Java(TM) 2 Platform, Standard Edition, v1.2.2 API Specification: Class LineMetrics - JDK 5 Documentation v1.2.2, Java 2 SDK 英文文档

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Java^TM 2 Platform
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java.awt.font
Class LineMetrics

java.lang.Object
  |
  +--java.awt.font.LineMetrics

public abstract class LineMetrics
extends Object

The LineMetrics class allows access to the metrics needed to layout characters along a line and to layout of a set of lines. A LineMetrics object encapsulates the measurement information associated with a run of text.

Fonts can have different metrics for different ranges of characters. The getLineMetrics methods of Font take some text as an argument and return a LineMetrics object describing the metrics of the initial number of characters in that text, as returned by getNumChars().

Constructor Summary

LineMetrics()


Method Summary

abstract float getAscent()
          Returns the ascent of the text.

abstract int getBaselineIndex()
          Returns the baseline index of the text.

abstract float[] getBaselineOffsets()
          Returns the baseline offsets of the text, relative to the baseline of the text.

abstract float getDescent()
          Returns the descent of the text.

abstract float getHeight()
          Returns the height of the text.

abstract float getLeading()
          Returns the leading of the text.

abstract int getNumChars()
          Returns the number of characters in the text whose metrics are encapsulated by this LineMetrics object.

abstract float getStrikethroughOffset()
          Returns the position of the strike-through line relative to the baseline.

abstract float getStrikethroughThickness()
          Returns the thickness of the strike-through line.

abstract float getUnderlineOffset()
          Returns the position of the underline relative to the baseline.

abstract float getUnderlineThickness()
          Returns the thickness of the underline.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

LineMetrics

public LineMetrics()

Method Detail

getNumChars

public abstract int getNumChars()

Returns the number of characters in the text whose metrics are encapsulated by this LineMetrics object.

Returns:: the number of characters in the text with which this LineMetrics was created.

getAscent

public abstract float getAscent()

Returns the ascent of the text. The ascent is the distance from the baseline to the ascender line. The ascent usually represents the the height of the capital letters of the text. Some characters can extend above the ascender line.

Returns:: the ascent of the text.

getDescent

public abstract float getDescent()

Returns the descent of the text. The descent is the distance from the baseline to the descender line. The descent usually represents the distance to the bottom of lower case letters like 'p'. Some characters can extend below the descender line.

Returns:: the descent of the text.

getLeading

public abstract float getLeading()

Returns the leading of the text. The leading is the recommended distance from the bottom of the descender line to the top of the next line.

Returns:: the leading of the text.

getHeight

public abstract float getHeight()

Returns the height of the text. The height is equal to the sum of the ascent, the descent and the leading.

Returns:: the height of the text.

getBaselineIndex

public abstract int getBaselineIndex()

Returns the baseline index of the text. The index is one of ROMAN_BASELINE, CENTER_BASELINE, HANGING_BASELINE.

Returns:: the baseline of the text.

getBaselineOffsets

public abstract float[] getBaselineOffsets()

Returns the baseline offsets of the text, relative to the baseline of the text. The offsets are indexed by baseline index. For example, if the baseline index is CENTER_BASELINE then offsets[HANGING_BASELINE] is usually negative, offsets[CENTER_BASELINE] is zero, and offsets[ROMAN_BASELINE] is usually positive.

Returns:: the baseline offsets of the text.

getStrikethroughOffset

public abstract float getStrikethroughOffset()

Returns the position of the strike-through line relative to the baseline.

Returns:: the position of the strike-through line.

getStrikethroughThickness

public abstract float getStrikethroughThickness()

Returns the thickness of the strike-through line.

Returns:: the thickness of the strike-through line.

getUnderlineOffset

public abstract float getUnderlineOffset()

Returns the position of the underline relative to the baseline.

Returns:: the position of the underline.

getUnderlineThickness

public abstract float getUnderlineThickness()

Returns the thickness of the underline.

Returns:: the thickness of the underline.