glyphview.java

gcc的组建

     * The parameter <code>x</code> is the location at which the view is
     * located (this is important when using TAB expansion).
     *
     * @param view the glyph view
     * @param p0 the starting location in the document model
     * @param p1 the end location in the document model
     * @param te the tab expander to use
     * @param x the location at which the view is located
     *
     * @return the span of the glyphs from location <code>p0</code> to
     *         location <code>p1</code>, possibly using TAB expansion
     */
    public float getSpan(GlyphView view, int p0, int p1,
                         TabExpander te, float x)
    {
      Element el = view.getElement();
      Font font = view.getFont();
      FontMetrics fm = Toolkit.getDefaultToolkit().getFontMetrics(font);
      Segment txt = view.getText(p0, p1);
      int span = Utilities.getTabbedTextWidth(txt, fm, (int) x, te, p0);
      return span;
    }

    /**
     * Returns the ascent of the text run that is rendered by this
     * <code>GlyphPainter</code>.
     *
     * @param v the glyph view
     *
     * @return the ascent of the text run that is rendered by this
     *         <code>GlyphPainter</code>
     *
     * @see FontMetrics#getAscent()
     */
    public float getAscent(GlyphView v)
    {
      Font font = v.getFont();
      FontMetrics fm = v.getContainer().getFontMetrics(font);
      return fm.getAscent();
    }

    /**
     * Returns the descent of the text run that is rendered by this
     * <code>GlyphPainter</code>.
     *
     * @param v the glyph view
     *
     * @return the descent of the text run that is rendered by this
     *         <code>GlyphPainter</code>
     *
     * @see FontMetrics#getDescent()
     */
    public float getDescent(GlyphView v)
    {
      Font font = v.getFont();
      FontMetrics fm = v.getContainer().getFontMetrics(font);
      return fm.getDescent();
    }

    /**
     * Determines the model offset, so that the text between <code>p0</code>
     * and this offset fits within the span starting at <code>x</code> with
     * the length of <code>len</code>. 
     *
     * @param v the glyph view
     * @param p0 the starting offset in the model
     * @param x the start location in the view
     * @param len the length of the span in the view
     */
    public int getBoundedPosition(GlyphView v, int p0, float x, float len)
    {
      TabExpander te = v.getTabExpander();
      Segment txt = v.getText(p0, v.getEndOffset());
      Font font = v.getFont();
      FontMetrics fm = v.getContainer().getFontMetrics(font);
      int pos = Utilities.getTabbedTextOffset(txt, fm, (int) x,
                                              (int) (x + len), te, p0, false);
      return pos;
    }

    /**
     * Maps a visual position into a document location.
     *
     * @param v the glyph view
     * @param x the X coordinate of the visual position
     * @param y the Y coordinate of the visual position
     * @param a the allocated region
     * @param biasRet filled with the bias of the model location on method exit
     *
     * @return the model location that represents the specified view location
     */
    public int viewToModel(GlyphView v, float x, float y, Shape a,
                           Bias[] biasRet)
    {
      Rectangle b = a.getBounds();
      int pos = getBoundedPosition(v, v.getStartOffset(), b.x, x - b.x);
      return pos;
    }
  }

  /**
   * The GlyphPainer used for painting the glyphs.
   */
  GlyphPainter glyphPainter;

  /**
   * The start offset within the document for this view.
   */
  int startOffset;

  /**
   * The end offset within the document for this view.
   */
  int endOffset;

  /**
   * Creates a new <code>GlyphView</code> for the given <code>Element</code>.
   *
   * @param element the element that is rendered by this GlyphView
   */
  public GlyphView(Element element)
  {
    super(element);
    startOffset = element.getStartOffset();
    endOffset = element.getEndOffset();
  }

  /**
   * Returns the <code>GlyphPainter</code> that is used by this
   * <code>GlyphView</code>. If no <code>GlyphPainer</code> has been installed
   * <code>null</code> is returned.
   *
   * @return the glyph painter that is used by this
   *         glyph view or <code>null</code> if no glyph painter has been
   *         installed
   */
  public GlyphPainter getGlyphPainter()
  {
    return glyphPainter;
  }

  /**
   * Sets the {@link GlyphPainter} to be used for this <code>GlyphView</code>.
   *
   * @param painter the glyph painter to be used for this glyph view
   */
  public void setGlyphPainter(GlyphPainter painter)
  {
    glyphPainter = painter;
  }

  /**
   * Checks if a <code>GlyphPainer</code> is installed. If this is not the
   * case, a default painter is installed.
   */
  protected void checkPainter()
  {
    if (glyphPainter == null)
      glyphPainter = new DefaultGlyphPainter();
  }

  /**
   * Renders the <code>Element</code> that is associated with this
   * <code>View</code>.
   *
   * @param g the <code>Graphics</code> context to render to
   * @param a the allocated region for the <code>Element</code>
   */
  public void paint(Graphics g, Shape a)
  {
    Element el = getElement();
    checkPainter();
    getGlyphPainter().paint(this, g, a, el.getStartOffset(),
                            el.getEndOffset());
  }


  /**
   * Returns the preferred span of the content managed by this
   * <code>View</code> along the specified <code>axis</code>.
   *
   * @param axis the axis
   *
   * @return the preferred span of this <code>View</code>.
   */
  public float getPreferredSpan(int axis)
  {
    float span = 0;
    checkPainter();
    GlyphPainter painter = getGlyphPainter();
    if (axis == X_AXIS)
      {
        Element el = getElement();
        TabExpander tabEx = null;
        View parent = getParent();
        if (parent instanceof TabExpander)
          tabEx = (TabExpander) parent;
        span = painter.getSpan(this, getStartOffset(), getEndOffset(),
                               tabEx, 0.F);
      }
    else
      span = painter.getHeight(this); 
    return span;
  }

  /**
   * Maps a position in the document into the coordinate space of the View.
   * The output rectangle usually reflects the font height but has a width
   * of zero.
   *
   * @param pos the position of the character in the model
   * @param a the area that is occupied by the view
   * @param b either {@link Position.Bias#Forward} or
   *        {@link Position.Bias#Backward} depending on the preferred
   *        direction bias. If <code>null</code> this defaults to
   *        <code>Position.Bias.Forward</code>
   *
   * @return a rectangle that gives the location of the document position
   *         inside the view coordinate space
   *
   * @throws BadLocationException if <code>pos</code> is invalid
   * @throws IllegalArgumentException if b is not one of the above listed
   *         valid values
   */
  public Shape modelToView(int pos, Shape a, Position.Bias b)
    throws BadLocationException
  {
    GlyphPainter p = getGlyphPainter();
    return p.modelToView(this, pos, b, a);
  }

  /**
   * Maps coordinates from the <code>View</code>'s space into a position
   * in the document model.
   *
   * @param x the x coordinate in the view space
   * @param y the y coordinate in the view space
   * @param a the allocation of this <code>View</code>
   * @param b the bias to use
   *
   * @return the position in the document that corresponds to the screen
   *         coordinates <code>x, y</code>
   */
  public int viewToModel(float x, float y, Shape a, Position.Bias[] b)
  {
    checkPainter();
    GlyphPainter painter = getGlyphPainter();
    return painter.viewToModel(this, x, y, a, b);
  }

  /**
   * Return the {@link TabExpander} to use.
   *
   * @return the {@link TabExpander} to use
   */
  public TabExpander getTabExpander()
  {
    TabExpander te = null;
    View parent = getParent();

    if (parent instanceof TabExpander)
      te = (TabExpander) parent;
    
    return te;
  }

  /**
   * Returns the preferred span of this view for tab expansion.
   *
   * @param x the location of the view
   * @param te the tab expander to use
   *
   * @return the preferred span of this view for tab expansion
   */
  public float getTabbedSpan(float x, TabExpander te)
  {
    Element el = getElement();
    return getGlyphPainter().getSpan(this, el.getStartOffset(),
                                     el.getEndOffset(), te, x);
  }

  /**
   * Returns the span of a portion of the view. This is used in TAB expansion
   * for fragments that don't contain TABs.
   *
   * @param p0 the start index
   * @param p1 the end index
   *
   * @return the span of the specified portion of the view
   */
  public float getPartialSpan(int p0, int p1)
  {
    Element el = getElement();
    Document doc = el.getDocument();
    Segment seg = new Segment();
    try
      {
        doc.getText(p0, p1 - p0, seg);
      }
    catch (BadLocationException ex)
      {
	AssertionError ae;
        ae = new AssertionError("BadLocationException must not be thrown "
				+ "here");
	ae.initCause(ex);
	throw ae;
      }
    FontMetrics fm = null; // Fetch font metrics somewhere.
    return Utilities.getTabbedTextWidth(seg, fm, 0, null, p0);
  }

  /**
   * Returns the start offset in the document model of the portion
   * of text that this view is responsible for.
   *
   * @return the start offset in the document model of the portion
   *         of text that this view is responsible for
   */
  public int getStartOffset()
  {
    return startOffset;
  }

  /**
   * Returns the end offset in the document model of the portion
   * of text that this view is responsible for.
   *
   * @return the end offset in the document model of the portion
   *         of text that this view is responsible for
   */
  public int getEndOffset()
  {
    return endOffset;
  }

  /**
   * Returns the text segment that this view is responsible for.
   *
   * @param p0 the start index in the document model
   * @param p1 the end index in the document model
   *
   * @return the text segment that this view is responsible for
   */
  public Segment getText(int p0, int p1)
  {
    Segment txt = new Segment();
    try
      {
        getDocument().getText(p0, p1 - p0, txt);
      }
    catch (BadLocationException ex)
      {
	AssertionError ae;
        ae = new AssertionError("BadLocationException should not be "
				+ "thrown here. p0 = " + p0 + ", p1 = " + p1);
	ae.initCause(ex);
	throw ae;
      }

    return txt;
  }

  /**
   * Returns the font for the text run for which this <code>GlyphView</code>