The Java Tutorials have been written for JDK 8. Examples and practices described in this page don't take advantage of improvements introduced in later releases and might use technology no longer available.
See Java Language Changes for a summary of updated language features in Java SE 9 and subsequent releases.
See JDK Release Notes for information about new features, enhancements, and removed or deprecated options for all JDK releases.
By default, when text contains numeric values, those values are displayed using Latin (European) digits. When other Unicode digit shapes are preferred, use the
java.awt.font.NumericShaper
class. The NumericShaper
API enables you to display a numeric value represented internally as an ASCII value in any Unicode digit shape.
The following code snippet, from the
ArabicDigits
example, shows how to use a NumericShaper
instance to convert Latin digits to Arabic digits. The line that determines the shaping action is bolded.
ArabicDigitsPanel(String fontname) { HashMap map = new HashMap(); Font font = new Font(fontname, Font.PLAIN, 60); map.put(TextAttribute.FONT, font); map.put(TextAttribute.NUMERIC_SHAPING, NumericShaper.getShaper(NumericShaper.ARABIC)); FontRenderContext frc = new FontRenderContext(null, false, false); layout = new TextLayout(text, map, frc); } // ... public void paint(Graphics g) { Graphics2D g2d = (Graphics2D)g; layout.draw(g2d, 10, 50); }
The NumericShaper
instance for Arabic digits is fetched and placed into a HashMap
for the
TextLayout.NUMERIC_SHAPING
attribute key. The hash map is passed to the TextLayout
instance. After rendering the text in the paint
method, the digits are displayed in the desired script. In this example, the Latin digits, 0 through 9, are drawn as Arabic digits.
The previous example uses the NumericShaper.ARABIC
constant to retrieve the desired shaper, but the
NumericShaper
class provides constants for many languages. These constants are defined as bit masks and are referred to as the NumericShaper
bit mask-based constants.
An alternative way to specify a particular set of digits is to use the
NumericShaper.Range
enumerated type (enum). This enum, introduced in the Java SE 7 release, also provides a set of
constants. Although these constants are defined using different mechanisms, the NumericShaper.ARABIC
bit mask is functionally equivalent to the NumericShaper.Range.ARABIC
enum, and there is a corresponding getShaper
method for each constant type:
The
ArabicDigitsEnum
example is identical to the ArabicDigits example, except it uses the NumericShaper.Range
enum to specify the language script:
ArabicDigitsEnumPanel(String fontname) { HashMap map = new HashMap(); Font font = new Font(fontname, Font.PLAIN, 60); map.put(TextAttribute.FONT, font); map.put(TextAttribute.NUMERIC_SHAPING, NumericShaper.getShaper(NumericShaper.Range.ARABIC)); FontRenderContext frc = new FontRenderContext(null, false, false); layout = new TextLayout(text, map, frc); }
Both getShaper
methods accept a singleRange
parameter. With either constant type, you can specify a range of script-specific digits. The bit mask-based constants can be combined using the OR
operand, or you can create a set of NumericShaper.Range
enums. The following shows how to define a range using each constant type:
NumericShaper.MONGOLIAN | NumericShaper.THAI | NumericShaper.TIBETAN EnumSet.of( NumericShaper.Range.MONGOLIAN, NumericShaper.Range.THAI, NumericShaper.Range.TIBETAN)
You can query the NumericShaper
object to determine which ranges it supports using either the
getRanges
method for bit mask-based shapers or the
getRangeSet
method for enum-based shapers.
You can use either the traditional bit masked-based constants or the Range
enum-based constants. Here are some considerations when deciding which to use:
Range
API requires JDK 7 or later.Range
API covers more Unicode ranges than the bit-masked API.Range
API.The
ArabicDigits
example was designed to use the shaper for a specific language, but sometimes the digits must be rendered according to the language context. For example, if the text that precedes the digits uses the Thai script, Thai digits are preferred. If the text is displayed in Tibetan, Tibetan digits are preferred.
You can accomplish this using one of the getContextualShaper
methods:
The first two methods use the bit-mask constants, and the last two use the enum constants. The methods that accept a defaultContext
parameter enable you to specify the initial shaper that is used when numeric values are displayed before text. When no default context is defined, any leading digits are displayed using Latin shapes.
The
ShapedDigits
example shows how shapers work. Five text layouts are displayed:
ALL_RANGES
bit mask, but the shaper does not specify a default context.The following lines of code show how the shapers, if used, are defined:
NumericShaper arabic = NumericShaper.getShaper(NumericShaper.ARABIC);
NumericShaper contextualArabic = NumericShaper.getContextualShaper(NumericShaper.ARABIC, NumericShaper.ARABIC);
NumericShaper contextualArabicASCII = NumericShaper.getContextualShaper(NumericShaper.ARABIC);
NumericShaper contextualAll = NumericShaper.getContextualShaper(NumericShaper.ALL_RANGES);
See the
ShapedDigits.java
example for further implementation details.