BlockView (Java Platform SE 8 )
Keywords: javax.swing.text.html.BlockView class
Date: 2017-01-22

javax.swing.text.html

## Class BlockView

- java.lang.Object
- - javax.swing.text.View
  - - javax.swing.text.CompositeView
    - - javax.swing.text.BoxView
      - - javax.swing.text.html.BlockView

- All Implemented Interfaces:
    SwingConstants
  Direct Known Subclasses:
    ListView

      public class BlockView
      extends BoxView

  A view implementation to display a block (as a box) with CSS specifications.

- - ### Field Summary

    - ### Fields inherited from class javax.swing.text.View

      `BadBreakWeight, ExcellentBreakWeight, ForcedBreakWeight, GoodBreakWeight, 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

    Constructors
    Constructor and Description
    `BlockView(Element elem, int axis)` Creates a new view that represents an html box.

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `protected SizeRequirements` | `calculateMajorAxisRequirements(int axis, SizeRequirements r)` Calculate the requirements of the block along the major axis (i.e.
    `protected SizeRequirements` | `calculateMinorAxisRequirements(int axis, SizeRequirements r)` Calculate the requirements of the block along the minor axis (i.e.
    `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.
    `float` | `getAlignment(int axis)` Gets the alignment.
    `AttributeSet` | `getAttributes()` Fetches the attributes to use when rendering.
    `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.
    `float` | `getPreferredSpan(int axis)` Determines the preferred span for this view along an axis.
    `int` | `getResizeWeight(int axis)` Gets the resize weight.
    `protected StyleSheet` | `getStyleSheet()`
    `protected void` | `layoutMinorAxis(int targetSpan, int axis, int[] offsets, int[] spans)` Performs layout for the minor axis of the box (i.e.
    `void` | `paint(Graphics g, Shape allocation)` Renders using the given rendering surface and area on that surface.
    `void` | `setParent(View parent)` Establishes the parent view for this view.
    `protected void` | `setPropertiesFromAttributes()` Update any cached values that come from attributes.

    - ### Methods inherited from class javax.swing.text.BoxView

      `baselineLayout, baselineRequirements, childAllocation, flipEastAndWestAtEnds, forwardUpdate, getAxis, getChildAllocation, getHeight, getOffset, getSpan, getViewAtPoint, getWidth, isAfter, isAllocationValid, isBefore, isLayoutValid, layout, layoutChanged, layoutMajorAxis, modelToView, paintChild, preferenceChanged, replace, setAxis, setSize, viewToModel`

    - ### Methods inherited from class javax.swing.text.CompositeView

      `getBottomInset, getInsideAllocation, getLeftInset, getNextEastWestVisualPositionFrom, getNextNorthSouthVisualPositionFrom, getNextVisualPositionFrom, getRightInset, getTopInset, getView, getViewAtPosition, getViewCount, getViewIndex, getViewIndexAtPosition, loadChildren, modelToView, setInsets, setParagraphInsets`

    - ### Methods inherited from class javax.swing.text.View

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

    - ### Methods inherited from class java.lang.Object

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

- - ### Constructor Detail

    - #### BlockView

          public BlockView(Element elem,
                           int axis)

      Creates a new view that represents an html box. This can be used for a number of elements.
      Parameters:
        `elem` - the element to create a view for
        `axis` - either View.X_AXIS or View.Y_AXIS

  - ### Method Detail

    - #### setParent

          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 implemented to forward to the superclass as well as call the `setPropertiesFromAttributes()` method to set the paragraph properties from the css attributes. The call is made at this time to ensure the ability to resolve upward through the parents view attributes.

      Overrides:
        `setParent` in class `CompositeView`
      Parameters:
        `parent` - the new parent, or null if the view is being removed from a parent it was previously added to

    - #### calculateMajorAxisRequirements

          protected SizeRequirements calculateMajorAxisRequirements(int axis,
                                                                    SizeRequirements r)

      Calculate the requirements of the block along the major axis (i.e. the axis along with it tiles). This is implemented to provide the superclass behavior and then adjust it if the CSS width or height attribute is specified and applicable to the axis.
      Overrides:
        `calculateMajorAxisRequirements` in class `BoxView`
      Parameters:
        `axis` - the axis being studied
        `r` - the `SizeRequirements` object; if `null` one will be created
      Returns:
        the newly initialized `SizeRequirements` object
      See Also:
        `SizeRequirements`

    - #### calculateMinorAxisRequirements

          protected SizeRequirements calculateMinorAxisRequirements(int axis,
                                                                    SizeRequirements r)

      Calculate the requirements of the block along the minor axis (i.e. the axis orthogonal to the axis along with it tiles). This is implemented to provide the superclass behavior and then adjust it if the CSS width or height attribute is specified and applicable to the axis.
      Overrides:
        `calculateMinorAxisRequirements` in class `BoxView`
      Parameters:
        `axis` - the axis being studied
        `r` - the `SizeRequirements` object; if `null` one will be created
      Returns:
        the newly initialized `SizeRequirements` object
      See Also:
        `SizeRequirements`

    - #### 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.
      Overrides:
        `layoutMinorAxis` in class `BoxView`
      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

    - #### paint

          public void paint(Graphics g,
                            Shape allocation)

      Renders using the given rendering surface and area on that surface. This is implemented to delegate to the css box painter to paint the border and background prior to the interior.
      Overrides:
        `paint` in class `BoxView`
      Parameters:
        `g` - the rendering surface to use
        `allocation` - the allocated region to render into
      See Also:
        `View.paint(java.awt.Graphics, java.awt.Shape)`

    - #### getAttributes

          public AttributeSet getAttributes()

      Fetches the attributes to use when rendering. This is implemented to multiplex the attributes specified in the model with a StyleSheet.
      Overrides:
        `getAttributes` in class `View`

    - #### getResizeWeight

          public int getResizeWeight(int axis)

      Gets the resize weight.
      Overrides:
        `getResizeWeight` in class `BoxView`
      Parameters:
        `axis` - may be either X_AXIS or Y_AXIS
      Returns:
        the weight
      Throws:
        `IllegalArgumentException` - for an invalid axis

    - #### getAlignment

          public float getAlignment(int axis)

      Gets the alignment.
      Overrides:
        `getAlignment` in class `BoxView`
      Parameters:
        `axis` - may be either X_AXIS or Y_AXIS
      Returns:
        the alignment

    - #### changedUpdate

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

      Description copied from class: `View`
      Gives notification from the document that attributes were changed in a location that this view is responsible for. To reduce the burden to subclasses, this functionality is spread out into the following calls that subclasses can reimplement:
      1. `updateChildren` is called if there were any changes to the element this view is responsible for. If this view has child views that are represent the child elements, then this method should do whatever is necessary to make sure the child views correctly represent the model.
      2. `forwardUpdate` is called to forward the DocumentEvent to the appropriate child views.
      3. `updateLayout` is called to give the view a chance to either repair its layout, to reschedule layout, or do nothing.
      Overrides:
        `changedUpdate` in class `View`
      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)`

    - #### getPreferredSpan

          public float getPreferredSpan(int axis)

      Determines the preferred span for this view along an axis.
      Overrides:
        `getPreferredSpan` in class `BoxView`
      Parameters:
        `axis` - may be either `View.X_AXIS` or `View.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 class `BoxView`
      Parameters:
        `axis` - may be either `View.X_AXIS` or `View.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 class `BoxView`
      Parameters:
        `axis` - may be either `View.X_AXIS` or `View.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)`

    - #### setPropertiesFromAttributes

          protected void setPropertiesFromAttributes()

      Update any cached values that come from attributes.

    - #### getStyleSheet

          protected StyleSheet getStyleSheet()

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