Module java.desktop
Package java.awt.font

Class TextAttribute

java.lang.Object
java.text.AttributedCharacterIterator.Attribute
java.awt.font.TextAttribute
All Implemented Interfaces:
Serializable
public final class TextAttribute extends AttributedCharacterIterator.Attribute
The TextAttribute class defines attribute keys and attribute values used for text rendering.

TextAttribute instances are used as attribute keys to identify attributes in Font, TextLayout, AttributedCharacterIterator, and other classes handling text attributes. Other constants defined in this class can be used as attribute values.

For each text attribute, the documentation provides:

  • the type of its value,
  • the relevant predefined constants, if any
  • the default effect if the attribute is absent
  • the valid values if there are limitations
  • a description of the effect.

Values

  • The values of attributes must always be immutable.
  • Where value limitations are given, any value outside of that set is reserved for future use; the value will be treated as the default.
  • The value null is treated the same as the default value and results in the default behavior.
  • If the value is not of the proper type, the attribute will be ignored.
  • The identity of the value does not matter, only the actual value. For example, TextAttribute.WEIGHT_BOLD and Float.valueOf(2.0f) indicate the same WEIGHT.
  • Attribute values of type Number (used for WEIGHT, WIDTH, POSTURE, SIZE, JUSTIFICATION, and TRACKING) can vary along their natural range and are not restricted to the predefined constants. Number.floatValue() is used to get the actual value from the Number.
  • The values for WEIGHT, WIDTH, and POSTURE are interpolated by the system, which can select the 'nearest available' font or use other techniques to approximate the user's request.

Summary of attributes

Key, value type, principal constants, and default value behavior of all TextAttributes
Key Value Type Principal Constants Default Value
FAMILY String See Font DIALOG, DIALOG_INPUT,
SERIF, SANS_SERIF, and MONOSPACED. 		"Default" (use platform default)
WEIGHT Number WEIGHT_REGULAR, WEIGHT_BOLD WEIGHT_REGULAR
WIDTH Number WIDTH_CONDENSED, WIDTH_REGULAR,
WIDTH_EXTENDED 		WIDTH_REGULAR
POSTURE Number POSTURE_REGULAR, POSTURE_OBLIQUE POSTURE_REGULAR
SIZE Number none 12.0
TRANSFORM TransformAttribute See TransformAttribute IDENTITY TransformAttribute.IDENTITY
SUPERSCRIPT Integer SUPERSCRIPT_SUPER, SUPERSCRIPT_SUB 0 (use the standard glyphs and metrics)
FONT Font none null (do not override font resolution)
CHAR_REPLACEMENT GraphicAttribute none null (draw text using font glyphs)
FOREGROUND Paint none null (use current graphics paint)
BACKGROUND Paint none null (do not render background)
UNDERLINE Integer UNDERLINE_ON -1 (do not render underline)
STRIKETHROUGH Boolean STRIKETHROUGH_ON false (do not render strikethrough)
RUN_DIRECTION Boolean RUN_DIRECTION_LTR
RUN_DIRECTION_RTL 		null (use Bidi standard default)
BIDI_EMBEDDING Integer none 0 (use base line direction)
JUSTIFICATION Number JUSTIFICATION_FULL JUSTIFICATION_FULL
INPUT_METHOD_HIGHLIGHT InputMethodHighlight,
Annotation 		(see class) null (do not apply input highlighting)
INPUT_METHOD_UNDERLINE Integer UNDERLINE_LOW_ONE_PIXEL,
UNDERLINE_LOW_TWO_PIXEL 		-1 (do not render underline)
SWAP_COLORS Boolean SWAP_COLORS_ON false (do not swap colors)
NUMERIC_SHAPING NumericShaper none null (do not shape digits)
KERNING Integer KERNING_ON 0 (do not request kerning)
LIGATURES Integer LIGATURES_ON 0 (do not form optional ligatures)
TRACKING Number TRACKING_LOOSE, TRACKING_TIGHT 0 (do not add tracking)
See Also:

  • Field Details

    • FAMILY

      public static final TextAttribute FAMILY
      Attribute key for the font name. Values are instances of String. The default value is "Default", which causes the platform default font family to be used.

      The Font class defines constants for the logical font names DIALOG, DIALOG_INPUT, SANS_SERIF, SERIF, and MONOSPACED.

      This defines the value passed as name to the Font constructor. Both logical and physical font names are allowed. If a font with the requested name is not found, the default font is used.

      Note: This attribute is unfortunately misnamed, as it specifies the face name and not just the family. Thus values such as "Lucida Sans Bold" will select that face if it exists. Note, though, that if the requested face does not exist, the default will be used with regular weight. The "Bold" in the name is part of the face name, not a separate request that the font's weight be bold.

    • WEIGHT

      public static final TextAttribute WEIGHT
      Attribute key for the weight of a font. Values are instances of Number. The default value is WEIGHT_REGULAR.

      Several constant values are provided, see WEIGHT_EXTRA_LIGHT, WEIGHT_LIGHT, WEIGHT_DEMILIGHT, WEIGHT_REGULAR, WEIGHT_SEMIBOLD, WEIGHT_MEDIUM, WEIGHT_DEMIBOLD, WEIGHT_BOLD, WEIGHT_HEAVY, WEIGHT_EXTRABOLD, and WEIGHT_ULTRABOLD. The value WEIGHT_BOLD corresponds to the style value Font.BOLD as passed to the Font constructor.

      The value is roughly the ratio of the stem width to that of the regular weight.

      The system can interpolate the provided value.

    • WEIGHT_EXTRA_LIGHT

      public static final Float WEIGHT_EXTRA_LIGHT
      The lightest predefined weight.
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    • WEIGHT_LIGHT

      public static final Float WEIGHT_LIGHT
      The standard light weight.
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    • WEIGHT_DEMILIGHT

      public static final Float WEIGHT_DEMILIGHT
      An intermediate weight between WEIGHT_LIGHT and WEIGHT_STANDARD.
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    • WEIGHT_REGULAR

      public static final Float WEIGHT_REGULAR
      The standard weight. This is the default value for WEIGHT.
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    • WEIGHT_SEMIBOLD

      public static final Float WEIGHT_SEMIBOLD
      A moderately heavier weight than WEIGHT_REGULAR.
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    • WEIGHT_MEDIUM

      public static final Float WEIGHT_MEDIUM
      An intermediate weight between WEIGHT_REGULAR and WEIGHT_BOLD.
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    • WEIGHT_DEMIBOLD

      public static final Float WEIGHT_DEMIBOLD
      A moderately lighter weight than WEIGHT_BOLD.
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    • WEIGHT_BOLD

      public static final Float WEIGHT_BOLD
      The standard bold weight.
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    • WEIGHT_HEAVY

      public static final Float WEIGHT_HEAVY
      A moderately heavier weight than WEIGHT_BOLD.
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    • WEIGHT_EXTRABOLD

      public static final Float WEIGHT_EXTRABOLD
      An extra heavy weight.
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    • WEIGHT_ULTRABOLD

      public static final Float WEIGHT_ULTRABOLD
      The heaviest predefined weight.
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    • WIDTH

      public static final TextAttribute WIDTH
      Attribute key for the width of a font. Values are instances of Number. The default value is WIDTH_REGULAR.

      Several constant values are provided, see WIDTH_CONDENSED, WIDTH_SEMI_CONDENSED, WIDTH_REGULAR, WIDTH_SEMI_EXTENDED, WIDTH_EXTENDED.

      The value is roughly the ratio of the advance width to that of the regular width.

      The system can interpolate the provided value.

    • WIDTH_CONDENSED

      public static final Float WIDTH_CONDENSED
      The most condensed predefined width.
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    • WIDTH_SEMI_CONDENSED

      public static final Float WIDTH_SEMI_CONDENSED
      A moderately condensed width.
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    • WIDTH_REGULAR

      public static final Float WIDTH_REGULAR
      The standard width. This is the default value for WIDTH.
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    • WIDTH_SEMI_EXTENDED

      public static final Float WIDTH_SEMI_EXTENDED
      A moderately extended width.
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    • WIDTH_EXTENDED

      public static final Float WIDTH_EXTENDED
      The most extended predefined width.
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    • POSTURE

      public static final TextAttribute POSTURE
      Attribute key for the posture of a font. Values are instances of Number. The default value is POSTURE_REGULAR.

      Two constant values are provided, POSTURE_REGULAR and POSTURE_OBLIQUE. The value POSTURE_OBLIQUE corresponds to the style value Font.ITALIC as passed to the Font constructor.

      The value is roughly the slope of the stems of the font, expressed as the run over the rise. Positive values lean right.

      The system can interpolate the provided value.

      This will affect the font's italic angle as returned by Font.getItalicAngle.

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    • POSTURE_REGULAR

      public static final Float POSTURE_REGULAR
      The standard posture, upright. This is the default value for POSTURE.
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    • POSTURE_OBLIQUE

      public static final Float POSTURE_OBLIQUE
      The standard italic posture.
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    • SIZE

      public static final TextAttribute SIZE
      Attribute key for the font size. Values are instances of Number. The default value is 12pt.

      This corresponds to the size parameter to the Font constructor.

      Very large or small sizes will impact rendering performance, and the rendering system might not render text at these sizes. Negative sizes are illegal and result in the default size.

      Note that the appearance and metrics of a 12pt font with a 2x transform might be different than that of a 24 point font with no transform.

    • TRANSFORM

      public static final TextAttribute TRANSFORM
      Attribute key for the transform of a font. Values are instances of TransformAttribute. The default value is TransformAttribute.IDENTITY.

      The TransformAttribute class defines the constant IDENTITY.

      This corresponds to the transform passed to Font.deriveFont(AffineTransform). Since that transform is mutable and TextAttribute values must not be, the TransformAttribute wrapper class is used.

      The primary intent is to support scaling and skewing, though other effects are possible.

      Some transforms will cause the baseline to be rotated and/or shifted. The text and the baseline are transformed together so that the text follows the new baseline. For example, with text on a horizontal baseline, the new baseline follows the direction of the unit x vector passed through the transform. Text metrics are measured against this new baseline. So, for example, with other things being equal, text rendered with a rotated TRANSFORM and an unrotated TRANSFORM will measure as having the same ascent, descent, and advance.

      In styled text, the baselines for each such run are aligned one after the other to potentially create a non-linear baseline for the entire run of text. For more information, see TextLayout.getLayoutPath().

      See Also:

    • SUPERSCRIPT

      public static final TextAttribute SUPERSCRIPT
      Attribute key for superscripting and subscripting. Values are instances of Integer. The default value is 0, which means that no superscript or subscript is used.

      Two constant values are provided, see SUPERSCRIPT_SUPER and SUPERSCRIPT_SUB. These have the values 1 and -1 respectively. Values of greater magnitude define greater levels of superscript or subscripting, for example, 2 corresponds to super-superscript, 3 to super-super-superscript, and similarly for negative values and subscript, up to a level of 7 (or -7). Values beyond this range are reserved; behavior is platform-dependent.

      SUPERSCRIPT can impact the ascent and descent of a font. The ascent and descent can never become negative, however.

    • SUPERSCRIPT_SUPER

      public static final Integer SUPERSCRIPT_SUPER
      Standard superscript.
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    • SUPERSCRIPT_SUB

      public static final Integer SUPERSCRIPT_SUB
      Standard subscript.
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    • FONT

      public static final TextAttribute FONT
      Attribute key used to provide the font to use to render text. Values are instances of Font. The default value is null, indicating that normal resolution of a Font from attributes should be performed.

      TextLayout and AttributedCharacterIterator work in terms of Maps of TextAttributes. Normally, all the attributes are examined and used to select and configure a Font instance. If a FONT attribute is present, though, its associated Font will be used. This provides a way for users to override the resolution of font attributes into a Font, or force use of a particular Font instance. This also allows users to specify subclasses of Font in cases where a Font can be subclassed.

      FONT is used for special situations where clients already have a Font instance but still need to use Map-based APIs. Typically, there will be no other attributes in the Map except the FONT attribute. With Map-based APIs the common case is to specify all attributes individually, so FONT is not needed or desirable.

      However, if both FONT and other attributes are present in the Map, the rendering system will merge the attributes defined in the Font with the additional attributes. This merging process classifies TextAttributes into two groups. One group, the 'primary' group, is considered fundamental to the selection and metric behavior of a font. These attributes are FAMILY, WEIGHT, WIDTH, POSTURE, SIZE, TRANSFORM, SUPERSCRIPT, and TRACKING. The other group, the 'secondary' group, consists of all other defined attributes, with the exception of FONT itself.

      To generate the new Map, first the Font is obtained from the FONT attribute, and all of its attributes extracted into a new Map. Then only the secondary attributes from the original Map are added to those in the new Map. Thus the values of primary attributes come solely from the Font, and the values of secondary attributes originate with the Font but can be overridden by other values in the Map.

      Note:Font's Map-based constructor and deriveFont methods do not process the FONT attribute, as these are used to create new Font objects. Instead, Font.getFont(Map) should be used to handle the FONT attribute.

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    • CHAR_REPLACEMENT

      public static final TextAttribute CHAR_REPLACEMENT
      Attribute key for a user-defined glyph to display in lieu of the font's standard glyph for a character. Values are instances of GraphicAttribute. The default value is null, indicating that the standard glyphs provided by the font should be used.

      This attribute is used to reserve space for a graphic or other component embedded in a line of text. It is required for correct positioning of 'inline' components within a line when bidirectional reordering (see Bidi) is performed. Each character (Unicode code point) will be rendered using the provided GraphicAttribute. Typically, the characters to which this attribute is applied should be \uFFFC.

      The GraphicAttribute determines the logical and visual bounds of the text; the actual Font values are ignored.

      See Also:

    • FOREGROUND

      public static final TextAttribute FOREGROUND
      Attribute key for the paint used to render the text. Values are instances of Paint. The default value is null, indicating that the Paint set on the Graphics2D at the time of rendering is used.

      Glyphs will be rendered using this Paint regardless of the Paint value set on the Graphics (but see SWAP_COLORS).

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    • BACKGROUND

      public static final TextAttribute BACKGROUND
      Attribute key for the paint used to render the background of the text. Values are instances of Paint. The default value is null, indicating that the background should not be rendered.

      The logical bounds of the text will be filled using this Paint, and then the text will be rendered on top of it (but see SWAP_COLORS).

      The visual bounds of the text is extended to include the logical bounds, if necessary. The outline is not affected.

      See Also:

    • UNDERLINE

      public static final TextAttribute UNDERLINE
      Attribute key for underline. Values are instances of Integer. The default value is -1, which means no underline.

      The constant value UNDERLINE_ON is provided.

      The underline affects both the visual bounds and the outline of the text.

    • UNDERLINE_ON

      public static final Integer UNDERLINE_ON
      Standard underline.
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    • STRIKETHROUGH

      public static final TextAttribute STRIKETHROUGH
      Attribute key for strikethrough. Values are instances of Boolean. The default value is false, which means no strikethrough.

      The constant value STRIKETHROUGH_ON is provided.

      The strikethrough affects both the visual bounds and the outline of the text.

    • STRIKETHROUGH_ON

      public static final Boolean STRIKETHROUGH_ON
      A single strikethrough.
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    • RUN_DIRECTION

      public static final TextAttribute RUN_DIRECTION
      Attribute key for the run direction of the line. Values are instances of Boolean. The default value is null, which indicates that the standard Bidi algorithm for determining run direction should be used with the value Bidi.DIRECTION_DEFAULT_LEFT_TO_RIGHT.

      The constants RUN_DIRECTION_RTL and RUN_DIRECTION_LTR are provided.

      This determines the value passed to the Bidi constructor to select the primary direction of the text in the paragraph.

      Note: This attribute should have the same value for all the text in a paragraph, otherwise the behavior is undetermined.

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    • RUN_DIRECTION_LTR

      public static final Boolean RUN_DIRECTION_LTR
      Left-to-right run direction.
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    • RUN_DIRECTION_RTL

      public static final Boolean RUN_DIRECTION_RTL
      Right-to-left run direction.
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    • BIDI_EMBEDDING

      public static final TextAttribute BIDI_EMBEDDING
      Attribute key for the embedding level of the text. Values are instances of Integer. The default value is null, indicating that the Bidirectional algorithm should run without explicit embeddings.

      Positive values 1 through 61 are embedding levels, negative values -1 through -61 are override levels. The value 0 means that the base line direction is used. These levels are passed in the embedding levels array to the Bidi constructor.

      Note: When this attribute is present anywhere in a paragraph, then any Unicode bidi control characters (RLO, LRO, RLE, LRE, and PDF) in the paragraph are disregarded, and runs of text where this attribute is not present are treated as though it were present and had the value 0.

      See Also:

    • JUSTIFICATION

      public static final TextAttribute JUSTIFICATION
      Attribute key for the justification of a paragraph. Values are instances of Number. The default value is 1, indicating that justification should use the full width provided. Values are pinned to the range [0..1].

      The constants JUSTIFICATION_FULL and JUSTIFICATION_NONE are provided.

      Specifies the fraction of the extra space to use when justification is requested on a TextLayout. For example, if the line is 50 points wide and it is requested to justify to 70 points, a value of 0.75 will pad to use three-quarters of the remaining space, or 15 points, so that the resulting line will be 65 points in length.

      Note: This should have the same value for all the text in a paragraph, otherwise the behavior is undetermined.

      See Also:

    • JUSTIFICATION_FULL

      public static final Float JUSTIFICATION_FULL
      Justify the line to the full requested width. This is the default value for JUSTIFICATION.
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    • JUSTIFICATION_NONE

      public static final Float JUSTIFICATION_NONE
      Do not allow the line to be justified.
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    • INPUT_METHOD_HIGHLIGHT

      public static final TextAttribute INPUT_METHOD_HIGHLIGHT
      Attribute key for input method highlight styles.

      Values are instances of InputMethodHighlight or Annotation. The default value is null, which means that input method styles should not be applied before rendering.

      If adjacent runs of text with the same InputMethodHighlight need to be rendered separately, the InputMethodHighlights should be wrapped in Annotation instances.

      Input method highlights are used while text is being composed by an input method. Text editing components should retain them even if they generally only deal with unstyled text, and make them available to the drawing routines.

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    • INPUT_METHOD_UNDERLINE

      public static final TextAttribute INPUT_METHOD_UNDERLINE
      Attribute key for input method underlines. Values are instances of Integer. The default value is -1, which means no underline.

      Several constant values are provided, see UNDERLINE_LOW_ONE_PIXEL, UNDERLINE_LOW_TWO_PIXEL, UNDERLINE_LOW_DOTTED, UNDERLINE_LOW_GRAY, and UNDERLINE_LOW_DASHED.

      This may be used in conjunction with UNDERLINE if desired. The primary purpose is for use by input methods. Other use of these underlines for simple ornamentation might confuse users.

      The input method underline affects both the visual bounds and the outline of the text.

      Since:
      1.3

    • UNDERLINE_LOW_ONE_PIXEL

      public static final Integer UNDERLINE_LOW_ONE_PIXEL
      Single pixel solid low underline.
      Since:
      1.3
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    • UNDERLINE_LOW_TWO_PIXEL

      public static final Integer UNDERLINE_LOW_TWO_PIXEL
      Double pixel solid low underline.
      Since:
      1.3
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    • UNDERLINE_LOW_DOTTED

      public static final Integer UNDERLINE_LOW_DOTTED
      Single pixel dotted low underline.
      Since:
      1.3
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    • UNDERLINE_LOW_GRAY

      public static final Integer UNDERLINE_LOW_GRAY
      Double pixel gray low underline.
      Since:
      1.3
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    • UNDERLINE_LOW_DASHED

      public static final Integer UNDERLINE_LOW_DASHED
      Single pixel dashed low underline.
      Since:
      1.3
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    • SWAP_COLORS

      public static final TextAttribute SWAP_COLORS
      Attribute key for swapping foreground and background Paints. Values are instances of Boolean. The default value is false, which means do not swap colors.

      The constant value SWAP_COLORS_ON is defined.

      If the FOREGROUND attribute is set, its Paint will be used as the background, otherwise the Paint currently on the Graphics will be used. If the BACKGROUND attribute is set, its Paint will be used as the foreground, otherwise the system will find a contrasting color to the (resolved) background so that the text will be visible.

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    • SWAP_COLORS_ON

      public static final Boolean SWAP_COLORS_ON
      Swap foreground and background.
      Since:
      1.3
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    • NUMERIC_SHAPING

      public static final TextAttribute NUMERIC_SHAPING
      Attribute key for converting ASCII decimal digits to other decimal ranges. Values are instances of NumericShaper. The default is null, which means do not perform numeric shaping.

      When a numeric shaper is defined, the text is first processed by the shaper before any other analysis of the text is performed.

      Note: This should have the same value for all the text in the paragraph, otherwise the behavior is undetermined.

      Since:
      1.4
      See Also:

    • KERNING

      public static final TextAttribute KERNING
      Attribute key to request kerning. Values are instances of Integer. The default value is 0, which does not request kerning.

      The constant value KERNING_ON is provided.

      The default advances of single characters are not appropriate for some character sequences, for example "To" or "AWAY". Without kerning the adjacent characters appear to be separated by too much space. Kerning causes selected sequences of characters to be spaced differently for a more pleasing visual appearance.

      Since:
      1.6

    • KERNING_ON

      public static final Integer KERNING_ON
      Request standard kerning.
      Since:
      1.6
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    • LIGATURES

      public static final TextAttribute LIGATURES
      Attribute key for enabling optional ligatures. Values are instances of Integer. The default value is 0, which means do not use optional ligatures.

      The constant value LIGATURES_ON is defined.

      Ligatures required by the writing system are always enabled.

      Since:
      1.6

    • LIGATURES_ON

      public static final Integer LIGATURES_ON
      Request standard optional ligatures.
      Since:
      1.6
      See Also:

    • TRACKING

      public static final TextAttribute TRACKING
      Attribute key to control tracking. Values are instances of Number. The default value is 0, which means no additional tracking.

      The constant values TRACKING_TIGHT and TRACKING_LOOSE are provided.

      The tracking value is multiplied by the font point size and passed through the font transform to determine an additional amount to add to the advance of each glyph cluster. Positive tracking values will inhibit formation of optional ligatures. Tracking values are typically between -0.1 and 0.3; values outside this range are generally not desirable.

      Since:
      1.6

    • TRACKING_TIGHT

      public static final Float TRACKING_TIGHT
      Perform tight tracking.
      Since:
      1.6
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    • TRACKING_LOOSE

      public static final Float TRACKING_LOOSE
      Perform loose tracking.
      Since:
      1.6
      See Also:

  • Constructor Details

    • TextAttribute

      protected TextAttribute(String name)
      Constructs a TextAttribute with the specified name.
      Parameters:
      name - the attribute name to assign to this TextAttribute

  • Method Details