squiggleunderlinehighlightpainter.java

具有不同语法高亮的编辑器实例

/*
 * 09/13/2005
 *
 * SquiggleUnderlineHighlightPainter.java - Highlighter that draws a squiggle
 * underline under "highlighted" text, similar to error markers in Microsoft
 * Visual Studio or Eclipse.
 * Copyright (C) 2005 Robert Futrell
 * [e-mail]
 * www.website.com
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */
package org.fife.ui.rsyntaxtextarea;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Rectangle;
import java.awt.Shape;
import javax.swing.text.BadLocationException;
import javax.swing.text.DefaultHighlighter;
import javax.swing.text.JTextComponent;
import javax.swing.text.Position;
import javax.swing.text.View;


/**
 * Highlight painter that paints a squiggly underline underneath text, similar
 * to what popular IDE's such as Visual Studio and Eclipse do to indicate
 * errors, warnings, etc.<p>
 *
 * This class must be used as a <code>LayerPainter</code>.
 *
 * @author Robert Futrell
 * @version 1.0
 */
public class SquiggleUnderlineHighlightPainter
				extends DefaultHighlighter.DefaultHighlightPainter {

	private static final int AMT			= 2;


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


	/**
	 * Constructor.
	 *
	 * @param color The color of the squiggle.
	 */
	public SquiggleUnderlineHighlightPainter(Color color) {
		super(color);
	}


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


	/**
	 * Paints a portion of a highlight.
	 *
	 * @param g the graphics context
	 * @param offs0 the starting model offset >= 0
	 * @param offs1 the ending model offset >= offs1
	 * @param bounds the bounding box of the view, which is not
	 *        necessarily the region to paint.
	 * @param c the editor
	 * @param view View painting for
	 * @return region drawing occured in
	 */
	public Shape paintLayer(Graphics g, int offs0, int offs1,
						Shape bounds, JTextComponent c, View view) {

		Color color = getColor();
		if (color == null) {
			g.setColor(c.getSelectionColor());
		}
		else {
			g.setColor(color);
		}
		if (offs0 == view.getStartOffset() && offs1 == view.getEndOffset()) {
			// Contained in view, can just use bounds.
			Rectangle alloc;
			if (bounds instanceof Rectangle)
				alloc = (Rectangle)bounds;
			else
				alloc = bounds.getBounds();
			paintSquiggle(g, alloc);
			return alloc;
		}
		else {
			// Should only render part of View.
			try {
				// --- determine locations ---
				Shape shape = view.modelToView(offs0, Position.Bias.Forward,
                                                   offs1,Position.Bias.Backward,
                                                   bounds);
				Rectangle r = (shape instanceof Rectangle) ?
							(Rectangle)shape : shape.getBounds();
				paintSquiggle(g, r);
				return r;
			} catch (BadLocationException e) {
				// can't render
			}
		}

		// Only if exception
		return null;

	}


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


	/**
	 * Paints a squiggle underneath text in the specified rectangle.
	 *
	 * @param g The graphics context with which to paint.
	 * @param r The rectangle containing the text.
	 */
	protected void paintSquiggle(Graphics g, Rectangle r) {
		int x = r.x;
		int y = r.y + r.height-AMT;
		int delta = -AMT;
		while (x<r.x+r.width) {
			g.drawLine(x,y, x+AMT,y+delta);
			y += delta;
			delta = -delta;
			x += AMT;
		}
	}


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

}