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package javax.swing.text;

import java.awt.*;


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).


This implementation is intended for operation
under the JDK1.1 API of the Java Platform.
Since the JDK is backward compatible with
JDK1.1 API, this class will also function on
Java 2.  The JDK introduces improved
API for rendering text however, so the GlyphPainter2
is recommended for the DK.

Author: Timothy Prinzing
See Also:
/**
 * 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).
 * <p>
 * This implementation is intended for operation
 * under the JDK1.1 API of the Java Platform.
 * Since the JDK is backward compatible with
 * JDK1.1 API, this class will also function on
 * Java 2.  The JDK introduces improved
 * API for rendering text however, so the GlyphPainter2
 * is recommended for the DK.
 *
 * @author  Timothy Prinzing
 * @see GlyphView
 */
class GlyphPainter1 extends GlyphView.GlyphPainter {

    
Determine the span the glyphs given a start location
(for tab expansion).

/**
     * Determine the span the glyphs given a start location
     * (for tab expansion).
     */
    public float getSpan(GlyphView v, int p0, int p1,
                         TabExpander e, float x) {
        sync(v);
        Segment text = v.getText(p0, p1);
        int[] justificationData = getJustificationData(v);

        int width = Utilities.getTabbedTextWidth(v, text, metrics, (int)x, e, p0,
                                                 justificationData);
        SegmentCache.releaseSharedSegment(text);
        return width;
    }

    public float getHeight(GlyphView v) {
        sync(v);
        return metrics.getHeight();
    }

    
Fetches the ascent above the baseline for the glyphs
corresponding to the given range in the model.

/**
     * Fetches the ascent above the baseline for the glyphs
     * corresponding to the given range in the model.
     */
    public float getAscent(GlyphView v) {
        sync(v);
        return metrics.getAscent();
    }

    
Fetches the descent below the baseline for the glyphs
corresponding to the given range in the model.

/**
     * Fetches the descent below the baseline for the glyphs
     * corresponding to the given range in the model.
     */
    public float getDescent(GlyphView v) {
        sync(v);
        return metrics.getDescent();
    }

    
Paints the glyphs representing the given range.

/**
     * Paints the glyphs representing the given range.
     */
    public void paint(GlyphView v, Graphics g, Shape a, int p0, int p1) {
        sync(v);
        Segment text;
        TabExpander expander = v.getTabExpander();
        Rectangle alloc = (a instanceof Rectangle) ? (Rectangle)a : a.getBounds();

        // determine the x coordinate to render the glyphs
        float x = alloc.x;
        int p = v.getStartOffset();
        int[] justificationData = getJustificationData(v);
        if (p != p0) {
            text = v.getText(p, p0);
            float width = Utilities.getTabbedTextWidth(v, text, metrics, x,
                                                       expander, p,
                                                       justificationData);
            x += width;
            SegmentCache.releaseSharedSegment(text);
        }

        // determine the y coordinate to render the glyphs
        float y = alloc.y + metrics.getHeight() - metrics.getDescent();

        // render the glyphs
        text = v.getText(p0, p1);
        g.setFont(metrics.getFont());

        Utilities.drawTabbedText(v, text, x, y, g, expander,p0,
                                 justificationData, true);
        SegmentCache.releaseSharedSegment(text);
    }

    public Shape modelToView(GlyphView v, int pos, Position.Bias bias,
                             Shape a) throws BadLocationException {

        sync(v);
        Rectangle alloc = (a instanceof Rectangle) ? (Rectangle)a : a.getBounds();
        int p0 = v.getStartOffset();
        int p1 = v.getEndOffset();
        TabExpander expander = v.getTabExpander();
        Segment text;

        if(pos == p1) {
            // The caller of this is left to right and borders a right to
            // left view, return our end location.
            return new Rectangle(alloc.x + alloc.width, alloc.y, 0,
                                 metrics.getHeight());
        }
        if ((pos >= p0) && (pos <= p1)) {
            // determine range to the left of the position
            text = v.getText(p0, pos);
            int[] justificationData = getJustificationData(v);
            int width = Utilities.getTabbedTextWidth(v, text, metrics, alloc.x, expander, p0,
                                                     justificationData);
            SegmentCache.releaseSharedSegment(text);
            return new Rectangle(alloc.x + width, alloc.y, 0, metrics.getHeight());
        }
        throw new BadLocationException("modelToView - can't convert", p1);
    }

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

Params:
  • v – the view containing the view coordinates
  • x – the X coordinate
  • y – the Y coordinate
  • a – the allocated region to render into
  • biasReturn – always returns Position.Bias.Forward
  as the zero-th element of this array
See Also:
Returns:the location within the model that best represents the
 given point in the view
/**
     * Provides a mapping from the view coordinate space to the logical
     * coordinate space of the model.
     *
     * @param v the view containing the view coordinates
     * @param x the X coordinate
     * @param y the Y coordinate
     * @param a the allocated region to render into
     * @param biasReturn always returns <code>Position.Bias.Forward</code>
     *   as the zero-th element of this array
     * @return the location within the model that best represents the
     *  given point in the view
     * @see View#viewToModel
     */
    public int viewToModel(GlyphView v, float x, float y, Shape a,
                           Position.Bias[] biasReturn) {

        sync(v);
        Rectangle alloc = (a instanceof Rectangle) ? (Rectangle)a : a.getBounds();
        int p0 = v.getStartOffset();
        int p1 = v.getEndOffset();
        TabExpander expander = v.getTabExpander();
        Segment text = v.getText(p0, p1);
        int[] justificationData = getJustificationData(v);
        int offs = Utilities.getTabbedTextOffset(v, text, metrics,
                                                 alloc.x, (int) x, expander, p0,
                                                 justificationData);
        SegmentCache.releaseSharedSegment(text);
        int retValue = p0 + offs;
        if(retValue == p1) {
            // No need to return backward bias as GlyphPainter1 is used for
            // ltr text only.
            retValue--;
        }
        biasReturn[0] = Position.Bias.Forward;
        return retValue;
    }

    
Determines the best location (in the model) to break
the given view.
This method attempts to break on a whitespace
location.  If a whitespace location can't be found, the
nearest character location is returned.

Params:
  • v – the view
  • p0 – the location in the model where the
 fragment should start its 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
See Also:
Returns:the model location desired for a break
/**
     * Determines the best location (in the model) to break
     * the given view.
     * This method attempts to break on a whitespace
     * location.  If a whitespace location can't be found, the
     * nearest character location is returned.
     *
     * @param v the view
     * @param p0 the location in the model where the
     *  fragment should start its representation >= 0
     * @param x the graphic location along the axis that the
     *  broken view would occupy >= 0; this may be useful for
     *  things like tab calculations
     * @param len specifies the distance into the view
     *  where a potential break is desired >= 0
     * @return the model location desired for a break
     * @see View#breakView
     */
    public int getBoundedPosition(GlyphView v, int p0, float x, float len) {
        sync(v);
        TabExpander expander = v.getTabExpander();
        Segment s = v.getText(p0, v.getEndOffset());
        int[] justificationData = getJustificationData(v);
        int index = Utilities.getTabbedTextOffset(v, s, metrics, x, (x+len),
                                                  expander, p0, false,
                                                  justificationData, true);
        SegmentCache.releaseSharedSegment(s);
        int p1 = p0 + index;
        return p1;
    }

    @SuppressWarnings("deprecation")
    void sync(GlyphView v) {
        Font f = v.getFont();
        FontMetrics fm = null;
        Container c = v.getContainer();
        if (c != null) {
            fm = c.getFontMetrics(f);
        }
        if ((metrics == null) || (! f.equals(metrics.getFont()))
                || (! metrics.equals(fm))) {
            // fetch a new FontMetrics
            metrics = (c != null) ? fm :
                Toolkit.getDefaultToolkit().getFontMetrics(f);
        }
    }



    
Returns:justificationData from the ParagraphRow this GlyphView is in or null if no justification is needed
/**
     * @return justificationData from the ParagraphRow this GlyphView
     * is in or {@code null} if no justification is needed
     */
    private int[] getJustificationData(GlyphView v) {
        View parent = v.getParent();
        int [] ret = null;
        if (parent instanceof ParagraphView.Row) {
            ParagraphView.Row row = ((ParagraphView.Row) parent);
            ret = row.justificationData;
        }
        return ret;
    }

    // --- variables ---------------------------------------------

    FontMetrics metrics;
}