javax.swing.text
Class ParagraphView

java.lang.Object
  |
  +--javax.swing.text.View
        |
        +--javax.swing.text.CompositeView
              |
              +--javax.swing.text.BoxView
                    |
                    +--javax.swing.text.FlowView
                          |
                          +--javax.swing.text.ParagraphView

All Implemented Interfaces:

SwingConstants, TabExpander

Direct Known Subclasses:

javax.swing.JEditorPane.PlainEditorKit.PlainParagraph

public class ParagraphView

extends FlowView

implements TabExpander

Safe: View of a simple line-wrapping paragraph that supports multiple fonts, colors, components, icons, etc. It is basically a vertical box with a margin around it. The contents of the box are a bunch of rows which are special horizontal boxes. This view creates a collection of views that represent the child elements of the paragraph element. Each of these views are placed into a row directly if they will fit, otherwise the breakView method is called to try and carve the view into pieces that fit.

Version:

1.86 02/13/02

Author:

Timothy Prinzing, Scott Violet

See Also:

View

Field Summary

protected int	firstLineIndent Indentation for the first line, from the left inset.
(package private) static Class	i18nStrategy Used to create an i18n-based layout strategy
private int	justification
private float	lineSpacing
private int	tabBase Used by the TabExpander functionality to determine where to base the tab calculations.
(package private) static char[]	tabChars Used for searching for a tab.
(package private) static char[]	tabDecimalChars Used for searching for a tab or decimal character.

Fields inherited from class javax.swing.text.FlowView

layoutPool, layoutSpan, strategy

Fields inherited from class javax.swing.text.BoxView

majorAllocValid, majorAxis, majorOffsets, majorRequest, majorReqValid, majorSpan, majorSpans, minorAllocValid, minorOffsets, minorRequest, minorReqValid, minorSpan, minorSpans, tempRect

Fields inherited from class javax.swing.text.CompositeView

Fields inherited from class javax.swing.text.View

BadBreakWeight, ExcellentBreakWeight, ForcedBreakWeight, GoodBreakWeight, sharedBiasReturn, X_AXIS, Y_AXIS

Fields inherited from interface javax.swing.SwingConstants

BOTTOM, CENTER, EAST, HORIZONTAL, LEADING, LEFT, NEXT, NORTH, NORTH_EAST, NORTH_WEST, PREVIOUS, RIGHT, SOUTH, SOUTH_EAST, SOUTH_WEST, TOP, TRAILING, VERTICAL, WEST

Constructor Summary

ParagraphView(Element elem)
Enabled: Constructs a ParagraphView for the given element.

Method Summary

protected void	adjustRow(javax.swing.text.ParagraphView.Row r, int desiredSpan, int x) Adjusts the given row if possible to fit within the layout span.
View	breakView(int axis, float len, Shape a) Enabled: Breaks this view on the given axis at the given length.
void	changedUpdate(DocumentEvent changes, Shape a, ViewFactory f) Suppressed: Gives notification from the document that attributes were changed in a location that this view is responsible for.
protected View	createRow() Create a View that should be used to hold a a row's worth of children in a flow.
protected int	findOffsetToCharactersInString(char[] string, int start) Finds the next character in the document with a character in string, starting at offset start.
protected boolean	flipEastAndWestAtEnds(int position, javax.swing.text.Position.Bias bias) Determines in which direction the next view lays.
float	getAlignment(int axis) Enabled: Determines the desired alignment for this view along an axis.
int	getBreakWeight(int axis, float len) Enabled: Gets the break weight for a given location.
protected int	getClosestPositionTo(int pos, javax.swing.text.Position.Bias b, Shape a, int direction, javax.swing.text.Position.Bias[] biasRet, int rowIndex, int x) Returns the closest model position to x.
int	getFlowSpan(int index) Enabled: Fetches the constraining span to flow against for the given child index.
int	getFlowStart(int index) Enabled: Fetches the location along the flow axis that the flow span will start at.
protected View	getLayoutView(int index) Returns the view at a given index.
protected int	getLayoutViewCount() Returns the number of views that this view is responsible for.
protected int	getNextNorthSouthVisualPositionFrom(int pos, javax.swing.text.Position.Bias b, Shape a, int direction, javax.swing.text.Position.Bias[] biasRet) Returns the next visual position for the cursor, in either the east or west direction.
protected float	getPartialSize(int startOffset, int endOffset) Returns the size used by the views between startOffset and endOffset.
protected float	getTabBase() Returns where the tabs are calculated from.
protected TabSet	getTabSet() Gets the Tabset to be used in calculating tabs.
float	nextTabStop(float x, int tabOffset) Enabled: Returns the next tab stop position given a reference position.
void	paint(Graphics g, Shape a) Suppressed: Renders using the given rendering surface and area on that surface.
protected void	setFirstLineIndent(float fi) Sets the indent on the first line.
protected void	setJustification(int j) Sets the type of justification.
protected void	setLineSpacing(float ls) Sets the line spacing.
protected void	setPropertiesFromAttributes() Set the cached properties from the attributes.

Methods inherited from class javax.swing.text.FlowView

calculateMinorAxisRequirements, getFlowAxis, getViewIndexAtPosition, insertUpdate, layout, loadChildren, removeUpdate

Methods inherited from class javax.swing.text.BoxView

baselineLayout, baselineRequirements, calculateMajorAxisRequirements, checkRequests, childAllocation, forwardUpdate, getAxis, getChildAllocation, getHeight, getMaximumSpan, getMinimumSpan, getOffset, getPreferredSpan, getResizeWeight, getSpan, getSpanOnAxis, getViewAtPoint, getWidth, isAfter, isAllocationValid, isBefore, isLayoutValid, layoutChanged, layoutMajorAxis, layoutMinorAxis, modelToView, paintChild, preferenceChanged, replace, setAxis, setSize, setSpanOnAxis, updateChildSizes, updateLayoutArray, viewToModel

Methods inherited from class javax.swing.text.CompositeView

getBottomInset, getInsideAllocation, getLeftInset, getNextEastWestVisualPositionFrom, getNextVisualPositionFrom, getRightInset, getTopInset, getView, getViewAtPosition, getViewCount, getViewIndex, modelToView, setInsets, setParagraphInsets, setParent

Methods inherited from class javax.swing.text.View

append, breakView, createFragment, forwardUpdateToView, getAttributes, getBreakWeight, getContainer, getDocument, getElement, getEndOffset, getGraphics, getParent, getStartOffset, getToolTipText, getViewFactory, getViewIndex, insert, isVisible, modelToView, remove, removeAll, updateChildren, updateLayout, viewToModel

Methods inherited from class java.lang.Object

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

Field Detail

justification

private int justification

lineSpacing

private float lineSpacing

firstLineIndent

protected int firstLineIndent

Indentation for the first line, from the left inset.

tabBase

private int tabBase

Used by the TabExpander functionality to determine where to base the tab calculations. This is basically the location of the left side of the paragraph.

i18nStrategy

static Class i18nStrategy

Used to create an i18n-based layout strategy

tabChars

static char[] tabChars

Used for searching for a tab.

tabDecimalChars

static char[] tabDecimalChars

Used for searching for a tab or decimal character.

Constructor Detail

ParagraphView

public ParagraphView(Element elem)

Enabled: Constructs a ParagraphView for the given element.

Parameters:

elem - the element that this view is responsible for

Method Detail

setJustification

protected void setJustification(int j)

Sets the type of justification.

Parameters:

j - one of the following values:

• StyleConstants.ALIGN_LEFT
• StyleConstants.ALIGN_CENTER
• StyleConstants.ALIGN_RIGHT

setLineSpacing

protected void setLineSpacing(float ls)

Sets the line spacing.

Parameters:

ls - the value is a factor of the line hight

setFirstLineIndent

protected void setFirstLineIndent(float fi)

Sets the indent on the first line.

Parameters:

fi - the value in points

setPropertiesFromAttributes

protected void setPropertiesFromAttributes()

Set the cached properties from the attributes.

getLayoutViewCount

protected int getLayoutViewCount()

Returns the number of views that this view is responsible for. The child views of the paragraph are rows which have been used to arrange pieces of the Views that represent the child elements. This is the number of views that have been tiled in two dimensions, and should be equivalent to the number of child elements to the element this view is responsible for.

Returns:

the number of views that this ParagraphView is responsible for

getLayoutView

protected View getLayoutView(int index)

Returns the view at a given index. The child views of the paragraph are rows which have been used to arrange pieces of the Views that represent the child elements. This methods returns the view responsible for the child element index (prior to breaking). These are the Views that were produced from a factory (to represent the child elements) and used for layout.

Parameters:

index - the index of the desired view

Returns:

the view at index

adjustRow

protected void adjustRow(javax.swing.text.ParagraphView.Row r,
                         int desiredSpan,
                         int x)

Adjusts the given row if possible to fit within the layout span. By default this will try to find the highest break weight possible nearest the end of the row. If a forced break is encountered, the break will be positioned there.

This is meant for internal usage, and should not be used directly.

Parameters:

r - the row to adjust to the current layout span

desiredSpan - the current layout span >= 0

x - the location r starts at

getNextNorthSouthVisualPositionFrom

protected int getNextNorthSouthVisualPositionFrom(int pos,
                                                  javax.swing.text.Position.Bias b,
                                                  Shape a,
                                                  int direction,
                                                  javax.swing.text.Position.Bias[] biasRet)
                                           throws BadLocationException

Returns the next visual position for the cursor, in either the east or west direction. Overridden from CompositeView.

Overrides:

getNextNorthSouthVisualPositionFrom in class CompositeView

Parameters:

pos - position into the model

a - the allocated region to render into

direction - either SwingConstants.NORTH or SwingConstants.SOUTH

biasRet - an array containing the bias that were checked in this method

b - a bias value of either Position.Bias.Forward or Position.Bias.Backward

Returns:

the location in the model that represents the next location visual position

BadLocationException

See Also:

CompositeView.getNextVisualPositionFrom(int, javax.swing.text.Position.Bias, java.awt.Shape, int, javax.swing.text.Position.Bias[])

getClosestPositionTo

protected int getClosestPositionTo(int pos,
                                   javax.swing.text.Position.Bias b,
                                   Shape a,
                                   int direction,
                                   javax.swing.text.Position.Bias[] biasRet,
                                   int rowIndex,
                                   int x)
                            throws BadLocationException

Returns the closest model position to x. rowIndex gives the index of the view that corresponds that should be looked in.

Parameters:

pos - position into the model

a - the allocated region to render into

direction - one of the following values:

• SwingConstants.NORTH
• SwingConstants.SOUTH

biasRet - an array containing the bias that were checked in this method

rowIndex - the index of the view

x - the x coordinate of interest

Returns:

the closest model position to x

BadLocationException

flipEastAndWestAtEnds

protected boolean flipEastAndWestAtEnds(int position,
                                        javax.swing.text.Position.Bias bias)

Determines in which direction the next view lays. Consider the View at index n. Typically the Views are layed out from left to right, so that the View to the EAST will be at index n + 1, and the View to the WEST will be at index n - 1. In certain situations, such as with bidirectional text, it is possible that the View to EAST is not at index n + 1, but rather at index n - 1, or that the View to the WEST is not at index n - 1, but index n + 1. In this case this method would return true, indicating the Views are layed out in descending order.

This will return true if the text is layed out right to left at position, otherwise false.

Overrides:

flipEastAndWestAtEnds in class BoxView

Parameters:

position - position into the model

bias - either Position.Bias.Forward or Position.Bias.Backward

Returns:

true if the text is layed out right to left at position, otherwise false.

getFlowSpan

public int getFlowSpan(int index)

Enabled: Fetches the constraining span to flow against for the given child index.

Overrides:

getFlowSpan in class FlowView

Parameters:

index - the index of the view being queried

Returns:

the constraining span for the given view at index

See Also:

FlowView.getFlowStart(int)

getFlowStart

public int getFlowStart(int index)

Enabled: Fetches the location along the flow axis that the flow span will start at.

Overrides:

getFlowStart in class FlowView

Parameters:

index - the index of the view being queried

Returns:

the location for the given view at index

See Also:

FlowView.getFlowSpan(int)

createRow

protected View createRow()

Create a View that should be used to hold a a row's worth of children in a flow.

Specified by:

createRow in class FlowView

Returns:

the new View

nextTabStop

public float nextTabStop(float x,
                         int tabOffset)

Enabled: Returns the next tab stop position given a reference position. This view implements the tab coordinate system, and calls getTabbedSpan on the logical children in the process of layout to determine the desired span of the children. The logical children can delegate their tab expansion upward to the paragraph which knows how to expand tabs. LabelView is an example of a view that delegates its tab expansion needs upward to the paragraph.

This is implemented to try and locate a TabSet in the paragraph element's attribute set. If one can be found, its settings will be used, otherwise a default expansion will be provided. The base location for for tab expansion is the left inset from the paragraphs most recent allocation (which is what the layout of the children is based upon).

Specified by:

nextTabStop in interface TabExpander

Parameters:

x - the X reference position

tabOffset - the position within the text stream that the tab occurred at >= 0

Returns:

the trailing end of the tab expansion >= 0

See Also:

TabSet, TabStop, LabelView

getTabSet

protected TabSet getTabSet()

Gets the Tabset to be used in calculating tabs.

Returns:

the TabSet

getPartialSize

protected float getPartialSize(int startOffset,
                               int endOffset)

Returns the size used by the views between startOffset and endOffset. This uses getPartialView to calculate the size if the child view implements the TabableView interface. If a size is needed and a View does not implement the TabableView interface, the preferredSpan will be used.

Parameters:

startOffset - the starting document offset >= 0

endOffset - the ending document offset >= startOffset

Returns:

the size >= 0

findOffsetToCharactersInString

protected int findOffsetToCharactersInString(char[] string,
                                             int start)

Finds the next character in the document with a character in string, starting at offset start. If there are no characters found, -1 will be returned.

Parameters:

string - the string of characters

start - where to start in the model >= 0

Returns:

the document offset, or -1 if no characters found

getTabBase

protected float getTabBase()

Returns where the tabs are calculated from.

Returns:

where tabs are calculated from

paint

public void paint(Graphics g,
                  Shape a)

Suppressed: Renders using the given rendering surface and area on that surface. This is implemented to delgate to the superclass after stashing the base coordinate for tab calculations.

Overrides:

paint in class BoxView

Parameters:

g - the rendering surface to use

a - the allocated region to render into

See Also:

View.paint(java.awt.Graphics, java.awt.Shape)

getAlignment

public float getAlignment(int axis)

Enabled: Determines the desired alignment for this view along an axis. This is implemented to give the alignment to the center of the first row along the y axis, and the default along the x axis.

Overrides:

getAlignment in class BoxView

Parameters:

axis - may be either View.X_AXIS or View.Y_AXIS

Returns:

the desired alignment. This should be a value between 0.0 and 1.0 inclusive, where 0 indicates alignment at the origin and 1.0 indicates alignment to the full span away from the origin. An alignment of 0.5 would be the center of the view.

breakView

public View breakView(int axis,
                      float len,
                      Shape a)

Enabled: Breaks this view on the given axis at the given length.

ParagraphView instances are breakable along the Y_AXIS only, and only if len is after the first line.

Parameters:

axis - may be either View.X_AXIS or View.Y_AXIS

len - specifies where a potential break is desired along the given axis >= 0

a - the current allocation of the view

Returns:

the fragment of the view that represents the given span, if the view can be broken; if the view doesn't support breaking behavior, the view itself is returned

See Also:

View.breakView(int, int, float, float)

getBreakWeight

public int getBreakWeight(int axis,
                          float len)

Enabled: Gets the break weight for a given location.

ParagraphView instances are breakable along the Y_AXIS only, and only if len is after the first row. If the length is less than one row, a value of BadBreakWeight is returned.

Parameters:

axis - may be either View.X_AXIS or View.Y_AXIS

len - specifies where a potential break is desired >= 0

Returns:

a value indicating the attractiveness of breaking here; either GoodBreakWeight or BadBreakWeight

See Also:

View.getBreakWeight(int, float, float)

changedUpdate

public void changedUpdate(DocumentEvent changes,
                          Shape a,
                          ViewFactory f)

Suppressed: Gives notification from the document that attributes were changed in a location that this view is responsible for.

Overrides:

changedUpdate in class FlowView

Parameters:

changes - the change information from the associated document

a - the current allocation of the view

f - the factory to use to rebuild if the view has children

See Also:

View.changedUpdate(javax.swing.event.DocumentEvent, java.awt.Shape, javax.swing.text.ViewFactory)