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Class com.sun.java.swing.text.View

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

public abstract class View

extends Object

BadBreakWeight

The weight to indicate a view is a bad break opportunity for the purpose of formatting.

ExcellentBreakWeight

The weight to indicate a view supports breaking, and this represents a very attractive place to break.

ForcedBreakWeight

The weight to indicate a view supports breaking, and must be broken to be represented properly when placed in a view that formats it's children by breaking them.

GoodBreakWeight

The weight to indicate a view supports breaking, but better opportunities probably exist.

X_AXIS

Axis for format/break operations.

Y_AXIS

Axis for format/break operations.

View(Element)

Creates a new View object.

breakView(int, int, float, float)

Tries to break this view on the given axis.

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)

Create 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.

getChildAllocation(int, Shape)

Fetches the allocation for the given child view.

getContainer()

Fetches the container hosting the view.

getDocument()

Fetches the model associated with the view.

getElement()

Fetches the structural portion of the subject that this view is mapped to.

getEndOffset()

Fetches the portion of the model that this view is responsible for.

getParent()

Returns the parent of the view.

getPreferredSpan(int)

Determines the preferred span for this view along an axis.

getResizeWeight(int)

Determines the resizability of the view along the given axis.

getStartOffset()

Fetches the portion of the model that this view is responsible for.

getView(int)

Gets the nth child view.

getViewCount()

Returns the number of views in this view.

getViewFactory()

Fetches the ViewFactory implementation that is feeding the view hierarchy.

insertUpdate(DocumentEvent, Shape, ViewFactory)

Gives notification that something was inserted into the document in a location that this view is responsible for.

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 using the given rendering surface and area on that surface.

preferenceChanged(View, boolean, boolean)

Child views can call this on the parent to indicate that the preference has changed and should be reconsidered for layout.

removeUpdate(DocumentEvent, Shape, ViewFactory)

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

setParent(View)

Establishes the parent view for this view.

setSize(float, float)

Sets the size of the view.

viewToModel(float, float, Shape)

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

 public static final int BadBreakWeight

The weight to indicate a view is a bad break opportunity for the purpose of formatting. This value indicates that no attempt should be made to break the view into fragments as the view has not been written to support fragmenting.

See Also:

getBreakWeight, GoodBreakWeight, ExcellentBreakWeight, ForcedBreakWeight

 public static final int GoodBreakWeight

The weight to indicate a view supports breaking, but better opportunities probably exist.

See Also:

getBreakWeight, BadBreakWeight, GoodBreakWeight, ExcellentBreakWeight, ForcedBreakWeight

 public static final int ExcellentBreakWeight

The weight to indicate a view supports breaking, and this represents a very attractive place to break.

See Also:

getBreakWeight, BadBreakWeight, GoodBreakWeight, ExcellentBreakWeight, ForcedBreakWeight

 public static final int ForcedBreakWeight

The weight to indicate a view supports breaking, and must be broken to be represented properly when placed in a view that formats it's children by breaking them.

See Also:

getBreakWeight, BadBreakWeight, GoodBreakWeight, ExcellentBreakWeight, ForcedBreakWeight

 public static final int X_AXIS

Axis for format/break operations.

 public static final int Y_AXIS

Axis for format/break operations.

 public View(Element elem)

Creates a new View object.

Parameters:

elem - the element to represent

 protected final View getParent()

Returns the parent of the view.

Returns:

the parent, null if none

 public abstract 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. 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.

See Also:

getPreferredSpan

 public void preferenceChanged(View child,
                               boolean width,
                               boolean height)

Child views can call this on the parent to indicate that the preference has changed and should be reconsidered for layout. By default this just propagates upward to the next parent. The root view will call revalidate on the associated text component.

Parameters:

child - the child view

width - true if the width preference has changed

height - true if the height preference has changed

See Also:

revalidate

 public float getAlignment(int axis)

Determines the desired alignment for this view along an axis. By default this is simply centered.

Parameters:

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

Returns:

s The desired alignment. This should be a value >= 0.0 and <= 1.0 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.

 public abstract void paint(Graphics g,
                            Shape allocation)

Renders using the given rendering surface and area on that surface. The view may need to do layout and create child views to enable itself to render into the given allocation.

Parameters:

g - the rendering surface to use

allocation - the allocated region to render into

See Also:

paint

 public void setParent(View parent)

Establishes the parent view for this view. This is guaranteed to be called before any other methods if the parent view is functioning properly. This is also the last method called, since it is called to indicate the view has been removed from the hierarchy as well. If this is reimplemented, super.setParent() should be called.

Parameters:

parent - the new parent, or null if the view is being removed from a parent it was previously added to

 public int getViewCount()

Returns the number of views in this view. Since the default is to not be a composite view this returns 0.

Returns:

the number of views >= 0

See Also:

getViewCount

 public View getView(int n)

Gets the nth child view. Since there are no children by default, this returns null.

Parameters:

n - the number of the view to get, >= 0 && < getViewCount()

Returns:

the view

 public Shape getChildAllocation(int index,
                                 Shape a)

Fetches the allocation for the given child view. This enables finding out where various views are located, without assuming the views store their location. This returns null since the default is to not have any child views.

Parameters:

index - the index of the child, >= 0 && < getViewCount()

a - the allocation to this view.

Returns:

the allocation to the child

 public abstract 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 is returned

Throws: BadLocationException

if the given position does not represent a valid location in the associated document

See Also:

modelToView

 public abstract 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 in the view >= 0

See Also:

viewToModel

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

Gives notification that something was inserted into the document 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

See Also:

insertUpdate

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

Gives notification from the document that attributes were removed 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

See Also:

removeUpdate

 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

See Also:

changedUpdate

 public Document getDocument()

Fetches the model associated with the view.

Returns:

the view model, null if none

See Also:

getDocument

 public int getStartOffset()

Fetches the portion of the model that this view is responsible for.

Returns:

the starting offset into the model >= 0

See Also:

getStartOffset

 public int getEndOffset()

Fetches the portion of the model that this view is responsible for.

Returns:

the ending offset into the model >= 0

See Also:

getEndOffset

 public Element getElement()

Fetches the structural portion of the subject that this view is mapped to. The view may not be responsible for the entire portion of the element.

Returns:

the subject

See Also:

getElement

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

Tries to break this view on the given axis. This is called by views that try to do formatting of their children. For example, a view of a paragraph will typically try to place its children into row and views representing chunks of text can sometimes be broken down into smaller pieces.

This is implemented to return the view itself, which represents the default behavior on not being breakable. If the view does support breaking, the starting offset of the view returned should be the given offset, and the end offset should be less than or equal to the end offset of the view being broken.

Parameters:

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

offset - the location in the document model that a broken fragment would occupy >= 0. This would be the starting offset of the fragment returned.

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.

See Also:

ParagraphView

 public View createFragment(int p0,
                            int p1)

Create 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.

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.

See Also:

LabelView

 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. A view that represents text that has whitespace in it might be more attractive than a view that has no whitespace, for example. The higher the weight, the more attractive the break. A value equal to or lower than BadBreakWeight should not be considered for a break. A value greater than or equal to ForcedBreakWeight should be broken.

This is implemented to provide the default behavior of returning BadBreakWeight unless the length is greater than the length of the view in which case the entire view represents the fragment. Unless a view has been written to support breaking behavior, it is not attractive to try and break the view. An example of a view that does support breaking is LabelView. An example of a view that uses break weight is ParagraphView.

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 ForcedBreakWeight and BadBreakWeight.

See Also:

LabelView, ParagraphView, BadBreakWeight, GoodBreakWeight, ExcellentBreakWeight, ForcedBreakWeight

 public int getResizeWeight(int axis)

Determines the resizability of the view along the given axis. A value of 0 or less is not resizable.

Parameters:

axis - View.X_AXIS or View.Y_AXIS

Returns:

the weight

 public void setSize(float width,
                     float height)

Sets the size of the view. This should cause layout of the view, if it has any layout duties. The default is to do nothing.

Parameters:

width - the width >= 0

height - the height >= 0

 public Container getContainer()

Fetches the container hosting the view. This is useful for things like scheduling a repaint, finding out the host components font, etc. The default implementation of this is to forward the query to the parent view.

Returns:

the container, null if none

 public ViewFactory getViewFactory()

Fetches the ViewFactory implementation that is feeding the view hierarchy. Normally the views are given this as an argument to updates from the model when they are most likely to need the factory, but this method serves to provide it at other times.

Returns:

the factory, null if none

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