linenumberlist.java~2~

具有不同语法高亮的编辑器实例

		// the first line.
		int actualTopY = -(visibleRect.y%cellHeight);
		Insets textAreaInsets = textArea.getInsets();
		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();
		}

	}


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

}