test for equality - Returns:
-
true
if the specified object is equal to thisFontRenderContext
;false
otherwise. - See Also:
-
Object.hashCode()
,HashMap
equals
public boolean equals(FontRenderContext rhs)
Return true if rhs has the same transform, antialiasing, and fractional metrics values as this.
- Parameters:
-
rhs
- theFontRenderContext
to test for equality - Returns:
-
true
ifrhs
is equal to thisFontRenderContext
;false
otherwise. - Since:
- 1.4
hashCode
public int hashCode()
Return a hashcode for this FontRenderContext.
- Overrides:
-
hashCode
in classObject
- Returns:
- a hash code value for this object.
- See Also:
-
Object.equals(java.lang.Object)
,System.identityHashCode(java.lang.Object)