Module java.desktop
Package javax.swing.text

Class GlyphView.GlyphPainter

  • Enclosing class:
    GlyphView
    public abstract static class GlyphView.GlyphPainter
extends Object
    A class to perform rendering of the glyphs. This can be implemented to be stateless, or to hold some information as a cache to facilitate faster rendering and model/view translation. At a minimum, the GlyphPainter allows a View implementation to perform its duties independent of a particular version of JVM and selection of capabilities (i.e. shaping for i18n, etc).
    Since:
    1.3

    • Constructor Detail

      • GlyphPainter

        public GlyphPainter()

    • Method Detail

      • getSpan

        public abstract float getSpan​(GlyphView v,
                              int p0,
                              int p1,
                              TabExpander e,
                              float x)
        Determine the span the glyphs given a start location (for tab expansion).
        Parameters:
        v - the GlyphView
        p0 - the beginning position
        p1 - the ending position
        e - how to expand the tabs when encountered
        x - the X coordinate
        Returns:
        the span the glyphs given a start location

      • getHeight

        public abstract float getHeight​(GlyphView v)
        Returns of the height.
        Parameters:
        v - the GlyphView
        Returns:
        of the height

      • getAscent

        public abstract float getAscent​(GlyphView v)
        Returns of the ascent.
        Parameters:
        v - the GlyphView
        Returns:
        of the ascent

      • getDescent

        public abstract float getDescent​(GlyphView v)
        Returns of the descent.
        Parameters:
        v - the GlyphView
        Returns:
        of the descent

      • paint

        public abstract void paint​(GlyphView v,
                           Graphics g,
                           Shape a,
                           int p0,
                           int p1)
        Paint the glyphs representing the given range.
        Parameters:
        v - the GlyphView
        g - the graphics context
        a - the current allocation of the view
        p0 - the beginning position
        p1 - the ending position

      • modelToView

        public abstract Shape modelToView​(GlyphView v,
                                  int pos,
                                  Position.Bias bias,
                                  Shape a)
                           throws BadLocationException
        Provides a mapping from the document model coordinate space to the coordinate space of the view mapped to it. This is shared by the broken views.
        Parameters:
        v - the GlyphView containing the destination coordinate space
        pos - the position to convert
        bias - either Position.Bias.Forward or Position.Bias.Backward
        a - Bounds of the View
        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 abstract int viewToModel​(GlyphView v,
                                float x,
                                float y,
                                Shape a,
                                Position.Bias[] biasReturn)
        Provides a mapping from the view coordinate space to the logical coordinate space of the model.
        Parameters:
        v - the GlyphView to provide a mapping for
        x - the X coordinate
        y - the Y coordinate
        a - the allocated region to render into
        biasReturn - either Position.Bias.Forward or Position.Bias.Backward is returned as the zero-th element of this array
        Returns:
        the location within the model that best represents the given point of view
        See Also:
        View.viewToModel(float, float, java.awt.Shape, javax.swing.text.Position.Bias[])

      • getBoundedPosition

        public abstract int getBoundedPosition​(GlyphView v,
                                       int p0,
                                       float x,
                                       float len)
        Determines the model location that represents the maximum advance that fits within the given span. This could be used to break the given view. The result should be a location just shy of the given advance. This differs from viewToModel which returns the closest position which might be proud of the maximum advance.
        Parameters:
        v - the view to find the model location to break at.
        p0 - the location in the model where the fragment should start it's representation >= 0.
        x - the graphic location along the axis that the broken view would occupy >= 0. This may be useful for things like tab calculations.
        len - specifies the distance into the view where a potential break is desired >= 0.
        Returns:
        the maximum model location possible for a break.
        See Also:
        View.breakView(int, int, float, float)

      • getPainter

        public GlyphView.GlyphPainter getPainter​(GlyphView v,
                                         int p0,
                                         int p1)
        Create a painter to use for the given GlyphView. If the painter carries state it can create another painter to represent a new GlyphView that is being created. If the painter doesn't hold any significant state, it can return itself. The default behavior is to return itself.
        Parameters:
        v - the GlyphView to provide a painter for
        p0 - the starting document offset >= 0
        p1 - the ending document offset >= p0
        Returns:
        a painter to use for the given GlyphView

      • getNextVisualPositionFrom

        public int getNextVisualPositionFrom​(GlyphView v,
                                     int pos,
                                     Position.Bias b,
                                     Shape a,
                                     int direction,
                                     Position.Bias[] biasRet)
                              throws BadLocationException
        Provides a way to determine the next visually represented model location that one might place a caret. Some views may not be visible, they might not be in the same order found in the model, or they just might not allow access to some of the locations in the model.
        Parameters:
        v - the view to use
        pos - the position to convert >= 0
        b - either Position.Bias.Forward or Position.Bias.Backward
        a - the allocated region to render into
        direction - the direction from the current position that can be thought of as the arrow keys typically found on a keyboard. This may be SwingConstants.WEST, SwingConstants.EAST, SwingConstants.NORTH, or SwingConstants.SOUTH.
        biasRet - either Position.Bias.Forward or Position.Bias.Backward is returned as the zero-th element of this array
        Returns:
        the location within the model that best represents the next location visual position.
        Throws:
        BadLocationException - for a bad location within a document model
        IllegalArgumentException - for an invalid direction