Module java.desktop
Package javax.swing.text

Class ParagraphView

  • All Implemented Interfaces:
    SwingConstants, TabExpander
    Direct Known Subclasses:
    ParagraphView

    public class ParagraphView
extends FlowView
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

    • Field Detail

      • firstLineIndent

        protected int firstLineIndent
        Indentation for the first line, from the left inset.

    • 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

      • setJustification

        protected void setJustification​(int j)
        Sets the type of justification.
        Parameters:
        j - one of the following values:
        • StyleConstants.ALIGN_LEFT
        • StyleConstants.ALIGN_CENTER
        • StyleConstants.ALIGN_RIGHT

      • setLineSpacing

        protected void setLineSpacing​(float ls)
        Sets the line spacing.
        Parameters:
        ls - the value is a factor of the line hight

      • setFirstLineIndent

        protected void setFirstLineIndent​(float fi)
        Sets the indent on the first line.
        Parameters:
        fi - the value in points

      • setPropertiesFromAttributes

        protected void setPropertiesFromAttributes​()
        Set the cached properties from the attributes.

      • getLayoutViewCount

        protected int getLayoutViewCount​()
        Returns the number of views that this view is responsible for. The child views of the paragraph are rows which have been used to arrange pieces of the Views that represent the child elements. This is the number of views that have been tiled in two dimensions, and should be equivalent to the number of child elements to the element this view is responsible for.
        Returns:
        the number of views that this ParagraphView is responsible for

      • getLayoutView

        protected View getLayoutView​(int index)
        Returns the view at a given index. The child views of the paragraph are rows which have been used to arrange pieces of the Views that represent the child elements. This methods returns the view responsible for the child element index (prior to breaking). These are the Views that were produced from a factory (to represent the child elements) and used for layout.
        Parameters:
        index - the index of the desired view
        Returns:
        the view at index

      • getClosestPositionTo

        protected int getClosestPositionTo​(int pos,
                                   Position.Bias b,
                                   Shape a,
                                   int direction,
                                   Position.Bias[] biasRet,
                                   int rowIndex,
                                   int x)
                            throws BadLocationException
        Returns the closest model position to x. rowIndex gives the index of the view that corresponds that should be looked in.
        Parameters:
        pos - position into the model
        b - the bias
        a - the allocated region to render into
        direction - one of the following values:
        • SwingConstants.NORTH
        • SwingConstants.SOUTH
        biasRet - an array containing the bias that were checked in this method
        rowIndex - the index of the view
        x - the x coordinate of interest
        Returns:
        the closest model position to x
        Throws:
        BadLocationException - if a bad location is encountered

      • 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 Views 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 Views are layed out in descending order.

        This will return true if the text is layed out right to left at position, otherwise false.

        Overrides:
        flipEastAndWestAtEnds in class BoxView
        Parameters:
        position - position into the model
        bias - either Position.Bias.Forward or Position.Bias.Backward
        Returns:
        true if the text is layed out right to left at position, otherwise false.

      • getFlowSpan

        public int getFlowSpan​(int index)
        Fetches the constraining span to flow against for the given child index.
        Overrides:
        getFlowSpan in class FlowView
        Parameters:
        index - the index of the view being queried
        Returns:
        the constraining span for the given view at index
        Since:
        1.3
        See Also:
        FlowView.getFlowStart(int)

      • getFlowStart

        public int getFlowStart​(int index)
        Fetches the location along the flow axis that the flow span will start at.
        Overrides:
        getFlowStart in class FlowView
        Parameters:
        index - the index of the view being queried
        Returns:
        the location for the given view at index
        Since:
        1.3
        See Also:
        FlowView.getFlowSpan(int)

      • createRow

        protected View createRow​()
        Create a View that should be used to hold a a row's worth of children in a flow.
        Specified by:
        createRow in class FlowView
        Returns:
        the new View
        Since:
        1.3

      • 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 its 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, its settings will be used, otherwise a default expansion will be provided. The base location for tab expansion is the left inset from the paragraphs most recent allocation (which is what the layout of the children is based upon).

        Specified by:
        nextTabStop in interface TabExpander
        Parameters:
        x - the X reference position
        tabOffset - the position within the text stream that the tab occurred at >= 0
        Returns:
        the trailing end of the tab expansion >= 0
        See Also:
        TabSet, TabStop, LabelView

      • getTabSet

        protected TabSet getTabSet​()
        Gets the Tabset to be used in calculating tabs.
        Returns:
        the TabSet

      • 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.
        Parameters:
        startOffset - the starting document offset >= 0
        endOffset - the ending document offset >= startOffset
        Returns:
        the size >= 0

      • 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.
        Parameters:
        string - the string of characters
        start - where to start in the model >= 0
        Returns:
        the document offset, or -1 if no characters found

      • getTabBase

        protected float getTabBase​()
        Returns where the tabs are calculated from.
        Returns:
        where tabs are calculated from

      • paint

        public void paint​(Graphics g,
                  Shape a)
        Renders using the given rendering surface and area on that surface. This is implemented to delegate to the superclass after stashing the base coordinate for tab calculations.
        Overrides:
        paint in class BoxView
        Parameters:
        g - the rendering surface to use
        a - the allocated region to render into
        See Also:
        View.paint(java.awt.Graphics, java.awt.Shape)

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

      • 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 View.X_AXIS or View.Y_AXIS
        len - specifies where a potential break is desired along the given axis >= 0
        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:
        View.breakView(int, int, float, float)

      • getBreakWeight

        public int getBreakWeight​(int axis,
                          float len)
        Gets the break weight for a given location.

        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 View.X_AXIS or View.Y_AXIS
        len - specifies where a potential break is desired >= 0
        Returns:
        a value indicating the attractiveness of breaking here; either GoodBreakWeight or BadBreakWeight
        See Also:
        View.getBreakWeight(int, float, float)

      • calculateMinorAxisRequirements

        protected SizeRequirements calculateMinorAxisRequirements​(int axis,
                                                          SizeRequirements r)
        Calculate the needs for the paragraph along the minor axis.

        This uses size requirements of the superclass, modified to take into account the non-breakable areas at the adjacent views edges. The minimal size requirements for such views should be no less than the sum of all adjacent fragments.

        If the axis parameter is neither View.X_AXIS nor View.Y_AXIS, IllegalArgumentException is thrown. If the r parameter is null, a new SizeRequirements object is created, otherwise the supplied SizeRequirements object is returned.

        Overrides:
        calculateMinorAxisRequirements in class FlowView
        Parameters:
        axis - the minor axis
        r - the input SizeRequirements object
        Returns:
        the new or adjusted SizeRequirements object
        Throws:
        IllegalArgumentException - if the axis parameter is invalid
        See Also:
        SizeRequirements