java.lang.Object java.awt.FontMetrics
public abstract class FontMetrics
The FontMetrics
class defines a font metrics object, which encapsulates information about the rendering of a particular font on a particular screen.
Note to subclassers: Since many of these methods form closed, mutually recursive loops, you must take care that you implement at least one of the methods in each such loop to prevent infinite recursion when your subclass is used. In particular, the following is the minimal suggested set of methods to override in order to ensure correctness and prevent infinite recursion (though other subsets are equally feasible):
Note that the implementations of these methods are inefficient, so they are usually overridden with more efficient toolkit-specific implementations.
When an application asks AWT to place a character at the position (x, y), the character is placed so that its reference point (shown as the dot in the accompanying image) is put at that position. The reference point specifies a horizontal line called the baseline of the character. In normal printing, the baselines of characters should align.
In addition, every character in a font has an ascent, a descent, and an advance width. The ascent is the amount by which the character ascends above the baseline. The descent is the amount by which the character descends below the baseline. The advance width indicates the position at which AWT should place the next character.
An array of characters or a string can also have an ascent, a descent, and an advance width. The ascent of the array is the maximum ascent of any character in the array. The descent is the maximum descent of any character in the array. The advance width is the sum of the advance widths of each of the characters in the character array. The advance of a String
is the distance along the baseline of the String
. This distance is the width that should be used for centering or right-aligning the String
. Note that the advance of a String
is not necessarily the sum of the advances of its characters measured in isolation because the width of a character can vary depending on its context. For example, in Arabic text, the shape of a character can change in order to connect to other characters. Also, in some scripts, certain character sequences can be represented by a single shape, called a ligature. Measuring characters individually does not account for these transformations.
Font
, Serialized Form
protected Font
font
Font
from which the font metrics are created. Constructor Summary protected
FontMetrics(Font font)
FontMetrics
object for finding out height and width information about the specified Font
and specific character glyphs in that Font
. Method Summary int
bytesWidth(byte[] data, int off, int len)
Font
. int
charsWidth(char[] data, int off, int len)
Font
. int
charWidth(char ch)
Font
. int
charWidth(int codePoint)
Font
. int
getAscent()
Font
described by this FontMetrics
object. int
getDescent()
Font
described by this FontMetrics
object. Font
getFont()
Font
described by this FontMetrics
object. int
getHeight()
int
getLeading()
Font
described by this FontMetrics
object. LineMetrics
getLineMetrics(char[] chars, int beginIndex, int limit, Graphics context)
LineMetrics
object for the specified character array in the specified Graphics
context. LineMetrics
getLineMetrics(CharacterIterator ci, int beginIndex, int limit, Graphics context)
LineMetrics
object for the specified CharacterIterator
in the specified Graphics
context. LineMetrics
getLineMetrics(String str, Graphics context)
LineMetrics
object for the specified String
in the specified Graphics
context. LineMetrics
getLineMetrics(String str, int beginIndex, int limit, Graphics context)
LineMetrics
object for the specified String
in the specified Graphics
context. int
getMaxAdvance()
Font
. int
getMaxAscent()
Font
described by this FontMetrics
object. Rectangle2D
getMaxCharBounds(Graphics context)
Graphics
context. int
getMaxDecent()
getMaxDescent()
. int
getMaxDescent()
Font
described by this FontMetrics
object. Rectangle2D
getStringBounds(char[] chars, int beginIndex, int limit, Graphics context)
Graphics
context. Rectangle2D
getStringBounds(CharacterIterator ci, int beginIndex, int limit, Graphics context)
CharacterIterator
in the specified Graphics
context. Rectangle2D
getStringBounds(String str, Graphics context)
String
in the specified Graphics
context. Rectangle2D
getStringBounds(String str, int beginIndex, int limit, Graphics context)
String
in the specified Graphics
context. int[]
getWidths()
Font
. boolean
hasUniformLineMetrics()
Font
has uniform line metrics. int
stringWidth(String str)
String
in this Font
. String
toString()
FontMetrics
object's values as a String
. font
protected Font font
Font
from which the font metrics are created. This cannot be null.
getFont()
protected FontMetrics(Font font)
FontMetrics
object for finding out height and width information about the specified Font
and specific character glyphs in that Font
.
font
- the Font
Font
public Font getFont()
Font
described by this FontMetrics
object.
Font
described by this FontMetrics
object.
public int getLeading()
Font
described by this FontMetrics
object. The standard leading, or interline spacing, is the logical amount of space to be reserved between the descent of one line of text and the ascent of the next line. The height metric is calculated to include this extra space.
Font
.
getHeight()
, getAscent()
, getDescent()
public int getAscent()
Font
described by this FontMetrics
object. The font ascent is the distance from the font's baseline to the top of most alphanumeric characters. Some characters in the Font
might extend above the font ascent line.
Font
.
getMaxAscent()
public int getDescent()
Font
described by this FontMetrics
object. The font descent is the distance from the font's baseline to the bottom of most alphanumeric characters with descenders. Some characters in the Font
might extend below the font descent line.
Font
.
getMaxDescent()
public int getHeight()
getLeading()
, getAscent()
, getDescent()
public int getMaxAscent()
Font
described by this FontMetrics
object. No character extends further above the font's baseline than this height.
Font
.
getAscent()
public int getMaxDescent()
Font
described by this FontMetrics
object. No character extends further below the font's baseline than this height.
Font
.
getDescent()
@Deprecated public int getMaxDecent()
getMaxDescent()
.
Font
.
getMaxDescent()
public int getMaxAdvance()
Font
. The advance is the distance from the leftmost point to the rightmost point on the string's baseline. The advance of a String
is not necessarily the sum of the advances of its characters.
Font
, or -1
if the maximum advance width is not known.
public int charWidth(int codePoint)
Font
. The advance is the distance from the leftmost point to the rightmost point on the character's baseline. Note that the advance of a String
is not necessarily the sum of the advances of its characters.
This method doesn't validate the specified character to be a valid Unicode code point. The caller must validate the character value using Character.isValidCodePoint
if necessary.
codePoint
- the character (Unicode code point) to be measured
Font
described by this FontMetrics
object.
charsWidth(char[], int, int)
, stringWidth(String)
public int charWidth(char ch)
Font
. The advance is the distance from the leftmost point to the rightmost point on the character's baseline. Note that the advance of a String
is not necessarily the sum of the advances of its characters.
Note: This method cannot handle supplementary characters. To support all Unicode characters, including supplementary characters, use the charWidth(int)
method.
ch
- the character to be measured
Font
described by this FontMetrics
object.
charsWidth(char[], int, int)
, stringWidth(String)
public int stringWidth(String str)
String
in this Font
. The advance is the distance from the leftmost point to the rightmost point on the string's baseline.
Note that the total advance width returned from this method does not take into account the rendering context. Therefore, the anti-aliasing and fractional metrics hints can affect the value of the advance. When enabling the anti-aliasing and fractional metrics hints, use getStringBounds(String, Graphics)
instead of this method. The advance of a String
is not necessarily the sum of the advances of its characters.
str
- the String
to be measured
String
in the Font
described by this FontMetrics
.
bytesWidth(byte[], int, int)
, charsWidth(char[], int, int)
, getStringBounds(String, Graphics)
public int charsWidth(char[] data, int off, int len)
Font
. The advance is the distance from the leftmost point to the rightmost point on the string's baseline. The advance of a String
is not necessarily the sum of the advances of its characters. This is equivalent to measuring a String
of the characters in the specified range.
data
- the array of characters to be measured
off
- the start offset of the characters in the array
len
- the number of characters to be measured from the array
char
array in the font described by this FontMetrics
object.
charWidth(int)
, charWidth(char)
, bytesWidth(byte[], int, int)
, stringWidth(String)
public int bytesWidth(byte[] data, int off, int len)
Font
. The advance is the distance from the leftmost point to the rightmost point on the string's baseline. The advance of a String
is not necessarily the sum of the advances of its characters. This is equivalent to measuring a String
of the characters in the specified range.
data
- the array of bytes to be measured
off
- the start offset of the bytes in the array
len
- the number of bytes to be measured from the array
byte
array in the Font
described by this FontMetrics
object.
charsWidth(char[], int, int)
, stringWidth(String)
public int[] getWidths()
Font
. The advance is the distance from the leftmost point to the rightmost point on the character's baseline. Note that the advance of a String
is not necessarily the sum of the advances of its characters.
Font
described by this FontMetrics
object.
public boolean hasUniformLineMetrics()
Font
has uniform line metrics. A composite font may consist of several different fonts to cover various character sets. In such cases, the FontLineMetrics
objects are not uniform. Different fonts may have a different ascent, descent, metrics and so on. This information is sometimes necessary for line measuring and line breaking.
true
if the font has uniform line metrics; false
otherwise.
Font.hasUniformLineMetrics()
public LineMetrics getLineMetrics(String str, Graphics context)
LineMetrics
object for the specified String
in the specified Graphics
context.
str
- the specified String
context
- the specified Graphics
context
LineMetrics
object created with the specified String
and Graphics
context.
Font.getLineMetrics(String, FontRenderContext)
public LineMetrics getLineMetrics(String str, int beginIndex, int limit, Graphics context)
LineMetrics
object for the specified String
in the specified Graphics
context.
str
- the specified String
beginIndex
- the initial offset of str
limit
- the length of str
context
- the specified Graphics
context
LineMetrics
object created with the specified String
and Graphics
context.
Font.getLineMetrics(String, int, int, FontRenderContext)
public LineMetrics getLineMetrics(char[] chars, int beginIndex, int limit, Graphics context)
LineMetrics
object for the specified character array in the specified Graphics
context.
chars
- the specified character array
beginIndex
- the initial offset of chars
limit
- the length of chars
context
- the specified Graphics
context
LineMetrics
object created with the specified character array and Graphics
context.
Font.getLineMetrics(char[], int, int, FontRenderContext)
public LineMetrics getLineMetrics(CharacterIterator ci, int beginIndex, int limit, Graphics context)
LineMetrics
object for the specified CharacterIterator
in the specified Graphics
context.
ci
- the specified CharacterIterator
beginIndex
- the initial offset in ci
limit
- the end index of ci
context
- the specified Graphics
context
LineMetrics
object created with the specified arguments.
Font.getLineMetrics(CharacterIterator, int, int, FontRenderContext)
public Rectangle2D getStringBounds(String str, Graphics context)
String
in the specified Graphics
context. The bounds is used to layout the String
.
str
- the specified String
context
- the specified Graphics
context
Rectangle2D
that is the bounding box of the specified String
in the specified Graphics
context.
Font.getStringBounds(String, FontRenderContext)
public Rectangle2D getStringBounds(String str, int beginIndex, int limit, Graphics context)
String
in the specified Graphics
context. The bounds is used to layout the String
.
str
- the specified String
beginIndex
- the offset of the beginning of str
limit
- the length of str
context
- the specified Graphics
context
Rectangle2D
that is the bounding box of the specified String
in the specified Graphics
context.
Font.getStringBounds(String, int, int, FontRenderContext)
public Rectangle2D getStringBounds(char[] chars, int beginIndex, int limit, Graphics context)
Graphics
context. The bounds is used to layout the String
created with the specified array of characters, beginIndex
and limit
.
chars
- an array of characters
beginIndex
- the initial offset of the array of characters
limit
- the length of the array of characters
context
- the specified Graphics
context
Rectangle2D
that is the bounding box of the specified character array in the specified Graphics
context.
Font.getStringBounds(char[], int, int, FontRenderContext)
public Rectangle2D getStringBounds(CharacterIterator ci, int beginIndex, int limit, Graphics context)
CharacterIterator
in the specified Graphics
context.
ci
- the specified CharacterIterator
beginIndex
- the initial offset in ci
limit
- the end index of ci
context
- the specified Graphics
context
Rectangle2D
that is the bounding box of the characters indexed in the specified CharacterIterator
in the specified Graphics
context.
Font.getStringBounds(CharacterIterator, int, int, FontRenderContext)
public Rectangle2D getMaxCharBounds(Graphics context)
Graphics
context.
context
- the specified Graphics
context
Rectangle2D
that is the bounding box for the character with the maximum bounds.
Font.getMaxCharBounds(FontRenderContext)
public String toString()
FontMetrics
object's values as a String
.
toString
in class Object
String
representation of this FontMetrics
object.
Copyright © 2004, 2010 Oracle and/or its affiliates. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.
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