java.awt.font
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

Field Summary

private boolean	bIsAntiAliased
private boolean	bUsesFractionalMetrics
private AffineTransform	tx

Constructor Summary

protected	FontRenderContext() Constructs a new FontRenderContext object.
	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.

Method Summary

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.
AffineTransform	getTransform() Gets the transform that is used to scale typographical points to pixels in this FontRenderContext.
int	hashCode() Return a hashcode for this FontRenderContext.
boolean	isAntiAliased() Gets the text anti-aliasing mode used in this FontRenderContext.
boolean	usesFractionalMetrics() Gets the text fractional metrics mode requested by the application for use in this FontRenderContext.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Field Detail

tx

private transient AffineTransform tx

bIsAntiAliased

private transient boolean bIsAntiAliased

bUsesFractionalMetrics

private transient boolean bUsesFractionalMetrics

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.

Parameters:

tx - the transform which is used to scale typographical points to pixels in this FontRenderContext. If null, an identity tranform is used.

isAntiAliased - determines if the newly contructed object has anti-aliasing

usesFractionalMetrics - determines if the newly constructed object uses fractional metrics

Method Detail

getTransform

public AffineTransform getTransform()

Gets the transform that is used to scale typographical points to pixels in this FontRenderContext.

Returns:

the AffineTransform of this FontRenderContext.

See Also:

AffineTransform

isAntiAliased

public boolean isAntiAliased()

Gets the text anti-aliasing mode used in this FontRenderContext.

Returns:

true, if text is anti-aliased in this FontRenderContext; false otherwise.

See Also:

RenderingHints.KEY_TEXT_ANTIALIASING

usesFractionalMetrics

public boolean usesFractionalMetrics()

Gets the text fractional metrics mode requested by the application for use in this FontRenderContext.

Returns:

true, if layout should be performed with fractional metrics; false otherwise. in this FontRenderContext.

See Also:

RenderingHints.KEY_FRACTIONALMETRICS

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 class Object

Parameters:

obj - the object to test for equality

Returns:

true if the specified object is equal to this FontRenderContext; false otherwise.

See Also:

Object.hashCode(), Hashtable

equals

public boolean equals(FontRenderContext rhs)

Return true if rhs has the same transform, antialiasing, and fractional metrics values as this.

Parameters:

rhs - the FontRenderContext to test for equality

Returns:

true if rhs is equal to this FontRenderContext; false otherwise.

hashCode

public int hashCode()

Return a hashcode for this FontRenderContext.

Overrides:

hashCode in class Object

Returns:

a hash code value for this object.

See Also:

Object.equals(java.lang.Object), Hashtable