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java.lang.Object java.awt.font.TextMeasurer
The TextMeasurer
class provides the primitive operations
needed for line break: measuring up to a given advance, determining the
advance of a range of characters, and generating a
TextLayout
for a range of characters. It also provides
methods for incremental editing of paragraphs.
A TextMeasurer
object is constructed with an
AttributedCharacterIterator
representing a single paragraph of text. The value returned by the
getBeginIndex
method of AttributedCharacterIterator
defines the absolute index of the first character. The value
returned by the
getEndIndex
method of AttributedCharacterIterator
defines the index
past the last character. These values define the range of indexes to
use in calls to the TextMeasurer
. For example, calls to
get the advance of a range of text or the line break of a range of text
must use indexes between the beginning and end index values. Calls to
insertChar
and
deleteChar
reset the TextMeasurer
to use the beginning index and end
index of the AttributedCharacterIterator
passed in those calls.
Most clients will use the more convenient LineBreakMeasurer
,
which implements the standard line break policy (placing as many words
as will fit on each line).
LineBreakMeasurer
Field Summary | |
private CharArrayIterator |
charIter
|
private boolean |
collectStats
|
private static float |
EST_LINES
|
private byte |
fBaseline
|
private float[] |
fBaselineOffsets
|
private Bidi |
fBidi
|
private char[] |
fChars
|
private int |
fComponentLimit
|
private sun.awt.font.TextLineComponent[] |
fComponents
|
private int |
fComponentStart
|
private FontRenderContext |
fFrc
|
private boolean |
fIsDirectionLTR
|
private float |
fJustifyRatio
|
private byte[] |
fLevels
|
private BreakIterator |
fLineBreak
|
private int |
formattedChars
|
private StyledParagraph |
fParagraph
|
private int |
fStart
|
private boolean |
haveLayoutWindow
|
(package private) int |
layoutCharCount
|
(package private) int |
layoutCount
|
private static boolean |
wantStats
|
Constructor Summary | |
TextMeasurer(AttributedCharacterIterator text,
FontRenderContext frc)
Constructs a TextMeasurer from the source text.
|
Method Summary | |
private int |
calcLineBreak(int pos,
float maxAdvance)
|
protected Object |
clone()
Creates and returns a copy of this object. |
void |
deleteChar(AttributedCharacterIterator newParagraph,
int deletePos)
Updates the TextMeasurer after a single character has
been deleted
from the paragraph currently represented by this
TextMeasurer . |
private void |
ensureComponents(int start,
int limit)
|
private void |
generateComponents(int startingAt,
int endingAt)
Generate components for the paragraph. |
float |
getAdvanceBetween(int start,
int limit)
Returns the graphical width of a line beginning at start
and including characters up to limit .
|
(package private) char[] |
getChars()
NOTE: This method is only for LineBreakMeasurer's use. |
TextLayout |
getLayout(int start,
int limit)
Returns a TextLayout on the given character range. |
int |
getLineBreakIndex(int start,
float maxAdvance)
Returns the index of the first character which will not fit on on a line beginning at start and possible
measuring up to maxAdvance in graphical width. |
private void |
initAll(AttributedCharacterIterator text)
Initialize state, including fChars array, direction, and fBidi. |
void |
insertChar(AttributedCharacterIterator newParagraph,
int insertPos)
Updates the TextMeasurer after a single character has
been inserted
into the paragraph currently represented by this
TextMeasurer . |
private void |
invalidateComponents()
|
private sun.awt.font.TextLineComponent[] |
makeComponentsOnRange(int startPos,
int limitPos)
|
private void |
makeLayoutWindow(int localStart)
|
private TextLine |
makeTextLineOnRange(int startPos,
int limitPos)
|
private void |
printStats()
|
private int |
trailingCdWhitespaceStart(int startPos,
int limitPos)
According to the Unicode Bidirectional Behavior specification (Unicode Standard 2.0, section 3.11), whitespace at the ends of lines which would naturally flow against the base direction must be made to flow with the line direction, and moved to the end of the line. |
Methods inherited from class java.lang.Object |
equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Field Detail |
private static float EST_LINES
private FontRenderContext fFrc
private int fStart
private char[] fChars
private Bidi fBidi
private byte[] fLevels
private sun.awt.font.TextLineComponent[] fComponents
private int fComponentStart
private int fComponentLimit
private boolean haveLayoutWindow
private BreakIterator fLineBreak
private CharArrayIterator charIter
int layoutCount
int layoutCharCount
private StyledParagraph fParagraph
private boolean fIsDirectionLTR
private byte fBaseline
private float[] fBaselineOffsets
private float fJustifyRatio
private int formattedChars
private static boolean wantStats
private boolean collectStats
Constructor Detail |
public TextMeasurer(AttributedCharacterIterator text, FontRenderContext frc)
TextMeasurer
from the source text.
The source text should be a single entire paragraph.
text
- the source paragraph. Cannot be null.frc
- the information about a graphics device which is needed
to measure the text correctly. Cannot be null.Method Detail |
protected Object clone()
Object
will be true, and that the expression:x.clone() != x
will be true, but these are not absolute requirements. While it is typically the case that:x.clone().getClass() == x.getClass()
will be true, this is not an absolute requirement.x.clone().equals(x)
By convention, the returned object should be obtained by calling super.clone. If a class and all of its superclasses (except Object) obey this convention, it will be the case that x.clone().getClass() == x.getClass().
By convention, the object returned by this method should be independent of this object (which is being cloned). To achieve this independence, it may be necessary to modify one or more fields of the object returned by super.clone before returning it. Typically, this means copying any mutable objects that comprise the internal "deep structure" of the object being cloned and replacing the references to these objects with references to the copies. If a class contains only primitive fields or references to immutable objects, then it is usually the case that no fields in the object returned by super.clone need to be modified.
The method clone for class Object performs a specific cloning operation. First, if the class of this object does not implement the interface Cloneable, then a CloneNotSupportedException is thrown. Note that all arrays are considered to implement the interface Cloneable. Otherwise, this method creates a new instance of the class of this object and initializes all its fields with exactly the contents of the corresponding fields of this object, as if by assignment; the contents of the fields are not themselves cloned. Thus, this method performs a "shallow copy" of this object, not a "deep copy" operation.
The class Object does not itself implement the interface Cloneable, so calling the clone method on an object whose class is Object will result in throwing an exception at run time.
clone
in class Object
Cloneable
private void invalidateComponents()
private void initAll(AttributedCharacterIterator text)
private void generateComponents(int startingAt, int endingAt)
private int calcLineBreak(int pos, float maxAdvance)
private int trailingCdWhitespaceStart(int startPos, int limitPos)
private sun.awt.font.TextLineComponent[] makeComponentsOnRange(int startPos, int limitPos)
private TextLine makeTextLineOnRange(int startPos, int limitPos)
private void ensureComponents(int start, int limit)
private void makeLayoutWindow(int localStart)
public int getLineBreakIndex(int start, float maxAdvance)
start
and possible
measuring up to maxAdvance
in graphical width.
start
- the character index at which to start measuring.
start
is an absolute index, not relative to the
start of the paragraphmaxAdvance
- the graphical width in which the line must fit
start
, which is not longer
than maxAdvance
in graphical width
IllegalArgumentException
- if start
is
less than the beginning of the paragraph.public float getAdvanceBetween(int start, int limit)
start
and including characters up to limit
.
start
and limit
are absolute indices,
not relative to the start of the paragraph.
start
- the character index at which to start measuringlimit
- the character index at which to stop measuring
start
and including characters up to limit
IndexOutOfBoundsException
- if limit
is less
than start
IllegalArgumentException
- if start
or
limit
is not between the beginning of
the paragraph and the end of the paragraph.public TextLayout getLayout(int start, int limit)
TextLayout
on the given character range.
start
- the index of the first characterlimit
- the index after the last character. Must be greater
than start
TextLayout
for the characters beginning at
start
up to (but not including) limit
IndexOutOfBoundsException
- if limit
is less
than start
IllegalArgumentException
- if start
or
limit
is not between the beginning of
the paragraph and the end of the paragraph.private void printStats()
public void insertChar(AttributedCharacterIterator newParagraph, int insertPos)
TextMeasurer
after a single character has
been inserted
into the paragraph currently represented by this
TextMeasurer
. After this call, this
TextMeasurer
is equivalent to a new
TextMeasurer
created from the text; however, it will
usually be more efficient to update an existing
TextMeasurer
than to create a new one from scratch.
newParagraph
- the text of the paragraph after performing
the insertion. Cannot be null.insertPos
- the position in the text where the character was
inserted. Must not be less than the start of
newParagraph
, and must be less than the end of
newParagraph
.
IndexOutOfBoundsException
- if insertPos
is less
than the start of newParagraph
or greater than
or equal to the end of newParagraph
NullPointerException
- if newParagraph
is
null
public void deleteChar(AttributedCharacterIterator newParagraph, int deletePos)
TextMeasurer
after a single character has
been deleted
from the paragraph currently represented by this
TextMeasurer
. After this call, this
TextMeasurer
is equivalent to a new TextMeasurer
created from the text; however, it will usually be more efficient
to update an existing TextMeasurer
than to create a new one
from scratch.
newParagraph
- the text of the paragraph after performing
the deletion. Cannot be null.deletePos
- the position in the text where the character was removed.
Must not be less than
the start of newParagraph
, and must not be greater than the
end of newParagraph
.
IndexOutOfBoundsException
- if deletePos
is
less than the start of newParagraph
or greater
than the end of newParagraph
NullPointerException
- if newParagraph
is
null
char[] getChars()
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