Class BoxView
- java.lang.Object
-
- javax.swing.text.View
-
- javax.swing.text.CompositeView
-
- javax.swing.text.BoxView
- All Implemented Interfaces:
SwingConstants
- Direct Known Subclasses:
-
BlockView
,FlowView
,TableView
,TableView.TableCell
,TableView.TableRow
,WrappedPlainView
,ZoneView
public class BoxView extends CompositeView
A view that arranges its children into a box shape by tiling its children along an axis. The box is somewhat like that found in TeX where there is alignment of the children, flexibility of the children is considered, etc. This is a building block that might be useful to represent things like a collection of lines, paragraphs, lists, columns, pages, etc. The axis along which the children are tiled is considered the major axis. The orthogonal axis is the minor axis.
Layout for each axis is handled separately by the methods layoutMajorAxis
and layoutMinorAxis
. Subclasses can change the layout algorithm by reimplementing these methods. These methods will be called as necessary depending upon whether or not there is cached layout information and the cache is considered valid. These methods are typically called if the given size along the axis changes, or if layoutChanged
is called to force an updated layout. The layoutChanged
method invalidates cached layout information, if there is any. The requirements published to the parent view are calculated by the methods calculateMajorAxisRequirements
and calculateMinorAxisRequirements
. If the layout algorithm is changed, these methods will likely need to be reimplemented.
Field Summary
Fields declared in class javax.swing.text.View
BadBreakWeight, ExcellentBreakWeight, ForcedBreakWeight, GoodBreakWeight, X_AXIS, Y_AXIS
Fields declared in 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
Constructor | Description |
---|---|
BoxView(Element elem,
int axis) | Constructs a |
Method Summary
Modifier and Type | Method | Description |
---|---|---|
protected void | baselineLayout(int targetSpan,
int axis,
int[] offsets,
int[] spans) | Computes the location and extent of each child view in this |
protected SizeRequirements | baselineRequirements(int axis,
SizeRequirements r) | Calculates the size requirements for this |
protected SizeRequirements | calculateMajorAxisRequirements(int axis,
SizeRequirements r) | Calculates the size requirements for the major axis |
protected SizeRequirements | calculateMinorAxisRequirements(int axis,
SizeRequirements r) | Calculates the size requirements for the minor axis |
protected void | childAllocation(int index,
Rectangle alloc) | Allocates a region for a child view. |
protected boolean | flipEastAndWestAtEnds(int position,
Position.Bias bias) | Determines in which direction the next view lays. |
protected void | forwardUpdate(DocumentEvent.ElementChange ec,
DocumentEvent e,
Shape a,
ViewFactory f) | Forwards the given |
float | getAlignment(int axis) | Determines the desired alignment for this view along an axis. |
int | getAxis() | Fetches the tile axis property. |
Shape | getChildAllocation(int index,
Shape a) | Fetches the allocation for the given child view. |
int | getHeight() | Returns the current height of the box. |
float | getMaximumSpan(int axis) | Determines the maximum span for this view along an axis. |
float | getMinimumSpan(int axis) | Determines the minimum span for this view along an axis. |
protected int | getOffset(int axis,
int childIndex) | Fetches the offset of a particular child's current layout. |
float | getPreferredSpan(int axis) | Determines the preferred span for this view along an axis. |
int | getResizeWeight(int axis) | Gets the resize weight. |
protected int | getSpan(int axis,
int childIndex) | Fetches the span of a particular child's current layout. |
protected View | getViewAtPoint(int x,
int y,
Rectangle alloc) | Fetches the child view at the given coordinates. |
int | getWidth() | Returns the current width of the box. |
protected boolean | isAfter(int x,
int y,
Rectangle innerAlloc) | Determines if a point falls after an allocated region. |
protected boolean | isAllocationValid() | Are the allocations for the children still valid? |
protected boolean | isBefore(int x,
int y,
Rectangle innerAlloc) | Determines if a point falls before an allocated region. |
protected boolean | isLayoutValid(int axis) | Determines if the layout is valid along the given axis. |
protected void | layout(int width,
int height) | Perform layout on the box |
void | layoutChanged(int axis) | Invalidates the layout along an axis. |
protected void | layoutMajorAxis(int targetSpan,
int axis,
int[] offsets,
int[] spans) | Performs layout for the major axis of the box (i.e. the axis that it represents). |
protected void | layoutMinorAxis(int targetSpan,
int axis,
int[] offsets,
int[] spans) | Performs layout for the minor axis of the box (i.e. the axis orthogonal to the axis that it represents). |
Shape | modelToView(int pos,
Shape a,
Position.Bias b) | Provides a mapping from the document model coordinate space to the coordinate space of the view mapped to it. |
void | paint(Graphics g,
Shape allocation) | Renders the |
protected void | paintChild(Graphics g,
Rectangle alloc,
int index) | Paints a child. |
void | preferenceChanged(View child,
boolean width,
boolean height) | This is called by a child to indicate its preferred span has changed. |
void | replace(int index,
int length,
View[] elems) | Invalidates the layout and resizes the cache of requests/allocations. |
void | setAxis(int axis) | Sets the tile axis property. |
void | setSize(float width,
float height) | Sets the size of the view. |
int | viewToModel(float x,
float y,
Shape a,
Position.Bias[] bias) | Provides a mapping from the view coordinate space to the logical coordinate space of the model. |
Methods declared in class javax.swing.text.CompositeView
getBottomInset, getInsideAllocation, getLeftInset, getNextEastWestVisualPositionFrom, getNextNorthSouthVisualPositionFrom, getNextVisualPositionFrom, getRightInset, getTopInset, getView, getViewAtPosition, getViewCount, getViewIndex, getViewIndexAtPosition, loadChildren, modelToView, setInsets, setParagraphInsets, setParent
Methods declared in class javax.swing.text.View
append, breakView, changedUpdate, createFragment, forwardUpdateToView, getAttributes, getBreakWeight, getContainer, getDocument, getElement, getEndOffset, getGraphics, getParent, getStartOffset, getToolTipText, getViewFactory, getViewIndex, insert, insertUpdate, isVisible, modelToView, remove, removeAll, removeUpdate, updateChildren, updateLayout, viewToModel
Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Constructor Detail
BoxView
public BoxView(Element elem, int axis)
Constructs a BoxView
.
- Parameters:
-
elem
- the element this view is responsible for -
axis
- eitherView.X_AXIS
orView.Y_AXIS
Method Detail
getAxis
public int getAxis()
Fetches the tile axis property. This is the axis along which the child views are tiled.
- Returns:
- the major axis of the box, either
View.X_AXIS
orView.Y_AXIS
- Since:
- 1.3
setAxis
public void setAxis(int axis)
Sets the tile axis property. This is the axis along which the child views are tiled.
- Parameters:
-
axis
- eitherView.X_AXIS
orView.Y_AXIS
- Since:
- 1.3
layoutChanged
public void layoutChanged(int axis)
Invalidates the layout along an axis. This happens automatically if the preferences have changed for any of the child views. In some cases the layout may need to be recalculated when the preferences have not changed. The layout can be marked as invalid by calling this method. The layout will be updated the next time the setSize
method is called on this view (typically in paint).
- Parameters:
-
axis
- eitherView.X_AXIS
orView.Y_AXIS
- Since:
- 1.3
isLayoutValid
protected boolean isLayoutValid(int axis)
Determines if the layout is valid along the given axis.
- Parameters:
-
axis
- eitherView.X_AXIS
orView.Y_AXIS
- Returns:
- if the layout is valid along the given axis
- Since:
- 1.4
paintChild
protected void paintChild(Graphics g, Rectangle alloc, int index)
Paints a child. By default that is all it does, but a subclass can use this to paint things relative to the child.
- Parameters:
-
g
- the graphics context -
alloc
- the allocated region to paint into -
index
- the child index, >= 0 && < getViewCount()
replace
public void replace(int index, int length, View[] elems)
Invalidates the layout and resizes the cache of requests/allocations. The child allocations can still be accessed for the old layout, but the new children will have an offset and span of 0.
- Overrides:
-
replace
in classCompositeView
- Parameters:
-
index
- the starting index into the child views to insert the new views; this should be a value >= 0 and <= getViewCount -
length
- the number of existing child views to remove; This should be a value >= 0 and <= (getViewCount() - offset) -
elems
- the child views to add; this value can benull
to indicate no children are being added (useful to remove)
forwardUpdate
protected void forwardUpdate(DocumentEvent.ElementChange ec, DocumentEvent e, Shape a, ViewFactory f)
Forwards the given DocumentEvent
to the child views that need to be notified of the change to the model. If a child changed its requirements and the allocation was valid prior to forwarding the portion of the box from the starting child to the end of the box will be repainted.
- Overrides:
-
forwardUpdate
in classView
- Parameters:
-
ec
- changes to the element this view is responsible for (may benull
if there were no changes) -
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 - Since:
- 1.3
- See Also:
-
View.insertUpdate(javax.swing.event.DocumentEvent, java.awt.Shape, javax.swing.text.ViewFactory)
,View.removeUpdate(javax.swing.event.DocumentEvent, java.awt.Shape, javax.swing.text.ViewFactory)
,View.changedUpdate(javax.swing.event.DocumentEvent, java.awt.Shape, javax.swing.text.ViewFactory)
preferenceChanged
public void preferenceChanged(View child, boolean width, boolean height)
This is called by a child to indicate its preferred span has changed. This is implemented to throw away cached layout information so that new calculations will be done the next time the children need an allocation.
- Overrides:
-
preferenceChanged
in classView
- Parameters:
-
child
- the child view -
width
- true if the width preference should change -
height
- true if the height preference should change - See Also:
JComponent.revalidate()
getResizeWeight
public int getResizeWeight(int axis)
Gets the resize weight. A value of 0 or less is not resizable.
- Overrides:
-
getResizeWeight
in classView
- Parameters:
-
axis
- may be eitherView.X_AXIS
orView.Y_AXIS
- Returns:
- the weight
- Throws:
-
IllegalArgumentException
- for an invalid axis
setSize
public void setSize(float width, float height)
Sets the size of the view. This should cause layout of the view if the view caches any layout information. This is implemented to call the layout method with the sizes inside of the insets.
paint
public void paint(Graphics g, Shape allocation)
Renders the BoxView
using the given rendering surface and area on that surface. Only the children that intersect the clip bounds of the given Graphics
will be rendered.
- Specified by:
-
paint
in classView
- Parameters:
-
g
- the rendering surface to use -
allocation
- the allocated region to render into - See Also:
View.paint(java.awt.Graphics, java.awt.Shape)
getChildAllocation
public Shape getChildAllocation(int index, Shape a)
Fetches the allocation for the given child view. This enables finding out where various views are located. This is implemented to return null
if the layout is invalid, otherwise the superclass behavior is executed.
- Overrides:
-
getChildAllocation
in classCompositeView
- Parameters:
-
index
- the index of the child, >= 0 && > getViewCount() -
a
- the allocation to this view - Returns:
- the allocation to the child; or
null
ifa
isnull
; ornull
if the layout is invalid
modelToView
public Shape modelToView(int pos, Shape a, Position.Bias b) throws BadLocationException
Provides a mapping from the document model coordinate space to the coordinate space of the view mapped to it. This makes sure the allocation is valid before calling the superclass.
- Overrides:
-
modelToView
in classCompositeView
- Parameters:
-
pos
- the position to convert >= 0 -
a
- the allocated region to render into -
b
- a bias value of eitherPosition.Bias.Forward
orPosition.Bias.Backward
- Returns:
- the bounding box of the given position
- Throws:
-
BadLocationException
- if the given position does not represent a valid location in the associated document - See Also:
View.modelToView(int, java.awt.Shape, javax.swing.text.Position.Bias)
viewToModel
public int viewToModel(float x, float y, Shape a, Position.Bias[] bias)
Provides a mapping from the view coordinate space to the logical coordinate space of the model.
- Overrides:
-
viewToModel
in classCompositeView
- Parameters:
-
x
- x coordinate of the view location to convert >= 0 -
y
- y coordinate of the view location to convert >= 0 -
a
- the allocated region to render into -
bias
- eitherPosition.Bias.Forward
orPosition.Bias.Backward
- Returns:
- the location within the model that best represents the given point in the view >= 0
- See Also:
View.viewToModel(float, float, java.awt.Shape, javax.swing.text.Position.Bias[])
getAlignment
public float getAlignment(int axis)
Determines the desired alignment for this view along an axis. This is implemented to give the total alignment needed to position the children with the alignment points lined up along the axis orthogonal to the axis that is being tiled. The axis being tiled will request to be centered (i.e. 0.5f).
- Overrides:
-
getAlignment
in classView
- Parameters:
-
axis
- may be eitherView.X_AXIS
orView.Y_AXIS
- Returns:
- the desired alignment >= 0.0f && <= 1.0f; this should be a value between 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
- Throws:
-
IllegalArgumentException
- for an invalid axis
getPreferredSpan
public float getPreferredSpan(int axis)
Determines the preferred span for this view along an axis.
- Specified by:
-
getPreferredSpan
in classView
- Parameters:
-
axis
- may be eitherView.X_AXIS
orView.Y_AXIS
- Returns:
- 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
- Throws:
-
IllegalArgumentException
- for an invalid axis type - See Also:
View.getPreferredSpan(int)
getMinimumSpan
public float getMinimumSpan(int axis)
Determines the minimum span for this view along an axis.
- Overrides:
-
getMinimumSpan
in classView
- Parameters:
-
axis
- may be eitherView.X_AXIS
orView.Y_AXIS
- Returns:
- 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
- Throws:
-
IllegalArgumentException
- for an invalid axis type - See Also:
View.getPreferredSpan(int)
getMaximumSpan
public float getMaximumSpan(int axis)
Determines the maximum span for this view along an axis.
- Overrides:
-
getMaximumSpan
in classView
- Parameters:
-
axis
- may be eitherView.X_AXIS
orView.Y_AXIS
- Returns:
- 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
- Throws:
-
IllegalArgumentException
- for an invalid axis type - See Also:
View.getPreferredSpan(int)
isAllocationValid
protected boolean isAllocationValid()
Are the allocations for the children still valid?
- Returns:
- true if allocations still valid
isBefore
protected boolean isBefore(int x, int y, Rectangle innerAlloc)
Determines if a point falls before an allocated region.
- Specified by:
-
isBefore
in classCompositeView
- Parameters:
-
x
- the X coordinate >= 0 -
y
- the Y coordinate >= 0 -
innerAlloc
- the allocated region; this is the area inside of the insets - Returns:
- true if the point lies before the region else false
isAfter
protected boolean isAfter(int x, int y, Rectangle innerAlloc)
Determines if a point falls after an allocated region.
- Specified by:
-
isAfter
in classCompositeView
- Parameters:
-
x
- the X coordinate >= 0 -
y
- the Y coordinate >= 0 -
innerAlloc
- the allocated region; this is the area inside of the insets - Returns:
- true if the point lies after the region else false
getViewAtPoint
protected View getViewAtPoint(int x, int y, Rectangle alloc)
Fetches the child view at the given coordinates.
- Specified by:
-
getViewAtPoint
in classCompositeView
- Parameters:
-
x
- the X coordinate >= 0 -
y
- the Y coordinate >= 0 -
alloc
- the parents inner allocation on entry, which should be changed to the child's allocation on exit - Returns:
- the view
childAllocation
protected void childAllocation(int index, Rectangle alloc)
Allocates a region for a child view.
- Specified by:
-
childAllocation
in classCompositeView
- Parameters:
-
index
- the index of the child view to allocate, >= 0 && < getViewCount() -
alloc
- the allocated region
layout
protected void layout(int width, int height)
Perform layout on the box
- Parameters:
-
width
- the width (inside of the insets) >= 0 -
height
- the height (inside of the insets) >= 0
getWidth
public int getWidth()
Returns the current width of the box. This is the width that it was last allocated.
- Returns:
- the current width of the box
getHeight
public int getHeight()
Returns the current height of the box. This is the height that it was last allocated.
- Returns:
- the current height of the box
layoutMajorAxis
protected void layoutMajorAxis(int targetSpan, int axis, int[] offsets, int[] spans)
Performs layout for the major axis of the box (i.e. the axis that it represents). The results of the layout (the offset and span for each children) are placed in the given arrays which represent the allocations to the children along the major axis.
- Parameters:
-
targetSpan
- the total span given to the view, which would be used to layout the children -
axis
- the axis being layed out -
offsets
- the offsets from the origin of the view for each of the child views; this is a return value and is filled in by the implementation of this method -
spans
- the span of each child view; this is a return value and is filled in by the implementation of this method
layoutMinorAxis
protected void layoutMinorAxis(int targetSpan, int axis, int[] offsets, int[] spans)
Performs layout for the minor axis of the box (i.e. the axis orthogonal to the axis that it represents). The results of the layout (the offset and span for each children) are placed in the given arrays which represent the allocations to the children along the minor axis.
- Parameters:
-
targetSpan
- the total span given to the view, which would be used to layout the children -
axis
- the axis being layed out -
offsets
- the offsets from the origin of the view for each of the child views; this is a return value and is filled in by the implementation of this method -
spans
- the span of each child view; this is a return value and is filled in by the implementation of this method
calculateMajorAxisRequirements
protected SizeRequirements calculateMajorAxisRequirements(int axis, SizeRequirements r)
Calculates the size requirements for the major axis axis
.
- Parameters:
-
axis
- the axis being studied -
r
- theSizeRequirements
object; ifnull
one will be created - Returns:
- the newly initialized
SizeRequirements
object - See Also:
SizeRequirements
calculateMinorAxisRequirements
protected SizeRequirements calculateMinorAxisRequirements(int axis, SizeRequirements r)
Calculates the size requirements for the minor axis axis
.
- Parameters:
-
axis
- the axis being studied -
r
- theSizeRequirements
object; ifnull
one will be created - Returns:
- the newly initialized
SizeRequirements
object - See Also:
SizeRequirements
baselineLayout
protected void baselineLayout(int targetSpan, int axis, int[] offsets, int[] spans)
Computes the location and extent of each child view in this BoxView
given the targetSpan
, which is the width (or height) of the region we have to work with.
- Parameters:
-
targetSpan
- the total span given to the view, which would be used to layout the children -
axis
- the axis being studied, eitherView.X_AXIS
orView.Y_AXIS
-
offsets
- an empty array filled by this method with values specifying the location of each child view -
spans
- an empty array filled by this method with values specifying the extent of each child view
baselineRequirements
protected SizeRequirements baselineRequirements(int axis, SizeRequirements r)
Calculates the size requirements for this BoxView
by examining the size of each child view.
- Parameters:
-
axis
- the axis being studied -
r
- theSizeRequirements
object; ifnull
one will be created - Returns:
- the newly initialized
SizeRequirements
object
getOffset
protected int getOffset(int axis, int childIndex)
Fetches the offset of a particular child's current layout.
- Parameters:
-
axis
- the axis being studied -
childIndex
- the index of the requested child - Returns:
- the offset (location) for the specified child
getSpan
protected int getSpan(int axis, int childIndex)
Fetches the span of a particular child's current layout.
- Parameters:
-
axis
- the axis being studied -
childIndex
- the index of the requested child - Returns:
- the span (width or height) of the specified child
flipEastAndWestAtEnds
protected boolean flipEastAndWestAtEnds(int position, Position.Bias bias)
Determines in which direction the next view lays. Consider the View at index n. Typically the View
s 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 View
s are layed out in descending order. Otherwise the method would return false indicating the View
s are layed out in ascending order.
If the receiver is laying its View
s along the Y_AXIS
, this will return the value from invoking the same method on the View
responsible for rendering position
and bias
. Otherwise this will return false.
- Overrides:
-
flipEastAndWestAtEnds
in classCompositeView
- Parameters:
-
position
- position into the model -
bias
- eitherPosition.Bias.Forward
orPosition.Bias.Backward
- Returns:
- true if the
View
s surrounding theView
responding for renderingposition
andbias
are layed out in descending order; otherwise false