/*
* Copyright (c) 1998, 2013, Oracle and/or its affiliates. All rights reserved.
* ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*
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/*
* @author Charlton Innovations, Inc.
*/
package java.awt.font;
import java.awt.
RenderingHints;
import static java.awt.
RenderingHints.*;
import java.awt.geom.
AffineTransform;
/**
* The <code>FontRenderContext</code> 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.
* <p>
* 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.
* <p>
* Anti-aliasing and Fractional-metrics specified by an application can also
* affect the size of a character because of rounding to pixel
* boundaries.
* <p>
* Typically, instances of <code>FontRenderContext</code> are
* obtained from a {@link java.awt.Graphics2D Graphics2D} object. A
* <code>FontRenderContext</code> which is directly constructed will
* most likely not represent any actual graphics device, and may lead
* to unexpected or incorrect results.
* @see java.awt.RenderingHints#KEY_TEXT_ANTIALIASING
* @see java.awt.RenderingHints#KEY_FRACTIONALMETRICS
* @see java.awt.Graphics2D#getFontRenderContext()
* @see java.awt.font.LineMetrics
*/
public class
FontRenderContext {
private transient
AffineTransform tx;
private transient
Object aaHintValue;
private transient
Object fmHintValue;
private transient boolean
defaulting;
/**
* Constructs a new <code>FontRenderContext</code>
* object.
*
*/
protected
FontRenderContext() {
aaHintValue =
VALUE_TEXT_ANTIALIAS_DEFAULT;
fmHintValue =
VALUE_FRACTIONALMETRICS_DEFAULT;
defaulting = true;
}
/**
* Constructs a <code>FontRenderContext</code> object from an
* optional {@link AffineTransform} and two <code>boolean</code>
* values that determine if the newly constructed object has
* anti-aliasing or fractional metrics.
* In each case the boolean values <CODE>true</CODE> and <CODE>false</CODE>
* correspond to the rendering hint values <CODE>ON</CODE> and
* <CODE>OFF</CODE> respectively.
* <p>
* To specify other hint values, use the constructor which
* specifies the rendering hint values as parameters :
* {@link #FontRenderContext(AffineTransform, Object, Object)}.
* @param tx the transform which is used to scale typographical points
* to pixels in this <code>FontRenderContext</code>. If null, an
* identity transform is used.
* @param isAntiAliased determines if the newly constructed object
* has anti-aliasing.
* @param usesFractionalMetrics determines if the newly constructed
* object has fractional metrics.
*/
public
FontRenderContext(
AffineTransform tx,
boolean
isAntiAliased,
boolean
usesFractionalMetrics) {
if (
tx != null && !
tx.
isIdentity()) {
this.
tx = new
AffineTransform(
tx);
}
if (
isAntiAliased) {
aaHintValue =
VALUE_TEXT_ANTIALIAS_ON;
} else {
aaHintValue =
VALUE_TEXT_ANTIALIAS_OFF;
}
if (
usesFractionalMetrics) {
fmHintValue =
VALUE_FRACTIONALMETRICS_ON;
} else {
fmHintValue =
VALUE_FRACTIONALMETRICS_OFF;
}
}
/**
* Constructs a <code>FontRenderContext</code> object from an
* optional {@link AffineTransform} and two <code>Object</code>
* values that determine if the newly constructed object has
* anti-aliasing or fractional metrics.
* @param tx the transform which is used to scale typographical points
* to pixels in this <code>FontRenderContext</code>. If null, an
* identity transform is used.
* @param aaHint - one of the text antialiasing rendering hint values
* defined in {@link java.awt.RenderingHints java.awt.RenderingHints}.
* Any other value will throw <code>IllegalArgumentException</code>.
* {@link java.awt.RenderingHints#VALUE_TEXT_ANTIALIAS_DEFAULT VALUE_TEXT_ANTIALIAS_DEFAULT}
* may be specified, in which case the mode used is implementation
* dependent.
* @param fmHint - one of the text fractional rendering hint values defined
* in {@link java.awt.RenderingHints java.awt.RenderingHints}.
* {@link java.awt.RenderingHints#VALUE_FRACTIONALMETRICS_DEFAULT VALUE_FRACTIONALMETRICS_DEFAULT}
* may be specified, in which case the mode used is implementation
* dependent.
* Any other value will throw <code>IllegalArgumentException</code>
* @throws IllegalArgumentException if the hints are not one of the
* legal values.
* @since 1.6
*/
public
FontRenderContext(
AffineTransform tx,
Object aaHint,
Object fmHint){
if (
tx != null && !
tx.
isIdentity()) {
this.
tx = new
AffineTransform(
tx);
}
try {
if (
KEY_TEXT_ANTIALIASING.
isCompatibleValue(
aaHint)) {
aaHintValue =
aaHint;
} else {
throw new
IllegalArgumentException("AA hint:" +
aaHint);
}
} catch (
Exception e) {
throw new
IllegalArgumentException("AA hint:" +
aaHint);
}
try {
if (
KEY_FRACTIONALMETRICS.
isCompatibleValue(
fmHint)) {
fmHintValue =
fmHint;
} else {
throw new
IllegalArgumentException("FM hint:" +
fmHint);
}
} catch (
Exception e) {
throw new
IllegalArgumentException("FM hint:" +
fmHint);
}
}
/**
* Indicates whether or not this <code>FontRenderContext</code> object
* measures text in a transformed render context.
* @return <code>true</code> if this <code>FontRenderContext</code>
* object has a non-identity AffineTransform attribute.
* <code>false</code> otherwise.
* @see java.awt.font.FontRenderContext#getTransform
* @since 1.6
*/
public boolean
isTransformed() {
if (!
defaulting) {
return
tx != null;
} else {
return !
getTransform().
isIdentity();
}
}
/**
* Returns the integer type of the affine transform for this
* <code>FontRenderContext</code> as specified by
* {@link java.awt.geom.AffineTransform#getType()}
* @return the type of the transform.
* @see AffineTransform
* @since 1.6
*/
public int
getTransformType() {
if (!
defaulting) {
if (
tx == null) {
return
AffineTransform.
TYPE_IDENTITY;
} else {
return
tx.
getType();
}
} else {
return
getTransform().
getType();
}
}
/**
* Gets the transform that is used to scale typographical points
* to pixels in this <code>FontRenderContext</code>.
* @return the <code>AffineTransform</code> of this
* <code>FontRenderContext</code>.
* @see AffineTransform
*/
public
AffineTransform getTransform() {
return (
tx == null) ? new
AffineTransform() : new
AffineTransform(
tx);
}
/**
* Returns a boolean which indicates whether or not some form of
* antialiasing is specified by this <code>FontRenderContext</code>.
* Call {@link #getAntiAliasingHint() getAntiAliasingHint()}
* for the specific rendering hint value.
* @return <code>true</code>, if text is anti-aliased in this
* <code>FontRenderContext</code>; <code>false</code> otherwise.
* @see java.awt.RenderingHints#KEY_TEXT_ANTIALIASING
* @see #FontRenderContext(AffineTransform,boolean,boolean)
* @see #FontRenderContext(AffineTransform,Object,Object)
*/
public boolean
isAntiAliased() {
return !(
aaHintValue ==
VALUE_TEXT_ANTIALIAS_OFF ||
aaHintValue ==
VALUE_TEXT_ANTIALIAS_DEFAULT);
}
/**
* Returns a boolean which whether text fractional metrics mode
* is used in this <code>FontRenderContext</code>.
* Call {@link #getFractionalMetricsHint() getFractionalMetricsHint()}
* to obtain the corresponding rendering hint value.
* @return <code>true</code>, if layout should be performed with
* fractional metrics; <code>false</code> otherwise.
* in this <code>FontRenderContext</code>.
* @see java.awt.RenderingHints#KEY_FRACTIONALMETRICS
* @see #FontRenderContext(AffineTransform,boolean,boolean)
* @see #FontRenderContext(AffineTransform,Object,Object)
*/
public boolean
usesFractionalMetrics() {
return !(
fmHintValue ==
VALUE_FRACTIONALMETRICS_OFF ||
fmHintValue ==
VALUE_FRACTIONALMETRICS_DEFAULT);
}
/**
* Return the text anti-aliasing rendering mode hint used in this
* <code>FontRenderContext</code>.
* This will be one of the text antialiasing rendering hint values
* defined in {@link java.awt.RenderingHints java.awt.RenderingHints}.
* @return text anti-aliasing rendering mode hint used in this
* <code>FontRenderContext</code>.
* @since 1.6
*/
public
Object getAntiAliasingHint() {
if (
defaulting) {
if (
isAntiAliased()) {
return
VALUE_TEXT_ANTIALIAS_ON;
} else {
return
VALUE_TEXT_ANTIALIAS_OFF;
}
}
return
aaHintValue;
}
/**
* Return the text fractional metrics rendering mode hint used in this
* <code>FontRenderContext</code>.
* This will be one of the text fractional metrics rendering hint values
* defined in {@link java.awt.RenderingHints java.awt.RenderingHints}.
* @return the text fractional metrics rendering mode hint used in this
* <code>FontRenderContext</code>.
* @since 1.6
*/
public
Object getFractionalMetricsHint() {
if (
defaulting) {
if (
usesFractionalMetrics()) {
return
VALUE_FRACTIONALMETRICS_ON;
} else {
return
VALUE_FRACTIONALMETRICS_OFF;
}
}
return
fmHintValue;
}
/**
* Return true if obj is an instance of FontRenderContext and has the same
* transform, antialiasing, and fractional metrics values as this.
* @param obj the object to test for equality
* @return <code>true</code> if the specified object is equal to
* this <code>FontRenderContext</code>; <code>false</code>
* otherwise.
*/
public boolean
equals(
Object obj) {
try {
return
equals((
FontRenderContext)
obj);
}
catch (
ClassCastException e) {
return false;
}
}
/**
* Return true if rhs has the same transform, antialiasing,
* and fractional metrics values as this.
* @param rhs the <code>FontRenderContext</code> to test for equality
* @return <code>true</code> if <code>rhs</code> is equal to
* this <code>FontRenderContext</code>; <code>false</code>
* otherwise.
* @since 1.4
*/
public boolean
equals(
FontRenderContext rhs) {
if (this ==
rhs) {
return true;
}
if (
rhs == null) {
return false;
}
/* if neither instance is a subclass, reference values directly. */
if (!
rhs.
defaulting && !
defaulting) {
if (
rhs.
aaHintValue ==
aaHintValue &&
rhs.
fmHintValue ==
fmHintValue) {
return
tx == null ?
rhs.
tx == null :
tx.
equals(
rhs.
tx);
}
return false;
} else {
return
rhs.
getAntiAliasingHint() ==
getAntiAliasingHint() &&
rhs.
getFractionalMetricsHint() ==
getFractionalMetricsHint() &&
rhs.
getTransform().
equals(
getTransform());
}
}
/**
* Return a hashcode for this FontRenderContext.
*/
public int
hashCode() {
int
hash =
tx == null ? 0 :
tx.
hashCode();
/* SunHints value objects have identity hashcode, so we can rely on
* this to ensure that two equal FRC's have the same hashcode.
*/
if (
defaulting) {
hash +=
getAntiAliasingHint().
hashCode();
hash +=
getFractionalMetricsHint().
hashCode();
} else {
hash +=
aaHintValue.
hashCode();
hash +=
fmHintValue.
hashCode();
}
return
hash;
}
}