linenumberlist.java

具有不同语法高亮的编辑器实例

    if (textAreaInsets != null) {
      actualTopY += textAreaInsets.top;
    }
    int y = actualTopY + ascent;

    // Highlight the current line's line number, if desired.
    if (textArea.isCurrentLineHighlightEnabled() && currentLine >= topLine &&
        currentLine < bottomLine) {
      g.setColor(textArea.getCurrentLineHighlightColor());
      g.fillRect(0, actualTopY + (currentLine - topLine) * cellHeight,
                 cellWidth, cellHeight);
    }

    // Paint the "border" line.
    g.setColor(Color.BLACK);
    g.drawLine(cellWidth - 4, 0, cellWidth - 4, visibleRect.height);

    g.setColor(getForeground());
    FontMetrics metrics = g.getFontMetrics();
    int rhs = getBounds().width - RHS_BORDER_WIDTH;
    for (int i = topLine; i < bottomLine; i++) {
      String number = Integer.toString(i);
      int width = getTextWidth(number, metrics);
      g.drawString(number, rhs - width, y);
      y += cellHeight;
    }

  }

      /*****************************************************************************/

  /**
   * Paints line numbers for text areas with line wrap enabled.
   *
   * @param g The graphics context.
   * @param root The root element of the document being painted.
   * @param visibleRect The visible rectangle of the text area.
   */
  /*
   * FIXME:  This method isn't as efficient as the version in
   * LineNumberBorder, as it uses modelToView() a lot.  Fix it to be like
   * LineNumberBorder's version if you ever use this again.
   */
  public void paintWrappedLineNumbers(Graphics g, Element root,
                                      Rectangle visibleRect) {

    // The variables we use are as follows:
    // visibleRect is the "visible" area of the text area; e.g.
    // [0,100, 300,100+(numLines*cellHeight)-1].
    // actualTop.y is the topmost-pixel in the first logical line we paint.
    // Note that we may well not paint this part of the logical line, as it
    // may be broken into many physical lines, with the first few physical
    // lines scrolled past.  Note also that this is NOT the visible rect of
    // this line number list; this line number list has visible rect ==
    // [0,0, cellWidth-1,visibleRect.height-1].
    // offset (<=0) is the y-coordinate at which we begin painting when we
    // begin painting with the first logical line.  This can be negative
    // signifying that we've scrolled past the actual topmost part of this line.
    // The algorithm is as follows:
    // - Get the starting y-coordinate at which to paint.  This may be above the
    //   first visible y-coordinate as we're in line-wrapping mode, but we
    //   always paint entire logical lines.
    // - Paint that line's line number and highlight, if appropriate.  Increment
    //   y to be just below the are we just painted (i.e., the beginning of the
    //   next logical line's view area).
    // - Get the ending visual position for that line.  We can now loop back,
    //   paint this line, and continue until our y-coordinate is past the last
    //   visible y-value.

    int lineCount = root.getElementCount();
    int topPosition = textArea.viewToModel(new Point(visibleRect.x,
        visibleRect.y));
    int topLine = root.getElementIndex(topPosition);
    Element line = root.getElement(topLine);
    int topLineStartOffset = line.getStartOffset();
    int topLineEndOffset = line.getEndOffset();

    // Compute the y at which to begin painting text, taking into account scrolling.
    Rectangle actualTop = null;
    try {
      actualTop = textArea.modelToView(topLineStartOffset); // Could be (0,-5), for example.
    }
    catch (Exception e) {
      e.printStackTrace();
      return;
    }

    int offset = actualTop.y - visibleRect.y; // How much "higher" we are than the actual viewport (negative value).
    int y = offset; // The y-coordinate at which we're painting.

    g.setColor(getForeground());
    FontMetrics metrics = g.getFontMetrics();
    int rhs = getBounds().width - RHS_BORDER_WIDTH;
    int visibleBottom = visibleRect.height;

    // Keep painting lines until our y-coordinate is passed the visible end of
    // the text area.
    while (y < visibleBottom) {

      // Compute the next y-value at which to paint a line number.
      // This is also needed to know how much to highlight when
      // highlighting the current line number.
      Rectangle lineEndViewPos = null;
      try {
        lineEndViewPos = textArea.modelToView(topLineEndOffset - 1);
        lineEndViewPos.y -= visibleRect.y; // Take into account we always start at y==0.
      }
      catch (BadLocationException ble) {
        ble.printStackTrace();
        break;
      }

      // Highlight the current line's line number, if desired.
      if (textArea.isCurrentLineHighlightEnabled() &&
          topLine == currentLine - 1) {
        g.setColor(textArea.getCurrentLineHighlightColor());
        g.fillRect(0, y, cellWidth,
                   lineEndViewPos.y + lineEndViewPos.height - y);
        g.setColor(getForeground());
      }

      // Paint the line number.
      String number = Integer.toString(topLine + 1);
      int width = getTextWidth(number, metrics);
      g.drawString(number, rhs - width, y + ascent);

      // The next possible y-coordinate is just after the last line
      // painted.
      y = lineEndViewPos.y + lineEndViewPos.height;

      // Update topLine (we're actually using it for our "current line" variable now).
      topLine++;
      if (topLine >= lineCount) {
        break;
      }
      topLineEndOffset = root.getElement(topLine).getEndOffset();

    }

    // Paint the "border" line.  Remember that the line number list doesn't
    // scroll and always has visible rect ==
    // [0,0, cellWidth-1,visibleRect.height-1].
    g.setColor(Color.BLACK);
    int x = cellWidth - 4;
    g.drawLine(x, 0, x, visibleRect.height - 1);

  }

      /*****************************************************************************/

  public void propertyChange(PropertyChangeEvent e) {

    String name = e.getPropertyName();

    // If they changed the background color of the text area.
    if (name.equals("background")) {
      Color bg = textArea.getBackground();
      setBackground(bg == null ? Color.WHITE : bg);
      repaint();
    }

    // If they changed the background to an image.
    if (name.equals("background.image")) {
      setBackground(Color.WHITE);
      repaint();
    }

    // They toggled lineWrap in the text area.
    else if (name.equals("lineWrap")) {
      lastY = -1; // Just to force a repaint if lineWrap is being enabled.
      setSize(getWidth(), textArea.getHeight());
    }

    // If they change the text area's font, we need to update cell heights
    // to match the font's height.
    else if (name.equals("font")) {
      updateCellHeights();
    }

    // If they change the current line highlight in any way...
    else if (name.equals(RTextArea.CURRENT_LINE_HIGHLIGHT_PROPERTY) ||
             name.equals(RTextArea.CURRENT_LINE_HIGHLIGHT_COLOR_PROPERTY)) {
      repaint();
    }

  }

      /*****************************************************************************/

  /**
   * Called whenever a character is removed (ie backspace, delete) in the
   * text document we're line-numbering.
   */
  public void removeUpdate(DocumentEvent e) {
    int newNumLines = textArea.getDocument().getDefaultRootElement().
        getElementCount();
    if (newNumLines < currentNumLines) { // Used to be <=
      // Adjust the amount of space the line numbers take up, if necessary.
      if (newNumLines / 10 < currentNumLines / 10) {
        updateCellWidths();
      }
      currentNumLines = newNumLines;
      repaint();
    }
  }

      /*****************************************************************************/

  /**
   * Sets the font used to render the line numbers.
   *
   * @param font The <code>java.awt.Font</code> to use to to render the line
   *             numbers.  If <code>null</code>, a 10-point monospaced font
   *             will be used.
   * @see #getFont
   */
  public void setFont(Font font) {
    if (font == null) {
      font = new Font("monospaced", Font.PLAIN, 10);
    }
    super.setFont(font);
  }

      /*****************************************************************************/

  /**
   * Sets the color to use to paint line numbers.
   *
   * @param color The color to use when painting line numbers.
   * @see #getLineNumberColor
   */
  public void setLineNumberColor(Color color) {
    setForeground(color);
    repaint();
  }

      /*****************************************************************************/

  /**
   * Changes the height of the cells in the JList so that they are as tall as
   * font. This function should be called whenever the user changes the Font
   * of <code>textArea</code>.
   */
  public void updateCellHeights() {
    //FontMetrics fontMetrics = textArea.getFontMetrics(textArea.getFont());
    cellHeight = textArea.getLineHeight(); //fontMetrics.getHeight();
    ascent = textArea.getMaxAscent(); //fontMetrics.getAscent();
    repaint();
  }

      /*****************************************************************************/

  /**
   * Changes the width of the cells in the JList so you can see every digit
   * of each.
   */
  public void updateCellWidths() {

    // Adjust the amount of space the line numbers take up, if necessary.
    Font font = getFont();
    if (font != null) {
      FontMetrics fontMetrics = getFontMetrics(font);
      int count = 0;
      int numLines = textArea.getDocument().getDefaultRootElement().
          getElementCount();
      while (numLines >= 10) {
        numLines = numLines / 10;
        count++;
      }
      cellWidth = Math.max(fontMetrics.charWidth('9') * (count + 2) + 5,
                           MIN_CELL_WIDTH);
      revalidate();
    }

  }

      /*****************************************************************************/

}