javax.swing.text
Class Utilities

java.lang.Object
  extended by javax.swing.text.Utilities

public class Utilities
extends Object

A set of utilities to deal with text. This is used by several other classes inside this package.


Constructor Summary
Utilities()
          Creates a new Utilities object.
 
Method Summary
static int drawTabbedText(Segment s, int x, int y, Graphics g, TabExpander e, int startOffset)
          Draws the given text segment.
static int getBreakLocation(Segment s, FontMetrics metrics, int x0, int x, TabExpander e, int startOffset)
          Determine where to break the text in the given Segment, attempting to find a word boundary.
static int getNextWord(JTextComponent c, int offs)
          Finds the start of the next word for the given offset.
static Element getParagraphElement(JTextComponent c, int offset)
          Returns the paragraph element in the text component c at the specified location offset.
static int getPositionAbove(JTextComponent c, int offset, int x)
          Returns the document position that is closest above to the specified x coordinate in the row containing offset.
static int getPositionBelow(JTextComponent c, int offset, int x)
          Returns the document position that is closest below to the specified x coordinate in the row containing offset.
static int getPreviousWord(JTextComponent c, int offs)
          Finds the start of the previous word for the given offset.
static int getRowEnd(JTextComponent c, int offs)
          Get the model position of the end of the row that contains the specified model position.
static int getRowStart(JTextComponent c, int offs)
          Get the model position of the start of the row that contains the specified model position.
static int getTabbedTextOffset(Segment s, FontMetrics fm, int x0, int x, TabExpander te, int p0)
          Provides a facility to map screen coordinates into a model location.
static int getTabbedTextOffset(Segment s, FontMetrics fm, int x0, int x, TabExpander te, int p0, boolean round)
          Provides a facility to map screen coordinates into a model location.
static int getTabbedTextWidth(Segment s, FontMetrics metrics, int x, TabExpander e, int startOffset)
          Determines the width, that the given text s would take if it was printed with the given FontMetrics on the specified screen position.
static int getWordEnd(JTextComponent c, int offs)
          Finds the end of a word for the given location.
static int getWordStart(JTextComponent c, int offs)
          Finds the start of a word for the given location.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

Utilities

public Utilities()
Creates a new Utilities object.

Method Detail

drawTabbedText

public static final int drawTabbedText(Segment s,
                                       int x,
                                       int y,
                                       Graphics g,
                                       TabExpander e,
                                       int startOffset)
Draws the given text segment. Contained tabs and newline characters are taken into account. Tabs are expanded using the specified TabExpander. The X and Y coordinates denote the start of the baseline where the text should be drawn.

Parameters:
s - the text fragment to be drawn.
x - the x position for drawing.
y - the y position for drawing.
g - the Graphics context for drawing.
e - the TabExpander which specifies the Tab-expanding technique.
startOffset - starting offset in the text.
Returns:
the x coordinate at the end of the drawn text.

getTabbedTextWidth

public static final int getTabbedTextWidth(Segment s,
                                           FontMetrics metrics,
                                           int x,
                                           TabExpander e,
                                           int startOffset)
Determines the width, that the given text s would take if it was printed with the given FontMetrics on the specified screen position.

Parameters:
s - the text fragment
metrics - the font metrics of the font to be used
x - the x coordinate of the point at which drawing should be done
e - the TabExpander to be used
startOffset - the index in s where to start

getTabbedTextOffset

public static final int getTabbedTextOffset(Segment s,
                                            FontMetrics fm,
                                            int x0,
                                            int x,
                                            TabExpander te,
                                            int p0,
                                            boolean round)
Provides a facility to map screen coordinates into a model location. For a given text fragment and start location within this fragment, this method determines the model location so that the resulting fragment fits best into the span [x0, x]. The parameter round controls which model location is returned if the view coordinates are on a character: If round is true, then the result is rounded up to the next character, so that the resulting fragment is the smallest fragment that is larger than the specified span. If round is false, then the resulting fragment is the largest fragment that is smaller than the specified span.

Parameters:
s - the text segment
fm - the font metrics to use
x0 - the starting screen location
x - the target screen location at which the requested fragment should end
te - the tab expander to use; if this is null, TABs are expanded to one space character
p0 - the starting model location
round - if true round up to the next location, otherwise round down to the current location
Returns:
the model location, so that the resulting fragment fits within the specified span

getTabbedTextOffset

public static final int getTabbedTextOffset(Segment s,
                                            FontMetrics fm,
                                            int x0,
                                            int x,
                                            TabExpander te,
                                            int p0)
Provides a facility to map screen coordinates into a model location. For a given text fragment and start location within this fragment, this method determines the model location so that the resulting fragment fits best into the span [x0, x]. This method rounds up to the next location, so that the resulting fragment will be the smallest fragment of the text, that is greater than the specified span.

Parameters:
s - the text segment
fm - the font metrics to use
x0 - the starting screen location
x - the target screen location at which the requested fragment should end
te - the tab expander to use; if this is null, TABs are expanded to one space character
p0 - the starting model location
Returns:
the model location, so that the resulting fragment fits within the specified span

getNextWord

public static final int getNextWord(JTextComponent c,
                                    int offs)
                             throws BadLocationException
Finds the start of the next word for the given offset.

Parameters:
c - the text component
offs - the offset in the document
Returns:
the location in the model of the start of the next word.
Throws:
BadLocationException - if the offset is invalid.

getPreviousWord

public static final int getPreviousWord(JTextComponent c,
                                        int offs)
                                 throws BadLocationException
Finds the start of the previous word for the given offset.

Parameters:
c - the text component
offs - the offset in the document
Returns:
the location in the model of the start of the previous word.
Throws:
BadLocationException - if the offset is invalid.

getWordStart

public static final int getWordStart(JTextComponent c,
                                     int offs)
                              throws BadLocationException
Finds the start of a word for the given location.

Parameters:
c - the text component
offs - the offset location
Returns:
the location of the word beginning
Throws:
BadLocationException - if the offset location is invalid

getWordEnd

public static final int getWordEnd(JTextComponent c,
                                   int offs)
                            throws BadLocationException
Finds the end of a word for the given location.

Parameters:
c - the text component
offs - the offset location
Returns:
the location of the word end
Throws:
BadLocationException - if the offset location is invalid

getRowEnd

public static final int getRowEnd(JTextComponent c,
                                  int offs)
                           throws BadLocationException
Get the model position of the end of the row that contains the specified model position. Return null if the given JTextComponent does not have a size.

Parameters:
c - the JTextComponent
offs - the model position
Returns:
the model position of the end of the row containing the given offset
Throws:
BadLocationException - if the offset is invalid

getRowStart

public static final int getRowStart(JTextComponent c,
                                    int offs)
                             throws BadLocationException
Get the model position of the start of the row that contains the specified model position. Return null if the given JTextComponent does not have a size.

Parameters:
c - the JTextComponent
offs - the model position
Returns:
the model position of the start of the row containing the given offset
Throws:
BadLocationException - if the offset is invalid

getBreakLocation

public static final int getBreakLocation(Segment s,
                                         FontMetrics metrics,
                                         int x0,
                                         int x,
                                         TabExpander e,
                                         int startOffset)
Determine where to break the text in the given Segment, attempting to find a word boundary.

Parameters:
s - the Segment that holds the text
metrics - the font metrics used for calculating the break point
x0 - starting view location representing the start of the text
x - the target view location
e - the TabExpander used for expanding tabs (if this is null tabs are expanded to 1 space)
startOffset - the offset in the Document of the start of the text
Returns:
the offset at which we should break the text

getParagraphElement

public static final Element getParagraphElement(JTextComponent c,
                                                int offset)
Returns the paragraph element in the text component c at the specified location offset.

Parameters:
c - the text component
offset - the offset of the paragraph element to return
Returns:
the paragraph element at offset

getPositionAbove

public static final int getPositionAbove(JTextComponent c,
                                         int offset,
                                         int x)
                                  throws BadLocationException
Returns the document position that is closest above to the specified x coordinate in the row containing offset.

Parameters:
c - the text component
offset - the offset
x - the x coordinate
Returns:
the document position that is closest above to the specified x coordinate in the row containing offset
Throws:
BadLocationException - if offset is not a valid offset

getPositionBelow

public static final int getPositionBelow(JTextComponent c,
                                         int offset,
                                         int x)
                                  throws BadLocationException
Returns the document position that is closest below to the specified x coordinate in the row containing offset.

Parameters:
c - the text component
offset - the offset
x - the x coordinate
Returns:
the document position that is closest above to the specified x coordinate in the row containing offset
Throws:
BadLocationException - if offset is not a valid offset