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Class java.awt.swing.text.ParagraphView

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

public class ParagraphView
extends BoxView
implements TabExpander
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.

See Also:
View

Fields inherited from class java.awt.swing.text.View
 BadBreakWeight, ExcellentBreakWeight, ForcedBreakWeight, GoodBreakWeight, X_AXIS, Y_AXIS
 

Constructor Summary
 ParagraphView(Element elem)
Constructs a ParagraphView for the given element.
 

Method Summary
void  adjustRow(java.awt.swing.text.ParagraphView.Row r, int desiredSpan)
Adjust the given row if possible to fit within the layout span.
View  breakView(int axis, float len, Shape a)
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.

void  changedUpdate(DocumentEvent changes, Shape a, ViewFactory f)
Gives notification from the document that attributes were changed in a location that this view is responsible for.
int  findOffsetToCharactersInString(char[] string, int start)
Finds the next character in the document with a character in string, starting at offset start.
float  getAlignment(int axis)
Determines the desired alignment for this view along an axis.
int  getBreakWeight(int axis, float len)
ParagraphView instances are breakable along the Y_AXIS only, and only if len is after the first row.
float  getPartialSize(int startOffset, int endOffset)
Returns the size used by the views between startOffset and endOffset.
float  getPreferredSpan(int axis)
Determines the preferred span for this view along an axis.
int  getResizeWeight(int axis)
Gets the resize weight.
View  getViewAtPosition(int pos, Rectangle a)
Fetches the child view that represents the given position in the model.
void  insertUpdate(DocumentEvent changes, Shape a, ViewFactory f)
Gives notification that something was inserted into the document in a location that this view is responsible for.
void  layout(int width, int height)
Lays out the children.
void  loadChildren(ViewFactory f)
Loads all of the children to initialize the view.
float  nextTabStop(float x, int tabOffset)
Returns the next tab stop position given a reference position.
void  paint(Graphics g, Shape a)
Renders using the given rendering surface and area on that surface.
void  removeUpdate(DocumentEvent changes, Shape a, ViewFactory f)
Gives notification that something was removed from the document in a location that this view is responsible for.
 
Methods inherited from class java.awt.swing.text.BoxView
 changedUpdate, childAllocation, getAlignment, getPreferredSpan, getResizeWeight, getViewAtPoint, insertUpdate, isAfter, isAllocationValid, isBefore, layout, modelToView, paint, paintChild, preferenceChanged, removeUpdate, replace, setSize, viewToModel
 
Methods inherited from class java.awt.swing.text.CompositeView
 append, childAllocation, getBottomInset, getChildAllocation, getInsideAllocation, getLeftInset, getRightInset, getTopInset, getView, getViewAtPoint, getViewAtPosition, getViewCount, insert, isAfter, isBefore, loadChildren, modelToView, removeAll, replace, setInsets, setParagraphInsets, setParent, viewToModel
 
Methods inherited from class java.awt.swing.text.View
 breakView, changedUpdate, createFragment, getAlignment, getBreakWeight, getChildAllocation, getContainer, getDocument, getElement, getEndOffset, getParent, getPreferredSpan, getResizeWeight, getStartOffset, getView, getViewCount, getViewFactory, insertUpdate, modelToView, paint, preferenceChanged, removeUpdate, setParent, setSize, viewToModel
 
Methods inherited from class java.lang.Object
 clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

ParagraphView

public ParagraphView(Element elem)
Constructs a ParagraphView for the given element.
Parameters:
elem - the element that this view is responsible for
Method Detail

loadChildren

protected void loadChildren(ViewFactory f)
Loads all of the children to initialize the view. This is called by the setParent method. This is reimplemented to not load any children directly (as they are created in the process of formatting). This does create views to represent the child elements, but they are placed into a pool that is used in the process of formatting.
Parameters:
f - the view factory
Overrides:
loadChildren in class CompositeView

getViewAtPosition

protected View getViewAtPosition(int pos,
                                 Rectangle a)
Fetches the child view that represents the given position in the model. This is implemented to walk through the children looking for a range that contains the given position. In this view the children do not have a one to one mapping with the child elements (ie. the children are actually rows that represent a portion of the element this view represents).
Parameters:
pos - the search position
a - the allocation to the box on entry, and the allocation of the view containing the position on exit
Overrides:
getViewAtPosition in class CompositeView

layout

protected void layout(int width,
                      int height)
Lays out the children. If the layout span has changed, the rows are rebuilt. The superclass functionality is called after checking and possibly rebuilding the rows. If the height has changed, the preferenceChanged method is called on the parent since the vertical preference is rigid.
Parameters:
width - the width to lay out against. This is the width inside of the inset area.
height - the height to lay out against (not used by paragraph, but used by the superclass). This is the height inside of the inset area.
Overrides:
layout in class BoxView

adjustRow

protected void adjustRow(java.awt.swing.text.ParagraphView.Row r,
                         int desiredSpan)
Adjust 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.
Parameters:
r - the row to adjust to the current layout span.
desiredSpan - the current layout span

nextTabStop

public float nextTabStop(float x,
                         int tabOffset)
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 it's 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, it's 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).

Implements:
nextTabStop in interface TabExpander
Parameters:
x - the position
tabOffset - the position within the text stream that the tab occurred at.
Returns:
the trailing end of the tab expansion
See Also:
TabSet, TabStop, LabelView

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.

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.

paint

public void paint(Graphics g,
                  Shape a)
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.
Parameters:
g - the rendering surface to use
a - the allocated region to render into
Overrides:
paint in class BoxView
See Also:
paint

getPreferredSpan

public float getPreferredSpan(int axis)
Determines the preferred span for this view along an axis. For the paragraph it's whatever it was formatted to along the x axis and whatever the box calculation is for the y axis.
Parameters:
axis - may be either X_AXIS or Y_AXIS
Throws:
IllegalArgumentException - for an invalid axis
Overrides:
getPreferredSpan in class BoxView

getAlignment

public float getAlignment(int axis)
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.
Parameters:
axis - may be either X_AXIS or Y_AXIS
Overrides:
getAlignment in class BoxView

getResizeWeight

public int getResizeWeight(int axis)
Gets the resize weight. A value of 0 or less is not resizable.
Parameters:
axis - may be either X_AXIS or Y_AXIS
Returns:
the weight
Throws:
IllegalArgumentException - for an invalid axis
Overrides:
getResizeWeight in class BoxView

breakView

public View breakView(int axis,
                      float len,
                      Shape a)
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 X_AXIS or Y_AXIS
len - specifies where a potential break is desired along the given axis
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:
breakView

getBreakWeight

public int getBreakWeight(int axis,
                          float len)
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 X_AXIS or Y_AXIS
len - specifies where a potential break is desired
Returns:
a value indicating the attractiveness of breaking here
See Also:
getBreakWeight

insertUpdate

public void insertUpdate(DocumentEvent changes,
                         Shape a,
                         ViewFactory f)
Gives notification that something was inserted into the document in a location that this view is responsible for.
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
Overrides:
insertUpdate in class BoxView
See Also:
insertUpdate

removeUpdate

public void removeUpdate(DocumentEvent changes,
                         Shape a,
                         ViewFactory f)
Gives notification that something was removed from the document in a location that this view is responsible for.
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
Overrides:
removeUpdate in class BoxView
See Also:
removeUpdate

changedUpdate

public void changedUpdate(DocumentEvent changes,
                          Shape a,
                          ViewFactory f)
Gives notification from the document that attributes were changed in a location that this view is responsible for.
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
Overrides:
changedUpdate in class BoxView
See Also:
changedUpdate

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