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# Class xv.xv_LabelView

    java.lang.Object
       |
       +----com.sun.java.swing.text.View
               |
               +----xv.xv_LabelView

public class xv_LabelView
extends View
implements TabableView

A xv_LabelView is a styled chunk of text that represents a view mapped over an element in the text model. The view supports breaking for the purpose of formatting. The fragments produced by breaking share the view that has primary responsibility for the element (i.e. they are nested classes and carry only a small amount of state of their own) so they can share its resources.

This view is generally responsible for displaying character level attributes in some way. Since this view represents text that may have tabs embedded in it, it implements the `TabableView` interface. Tabs will only be expanded if this view is embedded in a container that does tab expansion. ParagraphView is an example of a container that does tab expansion.

##

xv_LabelView(Element)
  Constructs a new view wrapped on an element.

##

breakView(int, int, float, float)
  Breaks this view on the given axis at the given length.
changedUpdate(DocumentEvent, Shape, ViewFactory)
  Gives notification from the document that attributes were changed in a location that this view is responsible for.
createFragment(int, int)
  Creates a view that represents a portion of the element.
getAlignment(int)
  Determines the desired alignment for this view along an axis.
getBreakWeight(int, float, float)
  Determines how attractive a break opportunity in this view is.
getPartialSpan(int, int)
  Determines the span along the same axis as tab expansion for a portion of the view.
getPreferredSpan(int)
  Determines the preferred span for this view along an axis.
getTabbedSpan(float, TabExpander)
  Determines the desired span when using the given tab expansion implementation.
modelToView(int, Shape)
  Provides a mapping from the document model coordinate space to the coordinate space of the view mapped to it.
paint(Graphics, Shape)
  Renders a portion of a text style run.
viewToModel(float, float, Shape)
  Provides a mapping from the view coordinate space to the logical coordinate space of the model.

##

xv_LabelView

     public xv_LabelView(Element elem)

  Constructs a new view wrapped on an element.

  Parameters:
    elem - the element

##

getTabbedSpan

     public float getTabbedSpan(float x,
                                TabExpander e)

  Determines the desired span when using the given tab expansion implementation.

  Parameters:
    x - the position the view would be located at for the purpose of tab expansion >= 0.
    e - how to expand the tabs when encountered.
  Returns:
    the desired span >= 0
  See Also:
    getTabbedSpan

getPartialSpan

     public float getPartialSpan(int p0,
                                 int p1)

  Determines the span along the same axis as tab expansion for a portion of the view. This is intended for use by the TabExpander for cases where the tab expansion involves aligning the portion of text that doesn't have whitespace relative to the tab stop. There is therefore an assumption that the range given does not contain tabs.

  This method can be called while servicing the getTabbedSpan or getPreferredSize. It has to arrange for its own text buffer to make the measurements.

  Parameters:
    p0 - the starting document offset >= 0
    p1 - the ending document offset >= p0
  Returns:
    the span >= 0

paint

     public void paint(Graphics g,
                       Shape a)

  Renders a portion of a text style run.

  Parameters:
    g - the rendering surface to use
    a - the allocated region to render into
  Overrides:
    paint in class View

getPreferredSpan

     public float getPreferredSpan(int axis)

  Determines the preferred span for this view along an axis.

  Parameters:
    axis - may be either View.X_AXIS or View.Y_AXIS
  Returns:
    s the span the view would like to be rendered into >= 0. Typically the view is told to render into the span that is returned, although there is no guarantee. The parent may choose to resize or break the view.
  Overrides:
    getPreferredSpan in class View

getAlignment

     public float getAlignment(int axis)

  Determines the desired alignment for this view along an axis. For the label, the alignment is along the font baseline for the y axis, and the superclasses alignment along the x axis.

  Parameters:
    axis - may be either View.X_AXIS or View.Y_AXIS
  Returns:
    s 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.
  Overrides:
    getAlignment in class View

modelToView

     public Shape modelToView(int pos,
                              Shape a) throws BadLocationException

  Provides a mapping from the document model coordinate space to the coordinate space of the view mapped to it.

  Parameters:
    pos - the position to convert >= 0
    a - the allocated region to render into
  Returns:
    the bounding box of the given position
  Throws: BadLocationException
    if the given position does not represent a valid location in the associated document
  Overrides:
    modelToView in class View
  See Also:
    modelToView

viewToModel

     public int viewToModel(float x,
                            float y,
                            Shape a)

  Provides a mapping from the view coordinate space to the logical coordinate space of the model.

  Parameters:
    x - the X coordinate >= 0
    y - the Y coordinate >= 0
    a - the allocated region to render into
  Returns:
    the location within the model that best represents the given point of view >= 0
  Overrides:
    viewToModel in class View
  See Also:
    viewToModel

changedUpdate

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

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

  Parameters:
    e - 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 View
  See Also:
    changedUpdate

getBreakWeight

     public int getBreakWeight(int axis,
                               float pos,
                               float len)

  Determines how attractive a break opportunity in this view is. This can be used for determining which view is the most attractive to call `breakView` on in the process of formatting. The higher the weight, the more attractive the break. A value equal to or lower than `View.BadBreakWeight` should not be considered for a break. A value greater than or equal to `View.ForcedBreakWeight` should be broken.

  This is implemented to forward to the superclass for the Y_AXIS. Along the X_AXIS the following values may be returned.

  View.ExcellentBreakWeight
    if there is whitespace proceeding the desired break location.
  View.BadBreakWeight
    if the desired break location results in a break location of the starting offset.
  View.GoodBreakWeight
    if the other conditions don't occur.
  This will normally result in the behavior of breaking on a whitespace location if one can be found, otherwise breaking between characters.

  Parameters:
    axis - may be either View.X_AXIS or View.Y_AXIS
    pos - the potential location of the start of the broken view >= 0. This may be useful for calculating tab positions.
    len - specifies the relative length from pos where a potential break is desired >= 0.
  Returns:
    the weight, which should be a value between View.ForcedBreakWeight and View.BadBreakWeight.
  Overrides:
    getBreakWeight in class View
  See Also:
    xv_LabelView, ParagraphView, BadBreakWeight, GoodBreakWeight, ExcellentBreakWeight, ForcedBreakWeight

breakView

     public View breakView(int axis,
                           int p0,
                           float pos,
                           float len)

  Breaks this view on the given axis at the given length. This is implemented to attempt to break on a whitespace location, and returns a fragment with the whitespace at the end. If a whitespace location can't be found, the nearest character is used.

  Parameters:
    axis - may be either View.X_AXIS or View.Y_AXIS
    p0 - the location in the model where the fragment should start it's representation >= 0.
    pos - the position along the axis that the broken view would occupy >= 0. This may be useful for things like tab calculations.
    len - specifies the distance along the axis where a potential break is desired >= 0.
  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.
  Overrides:
    breakView in class View
  See Also:
    breakView

createFragment

     public View createFragment(int p0,
                                int p1)

  Creates a view that represents a portion of the element. This is potentially useful during formatting operations for taking measurements of fragments of the view. If the view doesn't support fragmenting (the default), it should return itself.

  This view does support fragmenting. It is implemented to return a nested class that shares state in this view representing only a portion of the view.

  Parameters:
    p0 - the starting offset >= 0. This should be a value greater or equal to the element starting offset and less than the element ending offset.
    p1 - the ending offset > p0. This should be a value less than or equal to the elements end offset and greater than the elements starting offset.
  Returns:
    s the view fragment, or itself if the view doesn't support breaking into fragments.
  Overrides:
    createFragment in class View
  See Also:
    xv_LabelView

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