Class java.awt.font.TextAttribute

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Class java.awt.font.TextAttribute

java.lang.Object
  |
  +--java.text.AttributedCharacterIterator.Attribute
        |
        +--java.awt.font.TextAttribute

public final class TextAttribute
extends AttributedCharacterIterator.Attribute

Defines attribute keys and attribute values used for text rendering. TextAttribute instances are used as attribute keys to identify attributes in AttributedCharacterIterator, Font, and other classes handling text attributes. Other constants defined in this class are used as attribute values. For each text attribute, the documentation describes:

the type of their values,
the valid values if there are limitations
relevant constants
the default effect if the attribute is absent (or has a null value).
a description of the effect.
the fallback behavior if the exact attribute requested is not available.

Types of Values

The values of attributes must always be immutable.
Where a list of limitations is given, then any value outside of that set is reserved for future use, and ignored at present.
If the value is null (or not of the proper type), then it has the default effect. The effect of a particular value may be interpolated, especially in the case of multiple master fonts. This interpolation is done based on the nearest defined constants above and below the request:

interpolation = (request - below)/(above - below);

Interpolation

Fonts should interpolate values in certain circumstances. For example, suppose that the WEIGHT value is 2.13. If the nearest surrounding values in the font are WEIGHT_BOLD = 2.0 and WEIGHT_HEAVY = 2.25, then font would then interpret the WEIGHT request as being 52% of the way between what it considers BOLD and what it considers HEAVY. If the nearest surrounding values are WEIGHT_SEMIBOLD = 1.25 and WEIGHT_ULTRABOLD = 2.75, then the WEIGHT request is interpreted as being 58.67% of the way between SEMIBOLD and ULTRABOLD.
Where a Font does not have enough capability to handle a given request, such as superscript, then it should simulate it to the best of its ability. If the client wishes to determine whether that is being done, then she should query the font to see what were the actual attributes used.

See Also:: AttributedCharacterIterator, Font, Serialized Form

Field Summary
static TextAttribute	BACKGROUND
static TextAttribute	BIDI_EMBEDDING Attribute key for the embedding level for nested bidirectional runs.
static TextAttribute	CHAR_REPLACEMENT Attribute key for a user_defined glyph to display in the text in lieu of a character.
static TextAttribute	FAMILY Attribute key for the unlocalized font family name.
static TextAttribute	FONT Attribute key for the font to use to render text.
static TextAttribute	FOREGROUND Attribute key for the foreground color adornment.
static TextAttribute	INPUT_METHOD_HIGHLIGHT Attribute key for input method highlight styles.
static TextAttribute	JUSTIFICATION Attribute key for the justification of a paragraph.
static Float	JUSTIFICATION_FULL Justify the line to the full requested width.
static Float	JUSTIFICATION_NONE Do not allow the line to be justified.
static TextAttribute	POSTURE Attribute key for the posture of a font.
static Float	POSTURE_OBLIQUE The standard italic posture.
static Float	POSTURE_REGULAR The standard posture, upright.
static TextAttribute	RUN_DIRECTION Attribute key for the run direction of the line.
static Boolean	RUN_DIRECTION_LTR Left-to-right run direction.
static Boolean	RUN_DIRECTION_RTL Right-to-left run direction.
static TextAttribute	SIZE Attribute key for the font size.
static TextAttribute	STRIKETHROUGH Attribute key for the strikethrough adornment.
static Boolean	STRIKETHROUGH_ON A single strikethrough.
static TextAttribute	SUPERSCRIPT Attribute key for super and subscripting.
static Integer	SUPERSCRIPT_SUB Standard subscript.
static Integer	SUPERSCRIPT_SUPER Standard superscript.
static TextAttribute	SWAP_COLORS Attribute key for swapping foreground and background colors.
static Boolean	SWAP_COLORS_ON Swap foreground and background colors.
static TextAttribute	TRANSFORM Attribute key for the transform of a font.
static TextAttribute	UNDERLINE Attribute key for underline adornments.
static Integer	UNDERLINE_ON Standard underline at the roman baseline for roman text, and below the decenders for other text.
static TextAttribute	WEIGHT Attribute key for the weight of a font.
static Float	WEIGHT_BOLD The standard bold weight.
static Float	WEIGHT_DEMIBOLD A moderately lighter weight than BOLD.
static Float	WEIGHT_DEMILIGHT An intermediate weight between LIGHT and STANDARD.
static Float	WEIGHT_EXTRA_LIGHT The lightest predefined weight.
static Float	WEIGHT_EXTRABOLD An extra heavy weight.
static Float	WEIGHT_HEAVY A moderately heavier weight than BOLD.
static Float	WEIGHT_LIGHT The standard light weight.
static Float	WEIGHT_MEDIUM An intermediate weight between the REGULAR and BOLD weights.
static Float	WEIGHT_REGULAR The standard weight.
static Float	WEIGHT_SEMIBOLD A moderately heavier weight than REGULAR.
static Float	WEIGHT_ULTRABOLD The heaviest predefined weight.
static TextAttribute	WIDTH Attribute key for the width of a font.
static Float	WIDTH_CONDENSED The most condensed predefined width.
static Float	WIDTH_EXTENDED The most extended predefined width.
static Float	WIDTH_REGULAR The standard width.
static Float	WIDTH_SEMI_CONDENSED A moderately condensed width.
static Float	WIDTH_SEMI_EXTENDED A moderately extended width.

Fields inherited from class java.text.AttributedCharacterIterator.Attribute
INPUT_METHOD_SEGMENT , LANGUAGE , READING

Constructor Summary
TextAttribute(String name) Constructs a TextAttribute with the given name.

Method Summary
protected Object	readResolve() Resolves instances being deserialized to the predefined constants.

Methods inherited from class java.text.AttributedCharacterIterator.Attribute
equals , getName , hashCode , toString

Methods inherited from class java.lang.Object
clone , finalize , getClass , notify , notifyAll , wait , wait , wait

Field Detail

FAMILY

public static final TextAttribute FAMILY

Attribute key for the unlocalized font family name.

Key	FAMILY
Value	String
Constants	"Serif", "SansSerif"
Default	Host default;
Description	The name of the font family. If the family name is not found, the default font is used. The name should not be the full font name or specify other attributes (such as the name "Helvetica Bold"). Such names will (most likely) result in the default font since the name won't match a known family name.

WEIGHT

public static final TextAttribute WEIGHT

Attribute key for the weight of a font.

Key	WEIGHT
Value	Float
Constants	WEIGHT_ULTRA_LIGHT = 0.25, WEIGHT_EXTRA_LIGHT = 0.5, WEIGHT_LIGHT = 0.75, WEIGHT_DEMILIGHT = 0.875, WEIGHT_REGULAR = 1.0, WEIGHT_SEMIBOLD = 1.25, WEIGHT_MEDIUM = 1.5, WEIGHT_DEMIBOLD = 1.75, WEIGHT_BOLD = 2.0, WEIGHT_HEAVY = 2.25, WEIGHT_EXTRABOLD = 2.5, WEIGHT_ULTRABOLD = 2.75
Default	WEIGHT_REGULAR
Description	The value is roughly the ratio of the stem width to that of the regular weight. If the font has a different value for specific constants, then the value is interpolated as described in the class description.
Fallback	Currently none. However, in the future, shape manipulations may be available to simulate weight variations for fonts that don't have them.

WEIGHT_EXTRA_LIGHT

public static final Float WEIGHT_EXTRA_LIGHT

The lightest predefined weight.

See Also:: WEIGHT

WEIGHT_LIGHT

public static final Float WEIGHT_LIGHT

The standard light weight.

See Also:: WEIGHT

WEIGHT_DEMILIGHT

public static final Float WEIGHT_DEMILIGHT

An intermediate weight between LIGHT and STANDARD.

See Also:: WEIGHT

WEIGHT_REGULAR

public static final Float WEIGHT_REGULAR

The standard weight. This weight is used if WEIGHT is unspecified.

See Also:: WEIGHT

WEIGHT_SEMIBOLD

public static final Float WEIGHT_SEMIBOLD

A moderately heavier weight than REGULAR.

See Also:: WEIGHT

WEIGHT_MEDIUM

public static final Float WEIGHT_MEDIUM

An intermediate weight between the REGULAR and BOLD weights.

See Also:: WEIGHT

WEIGHT_DEMIBOLD

public static final Float WEIGHT_DEMIBOLD

A moderately lighter weight than BOLD.

See Also:: WEIGHT

WEIGHT_BOLD

public static final Float WEIGHT_BOLD

The standard bold weight.

See Also:: WEIGHT

WEIGHT_HEAVY

public static final Float WEIGHT_HEAVY

A moderately heavier weight than BOLD.

See Also:: WEIGHT

WEIGHT_EXTRABOLD

public static final Float WEIGHT_EXTRABOLD

An extra heavy weight.

See Also:: WEIGHT

WEIGHT_ULTRABOLD

public static final Float WEIGHT_ULTRABOLD

The heaviest predefined weight.

See Also:: WEIGHT

WIDTH

public static final TextAttribute WIDTH

Attribute key for the width of a font.

Key	WIDTH
Value	Float
Constants	WIDTH_CONDENSED = 0.75, WIDTH_SEMI_CONDENSED = 0.875, WIDTH_REGULAR = 1.0, WIDTH_SEMI_EXTENDED = 1.25, WIDTH_EXTENDED = 1.5
Default	WIDTH_REGULAR
Description	The value is roughly the ration of the advance width to that of the regular width. If the font has a different value for specific constants, then the value is interpolated as described in the class description.
Fallback	If a Narrow font is available and matches, use that. Otherwise scale with a transform based on the value.

WIDTH_CONDENSED

public static final Float WIDTH_CONDENSED

The most condensed predefined width.

See Also:: WIDTH

WIDTH_SEMI_CONDENSED

public static final Float WIDTH_SEMI_CONDENSED

A moderately condensed width.

See Also:: WIDTH

WIDTH_REGULAR

public static final Float WIDTH_REGULAR

The standard width. This width is used if WIDTH is unspecified.

See Also:: WIDTH

WIDTH_SEMI_EXTENDED

public static final Float WIDTH_SEMI_EXTENDED

A moderately extended width.

See Also:: WIDTH

WIDTH_EXTENDED

public static final Float WIDTH_EXTENDED

The most extended predefined width.

See Also:: WIDTH

POSTURE

public static final TextAttribute POSTURE

Attribute key for the posture of a font.

Key	POSTURE
Value	Float
Constants	POSTURE_REGULAR = 0, POSTURE_OBLIQUE = 0.20
Default	POSTURE_REGULAR
Description	The value is interpreted generally as a skew slope, positive leans to the right. If the font has a different value for specific constants, then the value is interpolated as described in the class description. With fonts that have italic faces, not only the skew of the character will change, but also the letter shapes may change. Notes: To set the value by angle, use: `value = new Float(Math.tan(Math.PIdegrees/180.0)` To determine the angle from the value, use: `angle = Math.atan(value.floatValue())180/Math.PI`
Fallback	If an Oblique font is available and matches, use that. Otherwise skew with a transform using the posture value interpreted as run/rise.

See Also:: Font#getItalicAngle

POSTURE_REGULAR

public static final Float POSTURE_REGULAR

The standard posture, upright.

See Also:: POSTURE

POSTURE_OBLIQUE

public static final Float POSTURE_OBLIQUE

The standard italic posture.

See Also:: POSTURE

SIZE

public static final TextAttribute SIZE

Attribute key for the font size.

Key	SIZE
Value	Float
Default	from System Properties
Description	Represents point size. Note that the appearance and metrics of a 12pt font with a 2X transform may be different than that of a 24 point font with no transform.
Fallback	Scale to provided size.

TRANSFORM

public static final TextAttribute TRANSFORM

Attribute key for the transform of a font.

Key	TRANSFORM
Value	TransformAttribute
Default	Identity transform
Description	Used to transform glyphs rendered by this font. The primary intent is to support scaling, skewing, and translation. In general, large rotations will not produce very useful results. The transform modifies both the glyph and the advance. The translations in the transform are interpreted as a ratio of the point size. That is, with a point size of 12, a translation of 0.5 will result in a movement of 6 points. The advance point of the transformed glyph is the transform of the advance point projected onto the baseline. If the advance ends up to the left (top) of the glyph origin, the two points are swapped. Example one: suppose the point size is 20, the original advance is 10.0, and the transform is a 60 degree counterclockwise rotation plus an offset up and to the right of 0.1, -0.1. The translation results in an offset of <2.0, -2.0>. The original advance point is <10.0, 0.0>; after the rotation it is <6.0, -8.0>; adding the offset this becomes <8.0, -10.0>, projecting on the (horizontal) baseline this becomes the new advance point: <8.0, 0.0>. The advance width is the distance from the origin to the advance point: 8.0. The rotated glyph will draw two points up and to the right of its origin (and be rotated). This does not affect the baseline for subsequent glyphs.

SUPERSCRIPT

public static final TextAttribute SUPERSCRIPT

Attribute key for super and subscripting.

Key	SUPERSCRIPT
Value	Integer
Constants	SUPERSCRIPT_NONE = 0, SUPERSCRIPT_SUPER = 1, SUPERSCRIPT_SUB = -1
Default	SUPERSCRIPT_NONE
Description	Requests that the font display the characters with glyphs at a particular superscript level: 0 = none, 1 = superscript, 2 = superscript of superscript,...-1 = subscript, -2 = subscript of subscript,... Requests that the font display text using default superscript (or subscript) glyphs and/or scaling.
Fallback	Use transform with translation of +/-1/2 and scale of 2/3, progressively for each level. That is, for the transform at level N (with N != 0): `offset = sign(N)1/2(2/3)^(abs(N)-1) scale = (2/3)^abs(N)`

SUPERSCRIPT_SUPER

public static final Integer SUPERSCRIPT_SUPER

Standard superscript.

See Also:: SUPERSCRIPT

SUPERSCRIPT_SUB

public static final Integer SUPERSCRIPT_SUB

Standard subscript.

See Also:: SUPERSCRIPT

FONT

public static final TextAttribute FONT

Attribute key for the font to use to render text.

Key	FONT
Value	Font
Default	None, perform default resolution
Description	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 (with subclassible fonts) users to specify subclasses of Font.

CHAR_REPLACEMENT

public static final TextAttribute CHAR_REPLACEMENT

Attribute key for a user_defined glyph to display in the text in lieu of a character.

Key	CHAR_REPLACEMENT
Value	GraphicAttribute
Description	Allows the user to specify an empty position plus metric information. Used to reserve space for a graphic or other embedded component. Required for correct BIDI position of 'inline' components within a line. An optional convenience method allows drawing for simple cases. Follows the Microsoft model: the character that this is applied to should be ?.

FOREGROUND

public static final TextAttribute FOREGROUND

Attribute key for the foreground color adornment.

Key	FOREGROUND
Value	Color
Default	Black
Description	Specify the foreground color of the text.

BACKGROUND

public static final TextAttribute BACKGROUND

UNDERLINE

public static final TextAttribute UNDERLINE

Attribute key for underline adornments.

Key	UNDERLINE
Value	Integer
Constants	UNDERLINE_ON = 0
Default	none
Description	An embellishment added to the glyphs rendered by a font.
Fallback

UNDERLINE_ON

public static final Integer UNDERLINE_ON

Standard underline at the roman baseline for roman text, and below the decenders for other text.

See Also:: UNDERLINE

STRIKETHROUGH

public static final TextAttribute STRIKETHROUGH

Attribute key for the strikethrough adornment.

Key	STRIKETHROUGH
Value	Boolean
Constants	true = on, false = off
Default	off
Description	An embellishment added to the glyphs rendered by a font.

STRIKETHROUGH_ON

public static final Boolean STRIKETHROUGH_ON

A single strikethrough.

See Also:: STRIKETHROUGH

RUN_DIRECTION

public static final TextAttribute RUN_DIRECTION

Attribute key for the run direction of the line.

Key	RUN_DIRECTION
Value	Boolean
Constants	RUN_DIRECTION_LTR = true, RUN_DIRECTION_RTL = false
Default	Use the default Unicode base direction from the BIDI algorithm.
Description	Specifies which base run direction to use when positioning mixed directional runs within a paragraph. If this value is RUN_DIRECTION_DEFAULT, TextLayout uses the default Unicode base direction from the BIDI algorithm. This attribute should have the same value over the whole paragraph.

RUN_DIRECTION_LTR

public static final Boolean RUN_DIRECTION_LTR

Left-to-right run direction.

See Also:: RUN_DIRECTION

RUN_DIRECTION_RTL

public static final Boolean RUN_DIRECTION_RTL

Right-to-left run direction.

See Also:: RUN_DIRECTION

BIDI_EMBEDDING

public static final TextAttribute BIDI_EMBEDDING

Attribute key for the embedding level for nested bidirectional runs.

Key	BIDI_EMBEDDING
Value	Integer
Limits	Positive values 1 through 15 are embedding levels, negative values through -15 are override levels
Default	Use standard BIDI to compute levels from formatting characters in the text.
Description	Specifies the bidi embedding level of the character. When this attribute is present anywhere in a paragraph, then the Unicode characters RLO, LRO, RLE, LRE, PDF are disregarded in the BIDI analysis of that paragraph. See the Unicode Standard v. 2.0, section 3-11.

JUSTIFICATION

public static final TextAttribute JUSTIFICATION

Attribute key for the justification of a paragraph.

Key	JUSTIFICATION
Value	Float
Limits	0.0 through1.0
Default	1.0
Description	Specifies which fraction of the extra space to use when justification is requested. For example, if the line is 50 points wide and the margins are 70 points apart, a value of 0.5 means that the line will be padded to reach a width of 60 points. This attribute should have the same value over the whole paragraph.

JUSTIFICATION_FULL

public static final Float JUSTIFICATION_FULL

Justify the line to the full requested width.

See Also:: JUSTIFICATION

JUSTIFICATION_NONE

public static final Float JUSTIFICATION_NONE

Do not allow the line to be justified.

See Also:: JUSTIFICATION

INPUT_METHOD_HIGHLIGHT

public static final TextAttribute INPUT_METHOD_HIGHLIGHT

Attribute key for input method highlight styles.

Values are instances of InputMethodHighlight. These instances should be wrapped in Annotation instances if segments need to be highlighted separately.

Input method highlights are used while text is being composed using 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.

See Also:: InputMethodHighlight

SWAP_COLORS

public static final TextAttribute SWAP_COLORS

Attribute key for swapping foreground and background colors.

Values are instances of Boolean. The default is not to swap the colors. If the foreground and backround color attributes are both defined, this causes them to be swapped when rendering text. If either is defaulted the exact effect is undefined--generally it will produce an 'inverted' appearance.

SWAP_COLORS_ON

public static final Boolean SWAP_COLORS_ON

Swap foreground and background colors.

Constructor Detail

TextAttribute

protected TextAttribute(String name)

Constructs a TextAttribute with the given name.

Method Detail

readResolve

protected Object readResolve()
                      throws InvalidObjectException

Resolves instances being deserialized to the predefined constants.

Overrides:: readResolve in class AttributedCharacterIterator.Attribute