FontRenderContextpublic 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 {@link java.awt.Graphics2D 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.
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| Fields Summary |
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| private transient AffineTransform | tx | | private transient Object | aaHintValue | | private transient Object | fmHintValue | | private transient boolean | defaulting |
| Constructors Summary |
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protected FontRenderContext()Constructs a new FontRenderContext
object.
aaHintValue = VALUE_TEXT_ANTIALIAS_DEFAULT;
fmHintValue = VALUE_FRACTIONALMETRICS_DEFAULT;
defaulting = true;
| public FontRenderContext(AffineTransform tx, boolean isAntiAliased, boolean usesFractionalMetrics)Constructs a FontRenderContext object from an
optional {@link 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 :
{@link #FontRenderContext(AffineTransform, Object, Object)}.
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;
}
| public FontRenderContext(AffineTransform tx, Object aaHint, Object fmHint)Constructs a FontRenderContext object from an
optional {@link AffineTransform} and two Object
values that determine if the newly constructed object has
anti-aliasing or fractional metrics.
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);
}
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| Methods Summary |
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| public boolean | equals(java.lang.Object obj)Return true if obj is an instance of FontRenderContext and has the same
transform, antialiasing, and fractional metrics values as this.
try {
return equals((FontRenderContext)obj);
}
catch (ClassCastException e) {
return false;
}
| | public boolean | equals(java.awt.font.FontRenderContext rhs)Return true if rhs has the same transform, antialiasing,
and fractional metrics values as this.
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());
}
| | public java.lang.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 {@link java.awt.RenderingHints java.awt.RenderingHints}.
if (defaulting) {
if (isAntiAliased()) {
return VALUE_TEXT_ANTIALIAS_ON;
} else {
return VALUE_TEXT_ANTIALIAS_OFF;
}
}
return aaHintValue;
| | public java.lang.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 {@link java.awt.RenderingHints java.awt.RenderingHints}.
if (defaulting) {
if (usesFractionalMetrics()) {
return VALUE_FRACTIONALMETRICS_ON;
} else {
return VALUE_FRACTIONALMETRICS_OFF;
}
}
return fmHintValue;
| | public java.awt.geom.AffineTransform | getTransform()Gets the transform that is used to scale typographical points
to pixels in this FontRenderContext.
return (tx == null) ? new AffineTransform() : new AffineTransform(tx);
| | public int | getTransformType()Returns the integer type of the affine transform for this
FontRenderContext as specified by
{@link java.awt.geom.AffineTransform#getType()}
if (!defaulting) {
if (tx == null) {
return AffineTransform.TYPE_IDENTITY;
} else {
return tx.getType();
}
} else {
return getTransform().getType();
}
| | public int | hashCode()Return a hashcode for this FontRenderContext.
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;
| | public boolean | isAntiAliased()Returns a boolean which indicates whether or not some form of
antialiasing is specified by this FontRenderContext.
Call {@link #getAntiAliasingHint() getAntiAliasingHint()}
for the specific rendering hint value.
return !(aaHintValue == VALUE_TEXT_ANTIALIAS_OFF ||
aaHintValue == VALUE_TEXT_ANTIALIAS_DEFAULT);
| | public boolean | isTransformed()Indicates whether or not this FontRenderContext object
measures text in a transformed render context.
if (!defaulting) {
return tx != null;
} else {
return !getTransform().isIdentity();
}
| | public boolean | usesFractionalMetrics()Returns a boolean which whether text fractional metrics mode
is used in this FontRenderContext.
Call {@link #getFractionalMetricsHint() getFractionalMetricsHint()}
to obtain the corresponding rendering hint value.
return !(fmHintValue == VALUE_FRACTIONALMETRICS_OFF ||
fmHintValue == VALUE_FRACTIONALMETRICS_DEFAULT);
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