001    /* GlyphView.java -- A view to render styled text
002       Copyright (C) 2005  Free Software Foundation, Inc.
003    
004    This file is part of GNU Classpath.
005    
006    GNU Classpath is free software; you can redistribute it and/or modify
007    it under the terms of the GNU General Public License as published by
008    the Free Software Foundation; either version 2, or (at your option)
009    any later version.
010    
011    GNU Classpath is distributed in the hope that it will be useful, but
012    WITHOUT ANY WARRANTY; without even the implied warranty of
013    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014    General Public License for more details.
015    
016    You should have received a copy of the GNU General Public License
017    along with GNU Classpath; see the file COPYING.  If not, write to the
018    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019    02110-1301 USA.
020    
021    Linking this library statically or dynamically with other modules is
022    making a combined work based on this library.  Thus, the terms and
023    conditions of the GNU General Public License cover the whole
024    combination.
025    
026    As a special exception, the copyright holders of this library give you
027    permission to link this library with independent modules to produce an
028    executable, regardless of the license terms of these independent
029    modules, and to copy and distribute the resulting executable under
030    terms of your choice, provided that you also meet, for each linked
031    independent module, the terms and conditions of the license of that
032    module.  An independent module is a module which is not derived from
033    or based on this library.  If you modify this library, you may extend
034    this exception to your version of the library, but you are not
035    obligated to do so.  If you do not wish to do so, delete this
036    exception statement from your version. */
037    
038    
039    package javax.swing.text;
040    
041    import gnu.classpath.SystemProperties;
042    
043    import java.awt.Color;
044    import java.awt.Container;
045    import java.awt.Font;
046    import java.awt.FontMetrics;
047    import java.awt.Graphics;
048    import java.awt.Graphics2D;
049    import java.awt.Rectangle;
050    import java.awt.Shape;
051    import java.awt.Toolkit;
052    import java.awt.font.FontRenderContext;
053    import java.awt.font.TextHitInfo;
054    import java.awt.font.TextLayout;
055    import java.awt.geom.Rectangle2D;
056    
057    import javax.swing.SwingConstants;
058    import javax.swing.event.DocumentEvent;
059    import javax.swing.text.Position.Bias;
060    
061    /**
062     * Renders a run of styled text. This {@link View} subclass paints the
063     * characters of the <code>Element</code> it is responsible for using
064     * the style information from that <code>Element</code>.
065     *
066     * @author Roman Kennke (roman@kennke.org)
067     */
068    public class GlyphView extends View implements TabableView, Cloneable
069    {
070    
071      /**
072       * An abstract base implementation for a glyph painter for
073       * <code>GlyphView</code>.
074       */
075      public abstract static class GlyphPainter
076      {
077        /**
078         * Creates a new <code>GlyphPainer</code>.
079         */
080        public GlyphPainter()
081        {
082          // Nothing to do here.
083        }
084    
085        /**
086         * Returns the ascent of the font that is used by this glyph painter.
087         *
088         * @param v the glyph view
089         *
090         * @return the ascent of the font that is used by this glyph painter
091         */
092        public abstract float getAscent(GlyphView v);
093    
094        /**
095         * Returns the descent of the font that is used by this glyph painter.
096         *
097         * @param v the glyph view
098         *
099         * @return the descent of the font that is used by this glyph painter
100         */
101        public abstract float getDescent(GlyphView v);
102    
103        /**
104         * Returns the full height of the rendered text.
105         *
106         * @return the full height of the rendered text
107         */
108        public abstract float getHeight(GlyphView view);
109    
110        /**
111         * Determines the model offset, so that the text between <code>p0</code>
112         * and this offset fits within the span starting at <code>x</code> with
113         * the length of <code>len</code>. 
114         *
115         * @param v the glyph view
116         * @param p0 the starting offset in the model
117         * @param x the start location in the view
118         * @param len the length of the span in the view
119         */
120        public abstract int getBoundedPosition(GlyphView v, int p0, float x,
121                                               float len);
122    
123        /**
124         * Paints the glyphs.
125         *
126         * @param view the glyph view to paint
127         * @param g the graphics context to use for painting
128         * @param a the allocation of the glyph view
129         * @param p0 the start position (in the model) from which to paint
130         * @param p1 the end position (in the model) to which to paint
131         */
132        public abstract void paint(GlyphView view, Graphics g, Shape a, int p0,
133                                   int p1);
134    
135        /**
136         * Maps a position in the document into the coordinate space of the View.
137         * The output rectangle usually reflects the font height but has a width
138         * of zero.
139         *
140         * @param view the glyph view
141         * @param pos the position of the character in the model
142         * @param a the area that is occupied by the view
143         * @param b either {@link Position.Bias#Forward} or
144         *        {@link Position.Bias#Backward} depending on the preferred
145         *        direction bias. If <code>null</code> this defaults to
146         *        <code>Position.Bias.Forward</code>
147         *
148         * @return a rectangle that gives the location of the document position
149         *         inside the view coordinate space
150         *
151         * @throws BadLocationException if <code>pos</code> is invalid
152         * @throws IllegalArgumentException if b is not one of the above listed
153         *         valid values
154         */
155        public abstract Shape modelToView(GlyphView view, int pos, Position.Bias b,
156                                          Shape a)
157          throws BadLocationException;
158    
159        /**
160         * Maps a visual position into a document location.
161         *
162         * @param v the glyph view
163         * @param x the X coordinate of the visual position
164         * @param y the Y coordinate of the visual position
165         * @param a the allocated region
166         * @param biasRet filled with the bias of the model location on method exit
167         *
168         * @return the model location that represents the specified view location
169         */
170        public abstract int viewToModel(GlyphView v, float x, float y, Shape a,
171                                        Position.Bias[] biasRet);
172    
173        /**
174         * Determine the span of the glyphs from location <code>p0</code> to
175         * location <code>p1</code>. If <code>te</code> is not <code>null</code>,
176         * then TABs are expanded using this <code>TabExpander</code>.
177         * The parameter <code>x</code> is the location at which the view is
178         * located (this is important when using TAB expansion).
179         *
180         * @param view the glyph view
181         * @param p0 the starting location in the document model
182         * @param p1 the end location in the document model
183         * @param te the tab expander to use
184         * @param x the location at which the view is located
185         *
186         * @return the span of the glyphs from location <code>p0</code> to
187         *         location <code>p1</code>, possibly using TAB expansion
188         */
189        public abstract float getSpan(GlyphView view, int p0, int p1,
190                                      TabExpander te, float x);
191    
192    
193        /**
194         * Returns the model location that should be used to place a caret when
195         * moving the caret through the document.
196         *
197         * @param v the glyph view
198         * @param pos the current model location
199         * @param b the bias for <code>p</code>
200         * @param a the allocated region for the glyph view
201         * @param direction the direction from the current position; Must be one of
202         *        {@link SwingConstants#EAST}, {@link SwingConstants#WEST},
203         *        {@link SwingConstants#NORTH} or {@link SwingConstants#SOUTH}
204         * @param biasRet filled with the bias of the resulting location when method
205         *        returns
206         *
207         * @return the location within the document that should be used to place the
208         *         caret when moving the caret around the document
209         *
210         * @throws BadLocationException if <code>pos</code> is an invalid model
211         *         location
212         * @throws IllegalArgumentException if <code>d</code> is invalid
213         */
214        public int getNextVisualPositionFrom(GlyphView v, int pos, Position.Bias b,
215                                             Shape a, int direction,
216                                             Position.Bias[] biasRet)
217          throws BadLocationException
218    
219        {
220          int result = pos;
221          switch (direction)
222          {
223            case SwingConstants.EAST:
224              result = pos + 1;
225              break;
226            case SwingConstants.WEST:
227              result = pos - 1;
228              break;
229            case SwingConstants.NORTH:
230            case SwingConstants.SOUTH:
231            default:
232              // This should be handled in enclosing view, since the glyph view
233              // does not layout vertically.
234              break;
235          }
236          return result;
237        }
238    
239        /**
240         * Returns a painter that can be used to render the specified glyph view.
241         * If this glyph painter is stateful, then it should return a new instance.
242         * However, if this painter is stateless it should return itself. The
243         * default behaviour is to return itself.
244         *
245         * @param v the glyph view for which to create a painter
246         * @param p0 the start offset of the rendered area
247         * @param p1 the end offset of the rendered area
248         *
249         * @return a painter that can be used to render the specified glyph view
250         */
251        public GlyphPainter getPainter(GlyphView v, int p0, int p1)
252        {
253          return this;
254        }
255      }
256    
257      /**
258       * A GlyphPainter implementation based on TextLayout. This should give
259       * better performance in Java2D environments.
260       */
261      private static class J2DGlyphPainter
262        extends GlyphPainter
263      {
264    
265        /**
266         * The text layout.
267         */
268        TextLayout textLayout;
269    
270        /**
271         * Creates a new J2DGlyphPainter.
272         *
273         * @param str the string
274         * @param font the font
275         * @param frc the font render context
276         */
277        J2DGlyphPainter(String str, Font font, FontRenderContext frc)
278        {
279          textLayout = new TextLayout(str, font, frc);
280        }
281    
282        /**
283         * Returns null so that GlyphView.checkPainter() creates a new instance.
284         */
285        public GlyphPainter getPainter(GlyphView v, int p0, int p1)
286        {
287          return null;
288        }
289    
290        /**
291         * Delegates to the text layout.
292         */
293        public float getAscent(GlyphView v)
294        {
295          return textLayout.getAscent();
296        }
297    
298        /**
299         * Delegates to the text layout.
300         */
301        public int getBoundedPosition(GlyphView v, int p0, float x, float len)
302        {
303          int pos;
304          TextHitInfo hit = textLayout.hitTestChar(len, 0);
305          if (hit.getCharIndex() == -1 && ! textLayout.isLeftToRight())
306            pos = v.getEndOffset();
307          else
308            {
309              pos = hit.isLeadingEdge() ? hit.getInsertionIndex()
310                                        : hit.getInsertionIndex() - 1;
311              pos += v.getStartOffset();
312            }
313          return pos;
314        }
315    
316        /**
317         * Delegates to the text layout.
318         */
319        public float getDescent(GlyphView v)
320        {
321          return textLayout.getDescent();
322        }
323    
324        /**
325         * Delegates to the text layout.
326         */
327        public float getHeight(GlyphView view)
328        {
329          return textLayout.getAscent() + textLayout.getDescent()
330                 + textLayout.getLeading();
331        }
332    
333        /**
334         * Delegates to the text layout.
335         */
336        public float getSpan(GlyphView v, int p0, int p1, TabExpander te, float x)
337        {
338          float span;
339          if (p0 == v.getStartOffset() && p1 == v.getEndOffset())
340            span = textLayout.getAdvance();
341          else
342            {
343              int start = v.getStartOffset();
344              int i0 = p0 - start;
345              int i1 = p1 - start;
346              TextHitInfo hit0 = TextHitInfo.afterOffset(i0);
347              TextHitInfo hit1 = TextHitInfo.afterOffset(i1);
348              float x0 = textLayout.getCaretInfo(hit0)[0];
349              float x1 = textLayout.getCaretInfo(hit1)[0];
350              span = Math.abs(x1 - x0);
351            }
352          return span;
353        }
354    
355        /**
356         * Delegates to the text layout.
357         */
358        public Shape modelToView(GlyphView v, int pos, Bias b, Shape a)
359          throws BadLocationException
360        {
361          int offs = pos - v.getStartOffset();
362          // Create copy here to protect original shape.
363          Rectangle2D bounds = a.getBounds2D();
364          TextHitInfo hit =
365            b == Position.Bias.Forward ? TextHitInfo.afterOffset(offs)
366                                       : TextHitInfo.beforeOffset(offs);
367          float[] loc = textLayout.getCaretInfo(hit);
368          bounds.setRect(bounds.getX() + loc[0], bounds.getY(), 1,
369                         bounds.getHeight());
370          return bounds;
371        }
372    
373        /**
374         * Delegates to the text layout.
375         */
376        public void paint(GlyphView view, Graphics g, Shape a, int p0, int p1)
377        {
378          // Can't paint this with plain graphics.
379          if (g instanceof Graphics2D)
380            {
381              Graphics2D g2d = (Graphics2D) g;
382              Rectangle2D b = a instanceof Rectangle2D ? (Rectangle2D) a
383                                                       : a.getBounds2D();
384              float x = (float) b.getX();
385              float y = (float) b.getY() + textLayout.getAscent()
386                        + textLayout.getLeading();
387              // TODO: Try if clipping makes things faster for narrow views.
388              textLayout.draw(g2d, x, y);
389            }
390        }
391    
392        /**
393         * Delegates to the text layout.
394         */
395        public int viewToModel(GlyphView v, float x, float y, Shape a,
396                               Bias[] biasRet)
397        {
398          Rectangle2D bounds = a instanceof Rectangle2D ? (Rectangle2D) a
399                                                        : a.getBounds2D();
400          TextHitInfo hit = textLayout.hitTestChar(x - (float) bounds.getX(), 0);
401          int pos = hit.getInsertionIndex();
402          biasRet[0] = hit.isLeadingEdge() ? Position.Bias.Forward
403                                           : Position.Bias.Backward;
404          return pos + v.getStartOffset();
405        }
406        
407      }
408    
409      /**
410       * The default <code>GlyphPainter</code> used in <code>GlyphView</code>.
411       */
412      static class DefaultGlyphPainter extends GlyphPainter
413      {
414        FontMetrics fontMetrics;
415    
416        /**
417         * Returns the full height of the rendered text.
418         *
419         * @return the full height of the rendered text
420         */
421        public float getHeight(GlyphView view)
422        {
423          updateFontMetrics(view);
424          float height = fontMetrics.getHeight();
425          return height;
426        }
427        
428        /**
429         * Paints the glyphs.
430         *
431         * @param view the glyph view to paint
432         * @param g the graphics context to use for painting
433         * @param a the allocation of the glyph view
434         * @param p0 the start position (in the model) from which to paint
435         * @param p1 the end position (in the model) to which to paint
436         */
437        public void paint(GlyphView view, Graphics g, Shape a, int p0,
438                          int p1)
439        {
440          updateFontMetrics(view);
441          Rectangle r = a instanceof Rectangle ? (Rectangle) a : a.getBounds();
442          TabExpander tabEx = view.getTabExpander();
443          Segment txt = view.getText(p0, p1);
444    
445          // Find out the X location at which we have to paint.
446          int x = r.x;
447          int p = view.getStartOffset();
448          if (p != p0)
449            {
450              int width = Utilities.getTabbedTextWidth(txt, fontMetrics,x, tabEx,
451                                                       p);
452              x += width;
453            }
454          // Find out Y location.
455          int y = r.y + fontMetrics.getHeight() - fontMetrics.getDescent();
456    
457          // Render the thing.
458          g.setFont(fontMetrics.getFont());
459          Utilities.drawTabbedText(txt, x, y, g, tabEx, p0);
460    
461        }
462    
463        /**
464         * Maps a position in the document into the coordinate space of the View.
465         * The output rectangle usually reflects the font height but has a width
466         * of zero.
467         *
468         * @param view the glyph view
469         * @param pos the position of the character in the model
470         * @param a the area that is occupied by the view
471         * @param b either {@link Position.Bias#Forward} or
472         *        {@link Position.Bias#Backward} depending on the preferred
473         *        direction bias. If <code>null</code> this defaults to
474         *        <code>Position.Bias.Forward</code>
475         *
476         * @return a rectangle that gives the location of the document position
477         *         inside the view coordinate space
478         *
479         * @throws BadLocationException if <code>pos</code> is invalid
480         * @throws IllegalArgumentException if b is not one of the above listed
481         *         valid values
482         */
483        public Shape modelToView(GlyphView view, int pos, Position.Bias b,
484                                 Shape a)
485          throws BadLocationException
486        {
487          updateFontMetrics(view);
488          Element el = view.getElement();
489          Segment txt = view.getText(el.getStartOffset(), pos);
490          Rectangle bounds = a instanceof Rectangle ? (Rectangle) a
491                                                    : a.getBounds();
492          TabExpander expander = view.getTabExpander();
493          int width = Utilities.getTabbedTextWidth(txt, fontMetrics, bounds.x,
494                                                   expander,
495                                                   view.getStartOffset());
496          int height = fontMetrics.getHeight();
497          Rectangle result = new Rectangle(bounds.x + width, bounds.y,
498                                           0, height);
499          return result;
500        }
501    
502        /**
503         * Determine the span of the glyphs from location <code>p0</code> to
504         * location <code>p1</code>. If <code>te</code> is not <code>null</code>,
505         * then TABs are expanded using this <code>TabExpander</code>.
506         * The parameter <code>x</code> is the location at which the view is
507         * located (this is important when using TAB expansion).
508         *
509         * @param view the glyph view
510         * @param p0 the starting location in the document model
511         * @param p1 the end location in the document model
512         * @param te the tab expander to use
513         * @param x the location at which the view is located
514         *
515         * @return the span of the glyphs from location <code>p0</code> to
516         *         location <code>p1</code>, possibly using TAB expansion
517         */
518        public float getSpan(GlyphView view, int p0, int p1,
519                             TabExpander te, float x)
520        {
521          updateFontMetrics(view);
522          Segment txt = view.getText(p0, p1);
523          int span = Utilities.getTabbedTextWidth(txt, fontMetrics, (int) x, te,
524                                                  p0);
525          return span;
526        }
527    
528        /**
529         * Returns the ascent of the text run that is rendered by this
530         * <code>GlyphPainter</code>.
531         *
532         * @param v the glyph view
533         *
534         * @return the ascent of the text run that is rendered by this
535         *         <code>GlyphPainter</code>
536         *
537         * @see FontMetrics#getAscent()
538         */
539        public float getAscent(GlyphView v)
540        {
541          updateFontMetrics(v);
542          return fontMetrics.getAscent();
543        }
544    
545        /**
546         * Returns the descent of the text run that is rendered by this
547         * <code>GlyphPainter</code>.
548         *
549         * @param v the glyph view
550         *
551         * @return the descent of the text run that is rendered by this
552         *         <code>GlyphPainter</code>
553         *
554         * @see FontMetrics#getDescent()
555         */
556        public float getDescent(GlyphView v)
557        {
558          updateFontMetrics(v);
559          return fontMetrics.getDescent();
560        }
561    
562        /**
563         * Determines the model offset, so that the text between <code>p0</code>
564         * and this offset fits within the span starting at <code>x</code> with
565         * the length of <code>len</code>. 
566         *
567         * @param v the glyph view
568         * @param p0 the starting offset in the model
569         * @param x the start location in the view
570         * @param len the length of the span in the view
571         */
572        public int getBoundedPosition(GlyphView v, int p0, float x, float len)
573        {
574          updateFontMetrics(v);
575          TabExpander te = v.getTabExpander();
576          Segment txt = v.getText(p0, v.getEndOffset());
577          int pos = Utilities.getTabbedTextOffset(txt, fontMetrics, (int) x,
578                                                  (int) (x + len), te, p0, false);
579          return pos + p0;
580        }
581    
582        /**
583         * Maps a visual position into a document location.
584         *
585         * @param v the glyph view
586         * @param x the X coordinate of the visual position
587         * @param y the Y coordinate of the visual position
588         * @param a the allocated region
589         * @param biasRet filled with the bias of the model location on method exit
590         *
591         * @return the model location that represents the specified view location
592         */
593        public int viewToModel(GlyphView v, float x, float y, Shape a,
594                               Bias[] biasRet)
595        {
596          Rectangle r = a instanceof Rectangle ? (Rectangle) a : a.getBounds();
597          int p0 = v.getStartOffset();
598          int p1 = v.getEndOffset();
599          TabExpander te = v.getTabExpander();
600          Segment s = v.getText(p0, p1);
601          int offset = Utilities.getTabbedTextOffset(s, fontMetrics, r.x, (int) x,
602                                                     te, p0);
603          int ret = p0 + offset;
604          if (ret == p1)
605            ret--;
606          biasRet[0] = Position.Bias.Forward;
607          return ret;
608        }
609    
610        private void updateFontMetrics(GlyphView v)
611        {
612          Font font = v.getFont();
613          if (fontMetrics == null || ! font.equals(fontMetrics.getFont()))
614            {
615              Container c = v.getContainer();
616              FontMetrics fm;
617              if (c != null)
618                fm = c.getFontMetrics(font);
619              else
620                fm = Toolkit.getDefaultToolkit().getFontMetrics(font);
621              fontMetrics = fm;
622            }
623        }
624      }
625    
626      /**
627       * The GlyphPainer used for painting the glyphs.
628       */
629      GlyphPainter glyphPainter;
630    
631      /**
632       * The start offset within the document for this view.
633       */
634      private int offset;
635    
636      /**
637       * The end offset within the document for this view.
638       */
639      private int length;
640    
641      /**
642       * The x location against which the tab expansion is done.
643       */
644      private float tabX;
645    
646      /**
647       * The tab expander that is used in this view.
648       */
649      private TabExpander tabExpander;
650    
651      /**
652       * Creates a new <code>GlyphView</code> for the given <code>Element</code>.
653       *
654       * @param element the element that is rendered by this GlyphView
655       */
656      public GlyphView(Element element)
657      {
658        super(element);
659        offset = 0;
660        length = 0;
661      }
662    
663      /**
664       * Returns the <code>GlyphPainter</code> that is used by this
665       * <code>GlyphView</code>. If no <code>GlyphPainer</code> has been installed
666       * <code>null</code> is returned.
667       *
668       * @return the glyph painter that is used by this
669       *         glyph view or <code>null</code> if no glyph painter has been
670       *         installed
671       */
672      public GlyphPainter getGlyphPainter()
673      {
674        return glyphPainter;
675      }
676    
677      /**
678       * Sets the {@link GlyphPainter} to be used for this <code>GlyphView</code>.
679       *
680       * @param painter the glyph painter to be used for this glyph view
681       */
682      public void setGlyphPainter(GlyphPainter painter)
683      {
684        glyphPainter = painter;
685      }
686    
687      /**
688       * Checks if a <code>GlyphPainer</code> is installed. If this is not the
689       * case, a default painter is installed.
690       */
691      protected void checkPainter()
692      {
693        if (glyphPainter == null)
694          {
695            if ("true".equals(
696                     SystemProperties.getProperty("gnu.javax.swing.noGraphics2D")))
697              {
698                glyphPainter = new DefaultGlyphPainter();
699              }
700            else
701              {
702                Segment s = getText(getStartOffset(), getEndOffset());
703                glyphPainter = new J2DGlyphPainter(s.toString(), getFont(),
704                                                   new FontRenderContext(null,
705                                                                         false,
706                                                                         false));
707              }
708          }
709      }
710    
711      /**
712       * Renders the <code>Element</code> that is associated with this
713       * <code>View</code>.
714       *
715       * @param g the <code>Graphics</code> context to render to
716       * @param a the allocated region for the <code>Element</code>
717       */
718      public void paint(Graphics g, Shape a)
719      {
720        checkPainter();
721        int p0 = getStartOffset();
722        int p1 = getEndOffset();
723    
724        Rectangle r = a instanceof Rectangle ? (Rectangle) a : a.getBounds();
725        Container c = getContainer();
726    
727        Color fg = getForeground();
728        JTextComponent tc = null;
729        if (c instanceof JTextComponent)
730          {
731            tc = (JTextComponent) c;
732            if (! tc.isEnabled())
733              fg = tc.getDisabledTextColor();
734          }
735        Color bg = getBackground();
736        if (bg != null)
737          {
738            g.setColor(bg);
739            g.fillRect(r.x, r.y, r.width, r.height);
740          }
741    
742        
743        // Paint layered highlights if there are any.
744        if (tc != null)
745          {
746            Highlighter h = tc.getHighlighter();
747            if (h instanceof LayeredHighlighter)
748              {
749                LayeredHighlighter lh = (LayeredHighlighter) h;
750                lh.paintLayeredHighlights(g, p0, p1, a, tc, this);
751              }
752          }
753    
754        g.setColor(fg);
755        glyphPainter.paint(this, g, a, p0, p1);
756        boolean underline = isUnderline();
757        boolean striked = isStrikeThrough();
758        if (underline || striked)
759          {
760            View parent = getParent();
761            // X coordinate.
762            if (parent != null && parent.getEndOffset() == p1)
763              {
764                // Strip whitespace.
765                Segment s = getText(p0, p1);
766                while (s.count > 0 && Character.isWhitespace(s.array[s.count - 1]))
767                  {
768                    p1--;
769                    s.count--;
770                  }
771              }
772            int x0 = r.x;
773            int p = getStartOffset();
774            TabExpander tabEx = getTabExpander();
775            if (p != p0)
776              x0 += (int) glyphPainter.getSpan(this, p, p0, tabEx, x0);
777            int x1 = x0 + (int) glyphPainter.getSpan(this, p0, p1, tabEx, x0);
778            // Y coordinate.
779            int y = r.y + r.height - (int) glyphPainter.getDescent(this);
780            if (underline)
781              {
782                int yTmp = y;
783                yTmp += 1;
784                g.drawLine(x0, yTmp, x1, yTmp);
785              }
786            if (striked)
787              {
788                int yTmp = y;
789                yTmp -= (int) glyphPainter.getAscent(this);
790                g.drawLine(x0, yTmp, x1, yTmp);
791              }
792          }
793      }
794    
795    
796      /**
797       * Returns the preferred span of the content managed by this
798       * <code>View</code> along the specified <code>axis</code>.
799       *
800       * @param axis the axis
801       *
802       * @return the preferred span of this <code>View</code>.
803       */
804      public float getPreferredSpan(int axis)
805      {
806        float span = 0;
807        checkPainter();
808        GlyphPainter painter = getGlyphPainter();
809        switch (axis)
810          {
811          case X_AXIS:
812            TabExpander tabEx = null;
813            View parent = getParent();
814            if (parent instanceof TabExpander)
815              tabEx = (TabExpander) parent;
816            span = painter.getSpan(this, getStartOffset(), getEndOffset(),
817                                   tabEx, 0.F);
818            break;
819          case Y_AXIS:
820            span = painter.getHeight(this);
821            if (isSuperscript())
822              span += span / 3;
823            break;
824          default:
825            throw new IllegalArgumentException("Illegal axis");
826          }
827        return span;
828      }
829    
830      /**
831       * Maps a position in the document into the coordinate space of the View.
832       * The output rectangle usually reflects the font height but has a width
833       * of zero.
834       *
835       * @param pos the position of the character in the model
836       * @param a the area that is occupied by the view
837       * @param b either {@link Position.Bias#Forward} or
838       *        {@link Position.Bias#Backward} depending on the preferred
839       *        direction bias. If <code>null</code> this defaults to
840       *        <code>Position.Bias.Forward</code>
841       *
842       * @return a rectangle that gives the location of the document position
843       *         inside the view coordinate space
844       *
845       * @throws BadLocationException if <code>pos</code> is invalid
846       * @throws IllegalArgumentException if b is not one of the above listed
847       *         valid values
848       */
849      public Shape modelToView(int pos, Shape a, Position.Bias b)
850        throws BadLocationException
851      {
852        GlyphPainter p = getGlyphPainter();
853        return p.modelToView(this, pos, b, a);
854      }
855    
856      /**
857       * Maps coordinates from the <code>View</code>'s space into a position
858       * in the document model.
859       *
860       * @param x the x coordinate in the view space
861       * @param y the y coordinate in the view space
862       * @param a the allocation of this <code>View</code>
863       * @param b the bias to use
864       *
865       * @return the position in the document that corresponds to the screen
866       *         coordinates <code>x, y</code>
867       */
868      public int viewToModel(float x, float y, Shape a, Position.Bias[] b)
869      {
870        checkPainter();
871        GlyphPainter painter = getGlyphPainter();
872        return painter.viewToModel(this, x, y, a, b);
873      }
874    
875      /**
876       * Return the {@link TabExpander} to use.
877       *
878       * @return the {@link TabExpander} to use
879       */
880      public TabExpander getTabExpander()
881      {
882        return tabExpander;
883      }
884    
885      /**
886       * Returns the preferred span of this view for tab expansion.
887       *
888       * @param x the location of the view
889       * @param te the tab expander to use
890       *
891       * @return the preferred span of this view for tab expansion
892       */
893      public float getTabbedSpan(float x, TabExpander te)
894      {
895        checkPainter();
896        TabExpander old = tabExpander;
897        tabExpander = te;
898        if (tabExpander != old)
899          {
900            // Changing the tab expander will lead to a relayout in the X_AXIS.
901            preferenceChanged(null, true, false);
902          }
903        tabX = x;
904        return getGlyphPainter().getSpan(this, getStartOffset(),
905                                         getEndOffset(), tabExpander, x);
906      }
907    
908      /**
909       * Returns the span of a portion of the view. This is used in TAB expansion
910       * for fragments that don't contain TABs.
911       *
912       * @param p0 the start index
913       * @param p1 the end index
914       *
915       * @return the span of the specified portion of the view
916       */
917      public float getPartialSpan(int p0, int p1)
918      {
919        checkPainter();
920        return glyphPainter.getSpan(this, p0, p1, tabExpander, tabX);
921      }
922    
923      /**
924       * Returns the start offset in the document model of the portion
925       * of text that this view is responsible for.
926       *
927       * @return the start offset in the document model of the portion
928       *         of text that this view is responsible for
929       */
930      public int getStartOffset()
931      {
932        Element el = getElement();
933        int offs = el.getStartOffset();
934        if (length > 0)
935          offs += offset;
936        return offs;
937      }
938    
939      /**
940       * Returns the end offset in the document model of the portion
941       * of text that this view is responsible for.
942       *
943       * @return the end offset in the document model of the portion
944       *         of text that this view is responsible for
945       */
946      public int getEndOffset()
947      {
948        Element el = getElement();
949        int offs;
950        if (length > 0)
951          offs = el.getStartOffset() + offset + length;
952        else
953          offs = el.getEndOffset();
954        return offs;
955      }
956    
957      private Segment cached = new Segment();
958    
959      /**
960       * Returns the text segment that this view is responsible for.
961       *
962       * @param p0 the start index in the document model
963       * @param p1 the end index in the document model
964       *
965       * @return the text segment that this view is responsible for
966       */
967      public Segment getText(int p0, int p1)
968      {
969        try
970          {
971            getDocument().getText(p0, p1 - p0, cached);
972          }
973        catch (BadLocationException ex)
974          {
975            AssertionError ae;
976            ae = new AssertionError("BadLocationException should not be "
977                                    + "thrown here. p0 = " + p0 + ", p1 = " + p1);
978            ae.initCause(ex);
979            throw ae;
980          }
981    
982        return cached;
983      }
984    
985      /**
986       * Returns the font for the text run for which this <code>GlyphView</code>
987       * is responsible.
988       *
989       * @return the font for the text run for which this <code>GlyphView</code>
990       *         is responsible
991       */
992      public Font getFont()
993      {
994        Document doc = getDocument();
995        Font font = null;
996        if (doc instanceof StyledDocument)
997          {
998            StyledDocument styledDoc = (StyledDocument) doc;
999            font = styledDoc.getFont(getAttributes());
1000          }
1001        else
1002          {
1003            Container c = getContainer();
1004            if (c != null)
1005              font = c.getFont();
1006          }
1007        return font;
1008      }
1009    
1010      /**
1011       * Returns the foreground color which should be used to paint the text.
1012       * This is fetched from the associated element's text attributes using
1013       * {@link StyleConstants#getForeground}.
1014       *
1015       * @return the foreground color which should be used to paint the text
1016       */
1017      public Color getForeground()
1018      {
1019        Element el = getElement();
1020        AttributeSet atts = el.getAttributes();
1021        return StyleConstants.getForeground(atts);
1022      }
1023    
1024      /**
1025       * Returns the background color which should be used to paint the text.
1026       * This is fetched from the associated element's text attributes using
1027       * {@link StyleConstants#getBackground}.
1028       *
1029       * @return the background color which should be used to paint the text
1030       */
1031      public Color getBackground()
1032      {
1033        Element el = getElement();
1034        AttributeSet atts = el.getAttributes();
1035        // We cannot use StyleConstants.getBackground() here, because that returns
1036        // BLACK as default (when background == null). What we need is the
1037        // background setting of the text component instead, which is what we get
1038        // when background == null anyway.
1039        return (Color) atts.getAttribute(StyleConstants.Background);
1040      }
1041    
1042      /**
1043       * Determines whether the text should be rendered strike-through or not. This
1044       * is determined using the method
1045       * {@link StyleConstants#isStrikeThrough(AttributeSet)} on the element of
1046       * this view.
1047       *
1048       * @return whether the text should be rendered strike-through or not
1049       */
1050      public boolean isStrikeThrough()
1051      {
1052        Element el = getElement();
1053        AttributeSet atts = el.getAttributes();
1054        return StyleConstants.isStrikeThrough(atts);
1055      }
1056    
1057      /**
1058       * Determines whether the text should be rendered as subscript or not. This
1059       * is determined using the method
1060       * {@link StyleConstants#isSubscript(AttributeSet)} on the element of
1061       * this view.
1062       *
1063       * @return whether the text should be rendered as subscript or not
1064       */
1065      public boolean isSubscript()
1066      {
1067        Element el = getElement();
1068        AttributeSet atts = el.getAttributes();
1069        return StyleConstants.isSubscript(atts);
1070      }
1071    
1072      /**
1073       * Determines whether the text should be rendered as superscript or not. This
1074       * is determined using the method
1075       * {@link StyleConstants#isSuperscript(AttributeSet)} on the element of
1076       * this view.
1077       *
1078       * @return whether the text should be rendered as superscript or not
1079       */
1080      public boolean isSuperscript()
1081      {
1082        Element el = getElement();
1083        AttributeSet atts = el.getAttributes();
1084        return StyleConstants.isSuperscript(atts);
1085      }
1086    
1087      /**
1088       * Determines whether the text should be rendered as underlined or not. This
1089       * is determined using the method
1090       * {@link StyleConstants#isUnderline(AttributeSet)} on the element of
1091       * this view.
1092       *
1093       * @return whether the text should be rendered as underlined or not
1094       */
1095      public boolean isUnderline()
1096      {
1097        Element el = getElement();
1098        AttributeSet atts = el.getAttributes();
1099        return StyleConstants.isUnderline(atts);
1100      }
1101    
1102      /**
1103       * Creates and returns a shallow clone of this GlyphView. This is used by
1104       * the {@link #createFragment} and {@link #breakView} methods.
1105       *
1106       * @return a shallow clone of this GlyphView
1107       */
1108      protected final Object clone()
1109      {
1110        try
1111          {
1112            return super.clone();
1113          }
1114        catch (CloneNotSupportedException ex)
1115          {
1116            AssertionError err = new AssertionError("CloneNotSupportedException "
1117                                                    + "must not be thrown here");
1118            err.initCause(ex);
1119            throw err;
1120          }
1121      }
1122    
1123      /**
1124       * Tries to break the view near the specified view span <code>len</code>.
1125       * The glyph view can only be broken in the X direction. For Y direction it
1126       * returns itself.
1127       *
1128       * @param axis the axis for breaking, may be {@link View#X_AXIS} or
1129       *        {@link View#Y_AXIS}
1130       * @param p0 the model location where the fragment should start
1131       * @param pos the view position along the axis where the fragment starts
1132       * @param len the desired length of the fragment view
1133       *
1134       * @return the fragment view, or <code>this</code> if breaking was not
1135       *         possible
1136       */
1137      public View breakView(int axis, int p0, float pos, float len)
1138      {
1139        View brokenView = this;
1140        if (axis == X_AXIS)
1141          {
1142            checkPainter();
1143            int end = glyphPainter.getBoundedPosition(this, p0, pos, len);
1144            int breakLoc = getBreakLocation(p0, end);
1145            if (breakLoc != -1)
1146              end = breakLoc;
1147            if (p0 != getStartOffset() || end != getEndOffset())
1148              {
1149                brokenView = createFragment(p0, end);
1150                if (brokenView instanceof GlyphView)
1151                  ((GlyphView) brokenView).tabX = pos;
1152              }
1153          }
1154        return brokenView;
1155      }
1156    
1157      /**
1158       * Determines how well the specified view location is suitable for inserting
1159       * a line break. If <code>axis</code> is <code>View.Y_AXIS</code>, then
1160       * this method forwards to the superclass, if <code>axis</code> is
1161       * <code>View.X_AXIS</code> then this method returns
1162       * {@link View#ExcellentBreakWeight} if there is a suitable break location
1163       * (usually whitespace) within the specified view span, or
1164       * {@link View#GoodBreakWeight} if not.
1165       *
1166       * @param axis the axis along which the break weight is requested
1167       * @param pos the starting view location
1168       * @param len the length of the span at which the view should be broken
1169       *
1170       * @return the break weight
1171       */
1172      public int getBreakWeight(int axis, float pos, float len)
1173      {
1174        int weight;
1175        if (axis == Y_AXIS)
1176          weight = super.getBreakWeight(axis, pos, len);
1177        else
1178          {
1179            checkPainter();
1180            int start = getStartOffset();
1181            int end = glyphPainter.getBoundedPosition(this, start, pos, len);
1182            if (end == 0)
1183              weight = BadBreakWeight;
1184            else
1185              {
1186                if (getBreakLocation(start, end) != -1)
1187                  weight = ExcellentBreakWeight;
1188                else
1189                  weight = GoodBreakWeight;
1190              }
1191          }
1192        return weight;
1193      }
1194    
1195      private int getBreakLocation(int start, int end)
1196      {
1197        int loc = -1;
1198        Segment s = getText(start, end);
1199        for (char c = s.last(); c != Segment.DONE && loc == -1; c = s.previous())
1200          {
1201            if (Character.isWhitespace(c))
1202              {
1203                loc = s.getIndex() - s.getBeginIndex() + 1 + start;
1204              }
1205          }
1206        return loc;
1207      }
1208    
1209      /**
1210       * Receives notification that some text attributes have changed within the
1211       * text fragment that this view is responsible for. This calls
1212       * {@link View#preferenceChanged(View, boolean, boolean)} on the parent for
1213       * both width and height.
1214       *
1215       * @param e the document event describing the change; not used here
1216       * @param a the view allocation on screen; not used here
1217       * @param vf the view factory; not used here
1218       */
1219      public void changedUpdate(DocumentEvent e, Shape a, ViewFactory vf)
1220      {
1221        preferenceChanged(null, true, true);
1222      }
1223    
1224      /**
1225       * Receives notification that some text has been inserted within the
1226       * text fragment that this view is responsible for. This calls
1227       * {@link View#preferenceChanged(View, boolean, boolean)} for the
1228       * direction in which the glyphs are rendered.
1229       *
1230       * @param e the document event describing the change; not used here
1231       * @param a the view allocation on screen; not used here
1232       * @param vf the view factory; not used here
1233       */
1234      public void insertUpdate(DocumentEvent e, Shape a, ViewFactory vf)
1235      {
1236        preferenceChanged(null, true, false);
1237      }
1238    
1239      /**
1240       * Receives notification that some text has been removed within the
1241       * text fragment that this view is responsible for. This calls
1242       * {@link View#preferenceChanged(View, boolean, boolean)} on the parent for
1243       * width.
1244       *
1245       * @param e the document event describing the change; not used here
1246       * @param a the view allocation on screen; not used here
1247       * @param vf the view factory; not used here
1248       */
1249      public void removeUpdate(DocumentEvent e, Shape a, ViewFactory vf)
1250      {
1251        preferenceChanged(null, true, false);
1252      }
1253    
1254      /**
1255       * Creates a fragment view of this view that starts at <code>p0</code> and
1256       * ends at <code>p1</code>.
1257       *
1258       * @param p0 the start location for the fragment view
1259       * @param p1 the end location for the fragment view
1260       *
1261       * @return the fragment view
1262       */
1263      public View createFragment(int p0, int p1)
1264      {
1265        checkPainter();
1266        Element el = getElement();
1267        GlyphView fragment = (GlyphView) clone();
1268        fragment.offset = p0 - el.getStartOffset();
1269        fragment.length = p1 - p0;
1270        fragment.glyphPainter = glyphPainter.getPainter(fragment, p0, p1);
1271        return fragment;
1272      }
1273    
1274      /**
1275       * Returns the alignment of this view along the specified axis. For the Y
1276       * axis this is <code>(height - descent) / height</code> for the used font,
1277       * so that it is aligned along the baseline.
1278       * For the X axis the superclass is called.
1279       */
1280      public float getAlignment(int axis)
1281      {
1282        checkPainter();
1283        float align;
1284        if (axis == Y_AXIS)
1285          {
1286            GlyphPainter painter = getGlyphPainter();
1287            float height = painter.getHeight(this);
1288            float descent = painter.getDescent(this);
1289            float ascent = painter.getAscent(this);
1290            if (isSuperscript())
1291              align = 1.0F;
1292            else if (isSubscript())
1293              align = height > 0 ? (height - (descent + (ascent / 2))) / height
1294                                 : 0;
1295            else
1296              align = height > 0 ? (height - descent) / height : 0;
1297          }
1298        else
1299          align = super.getAlignment(axis);
1300    
1301        return align;
1302      }
1303    
1304      /**
1305       * Returns the model location that should be used to place a caret when
1306       * moving the caret through the document.
1307       *
1308       * @param pos the current model location
1309       * @param bias the bias for <code>p</code>
1310       * @param a the allocated region for the glyph view
1311       * @param direction the direction from the current position; Must be one of
1312       *        {@link SwingConstants#EAST}, {@link SwingConstants#WEST},
1313       *        {@link SwingConstants#NORTH} or {@link SwingConstants#SOUTH}
1314       * @param biasRet filled with the bias of the resulting location when method
1315       *        returns
1316       *
1317       * @return the location within the document that should be used to place the
1318       *         caret when moving the caret around the document
1319       *
1320       * @throws BadLocationException if <code>pos</code> is an invalid model
1321       *         location
1322       * @throws IllegalArgumentException if <code>d</code> is invalid
1323       */
1324      public int getNextVisualPositionFrom(int pos, Position.Bias bias, Shape a,
1325                                           int direction, Position.Bias[] biasRet)
1326        throws BadLocationException
1327      {
1328        checkPainter();
1329        GlyphPainter painter = getGlyphPainter();
1330        return painter.getNextVisualPositionFrom(this, pos, bias, a, direction,
1331                                                 biasRet);
1332      }
1333    }