glyphview.java

gcc的组建

   * is responsible.
   *
   * @return the font for the text run for which this <code>GlyphView</code>
   *         is responsible
   */
  public Font getFont()
  {
    Element el = getElement();
    AttributeSet atts = el.getAttributes();
    String family = StyleConstants.getFontFamily(atts);
    int size = StyleConstants.getFontSize(atts);
    int style = Font.PLAIN;
    if (StyleConstants.isBold(atts))
        style |= Font.BOLD;
    if (StyleConstants.isItalic(atts))
      style |= Font.ITALIC;
    Font font = new Font(family, style, size);
    return font;
  }

  /**
   * Returns the foreground color which should be used to paint the text.
   * This is fetched from the associated element's text attributes using
   * {@link StyleConstants#getForeground}.
   *
   * @return the foreground color which should be used to paint the text
   */
  public Color getForeground()
  {
    Element el = getElement();
    AttributeSet atts = el.getAttributes();
    return StyleConstants.getForeground(atts);
  }

  /**
   * Returns the background color which should be used to paint the text.
   * This is fetched from the associated element's text attributes using
   * {@link StyleConstants#getBackground}.
   *
   * @return the background color which should be used to paint the text
   */
  public Color getBackground()
  {
    Element el = getElement();
    AttributeSet atts = el.getAttributes();
    return StyleConstants.getBackground(atts);
  }

  /**
   * Determines whether the text should be rendered strike-through or not. This
   * is determined using the method
   * {@link StyleConstants#isStrikeThrough(AttributeSet)} on the element of
   * this view.
   *
   * @return whether the text should be rendered strike-through or not
   */
  public boolean isStikeThrough()
  {
    Element el = getElement();
    AttributeSet atts = el.getAttributes();
    return StyleConstants.isStrikeThrough(atts);
  }

  /**
   * Determines whether the text should be rendered as subscript or not. This
   * is determined using the method
   * {@link StyleConstants#isSubscript(AttributeSet)} on the element of
   * this view.
   *
   * @return whether the text should be rendered as subscript or not
   */
  public boolean isSubscript()
  {
    Element el = getElement();
    AttributeSet atts = el.getAttributes();
    return StyleConstants.isSubscript(atts);
  }

  /**
   * Determines whether the text should be rendered as superscript or not. This
   * is determined using the method
   * {@link StyleConstants#isSuperscript(AttributeSet)} on the element of
   * this view.
   *
   * @return whether the text should be rendered as superscript or not
   */
  public boolean isSuperscript()
  {
    Element el = getElement();
    AttributeSet atts = el.getAttributes();
    return StyleConstants.isSuperscript(atts);
  }

  /**
   * Determines whether the text should be rendered as underlined or not. This
   * is determined using the method
   * {@link StyleConstants#isUnderline(AttributeSet)} on the element of
   * this view.
   *
   * @return whether the text should be rendered as underlined or not
   */
  public boolean isUnderline()
  {
    Element el = getElement();
    AttributeSet atts = el.getAttributes();
    return StyleConstants.isUnderline(atts);
  }

  /**
   * Creates and returns a shallow clone of this GlyphView. This is used by
   * the {@link #createFragment} and {@link #breakView} methods.
   *
   * @return a shallow clone of this GlyphView
   */
  protected final Object clone()
  {
    try
      {
        return super.clone();
      }
    catch (CloneNotSupportedException ex)
      {
        AssertionError err = new AssertionError("CloneNotSupportedException "
                                                + "must not be thrown here");
        err.initCause(ex);
        throw err;
      }
  }

  /**
   * Tries to break the view near the specified view span <code>len</code>.
   * The glyph view can only be broken in the X direction. For Y direction it
   * returns itself.
   *
   * @param axis the axis for breaking, may be {@link View#X_AXIS} or
   *        {@link View#Y_AXIS}
   * @param p0 the model location where the fragment should start
   * @param pos the view position along the axis where the fragment starts
   * @param len the desired length of the fragment view
   *
   * @return the fragment view, or <code>this</code> if breaking was not
   *         possible
   */
  public View breakView(int axis, int p0, float pos, float len)
  {
    if (axis == Y_AXIS)
      return this;

    checkPainter();
    GlyphPainter painter = getGlyphPainter();
    int breakLocation = painter.getBoundedPosition(this, p0, pos, len);
    // Try to find a suitable line break.
    BreakIterator lineBreaker = BreakIterator.getLineInstance();
    Segment txt = new Segment();
    try
      {
        getDocument().getText(getStartOffset(), getEndOffset(), txt);
      }
    catch (BadLocationException ex)
      {
        AssertionError err = new AssertionError("BadLocationException must not "
                                                + "be thrown here.");
        err.initCause(ex);
        throw err;
      }
    lineBreaker.setText(txt);
    int goodBreakLocation = lineBreaker.previous();
    if (goodBreakLocation != BreakIterator.DONE)
      breakLocation = goodBreakLocation;

    View brokenView = createFragment(p0, breakLocation);
    return brokenView;
  }

  /**
   * Determines how well the specified view location is suitable for inserting
   * a line break. If <code>axis</code> is <code>View.Y_AXIS</code>, then
   * this method forwards to the superclass, if <code>axis</code> is
   * <code>View.X_AXIS</code> then this method returns
   * {@link View#ExcellentBreakWeight} if there is a suitable break location
   * (usually whitespace) within the specified view span, or
   * {@link View#GoodBreakWeight} if not.
   *
   * @param axis the axis along which the break weight is requested
   * @param pos the starting view location
   * @param len the length of the span at which the view should be broken
   *
   * @return the break weight
   */
  public int getBreakWeight(int axis, float pos, float len)
  {
    int weight;
    if (axis == Y_AXIS)
      weight = super.getBreakWeight(axis, pos, len);
    else
      {
        // Determine the model locations at pos and pos + len.
        int spanX = (int) getPreferredSpan(X_AXIS);
        int spanY = (int) getPreferredSpan(Y_AXIS);
        Rectangle dummyAlloc = new Rectangle(0, 0, spanX, spanY);
        Position.Bias[] biasRet = new Position.Bias[1];
        int offset1 = viewToModel(pos, spanY / 2, dummyAlloc, biasRet);
        int offset2 = viewToModel(pos, spanY / 2, dummyAlloc, biasRet);
        Segment txt = getText(offset1, offset2);
        BreakIterator lineBreaker = BreakIterator.getLineInstance();
        lineBreaker.setText(txt);
        int breakLoc = lineBreaker.previous();
        if (breakLoc == offset1)
          weight = View.BadBreakWeight;
        else if(breakLoc ==  BreakIterator.DONE)
          weight = View.GoodBreakWeight;
        else
          weight = View.ExcellentBreakWeight;
      }
    return weight;
  }

  /**
   * Receives notification that some text attributes have changed within the
   * text fragment that this view is responsible for. This calls
   * {@link View#preferenceChanged(View, boolean, boolean)} on the parent for
   * both width and height.
   *
   * @param e the document event describing the change; not used here
   * @param a the view allocation on screen; not used here
   * @param vf the view factory; not used here
   */
  public void changedUpdate(DocumentEvent e, Shape a, ViewFactory vf)
  {
    getParent().preferenceChanged(this, true, true);
  }

  /**
   * Receives notification that some text has been inserted within the
   * text fragment that this view is responsible for. This calls
   * {@link View#preferenceChanged(View, boolean, boolean)} on the parent for
   * width.
   *
   * @param e the document event describing the change; not used here
   * @param a the view allocation on screen; not used here
   * @param vf the view factory; not used here
   */
  public void insertUpdate(DocumentEvent e, Shape a, ViewFactory vf)
  {
    getParent().preferenceChanged(this, true, false);
  }

  /**
   * Receives notification that some text has been removed within the
   * text fragment that this view is responsible for. This calls
   * {@link View#preferenceChanged(View, boolean, boolean)} on the parent for
   * width.
   *
   * @param e the document event describing the change; not used here
   * @param a the view allocation on screen; not used here
   * @param vf the view factory; not used here
   */
  public void removeUpdate(DocumentEvent e, Shape a, ViewFactory vf)
  {
    getParent().preferenceChanged(this, true, false);
  }

  /**
   * Creates a fragment view of this view that starts at <code>p0</code> and
   * ends at <code>p1</code>.
   *
   * @param p0 the start location for the fragment view
   * @param p1 the end location for the fragment view
   *
   * @return the fragment view
   */
  public View createFragment(int p0, int p1)
  {
    GlyphView fragment = (GlyphView) clone();
    fragment.startOffset = p0;
    fragment.endOffset = p1;
    return fragment;
  }

  /**
   * Returns the alignment of this view along the specified axis. For the Y
   * axis this is <code>(height - descent) / height</code> for the used font,
   * so that it is aligned along the baseline.
   * For the X axis the superclass is called.
   */
  public float getAlignment(int axis)
  {
    float align;
    if (axis == Y_AXIS)
      {
        checkPainter();
        GlyphPainter painter = getGlyphPainter();
        float height = painter.getHeight(this);
        float descent = painter.getDescent(this);
        align = (height - descent) / height; 
      }
    else
      align = super.getAlignment(axis);

    return align;
  }

  /**
   * Returns the model location that should be used to place a caret when
   * moving the caret through the document.
   *
   * @param pos the current model location
   * @param bias the bias for <code>p</code>
   * @param a the allocated region for the glyph view
   * @param direction the direction from the current position; Must be one of
   *        {@link SwingConstants#EAST}, {@link SwingConstants#WEST},
   *        {@link SwingConstants#NORTH} or {@link SwingConstants#SOUTH}
   * @param biasRet filled with the bias of the resulting location when method
   *        returns
   *
   * @return the location within the document that should be used to place the
   *         caret when moving the caret around the document
   *
   * @throws BadLocationException if <code>pos</code> is an invalid model
   *         location
   * @throws IllegalArgumentException if <code>d</code> is invalid
   */
  public int getNextVisualPositionFrom(int pos, Position.Bias bias, Shape a,
                                       int direction, Position.Bias[] biasRet)
    throws BadLocationException
  {
    checkPainter();
    GlyphPainter painter = getGlyphPainter();
    return painter.getNextVisualPositionFrom(this, pos, bias, a, direction,
                                             biasRet);
  }

  /**
   * Returns the document position that is (visually) nearest to the given
   * document position <code>pos</code> in the given direction <code>d</code>.
   *
   * @param c the text component
   * @param pos the document position
   * @param b the bias for <code>pos</code>
   * @param d the direction, must be either {@link SwingConstants#NORTH},
   *        {@link SwingConstants#SOUTH}, {@link SwingConstants#WEST} or
   *        {@link SwingConstants#EAST}
   * @param biasRet an array of {@link Position.Bias} that can hold at least
   *        one element, which is filled with the bias of the return position
   *        on method exit
   *
   * @return the document position that is (visually) nearest to the given
   *         document position <code>pos</code> in the given direction
   *         <code>d</code>
   *
   * @throws BadLocationException if <code>pos</code> is not a valid offset in
   *         the document model
   */
  public int getNextVisualPositionFrom(JTextComponent c, int pos,
                                       Position.Bias b, int d,
                                       Position.Bias[] biasRet)
    throws BadLocationException
  {
    // TODO: Implement this properly.
    throw new AssertionError("Not implemented yet.");
  }
}