GradientPanel.java

/*-
 *  This class was developed for the soapUI software poduct, distributed under LGPL.
 *
 *  soapUI, copyright (C) 2004-2009 eviware.com
 *
 *  soapUI is free software; you can redistribute it and/or modify it under the
 *  terms of version 2.1 of the GNU Lesser General Public License as published by
 *  the Free Software Foundation.
 *
 *  soapUI 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 Lesser General Public License for more details at gnu.org.
 */
package ro.bmocanu.swing.components;

import java.awt.*;

import javax.swing.JPanel;

public class GradientPanel extends JPanel {
    private static final long serialVersionUID = 1L;

    // ------------------------------ FIELDS ------------------------------

    public final static int HORIZONTAL = 0;
    public final static int VERTICAL = 1;
    public final static int DIAGONAL_LEFT = 2;
    public final static int DIAGONAL_RIGHT = 3;

    private int direction = HORIZONTAL;
    private boolean cyclic;
    private int maxLength;

    // --------------------------- CONSTRUCTORS ---------------------------

    public GradientPanel() {
	this(HORIZONTAL);
    }

    public GradientPanel(int direction) {
	setOpaque(false);
	this.direction = direction;
    }

    // --------------------- GETTER / SETTER METHODS ---------------------

    public int getDirection() {
	return direction;
    }

    public void setDirection(int direction) {
	this.direction = direction;
    }

    public boolean isCyclic() {
	return cyclic;
    }

    public void setCyclic(boolean cyclic) {
	this.cyclic = cyclic;
    }

    public int getMaxLength() {
	return maxLength;
    }

    public void setMaxLength(int maxLength) {
	this.maxLength = maxLength;
    }

    // -------------------------- OTHER METHODS --------------------------

    public void paintComponent(Graphics g) {
	if (isOpaque()) {
	    super.paintComponent(g);
	    return;
	}

	int width = getWidth();
	int height = getHeight();

	// Create the gradient paint
	GradientPaint paint = null;

	Color sc = getForeground();
	Color ec = getBackground();

	switch (direction) {
	    case HORIZONTAL: {
		paint = new GradientPaint(0, height / 2, sc, width, height / 2,
		        ec, cyclic);
		break;
	    }
	    case VERTICAL: {
		paint = new GradientPaint(width / 2, 0, sc, width / 2,
		        maxLength > 0 ? maxLength : height, ec, cyclic);
		break;
	    }
	    case DIAGONAL_LEFT: {
		paint = new GradientPaint(0, 0, sc, width, height, ec, cyclic);
		break;
	    }
	    case DIAGONAL_RIGHT: {
		paint = new GradientPaint(width, 0, sc, 0, height, ec, cyclic);
		break;
	    }
	}

	if (paint == null) {
	    throw new RuntimeException(
		    "Invalid direction specified in GradientPanel");
	}

	// we need to cast to Graphics2D for this operation
	Graphics2D g2d = (Graphics2D) g;

	// save the old paint
	Paint oldPaint = g2d.getPaint();

	// set the paint to use for this operation
	g2d.setPaint(paint);

	// fill the background using the paint
	g2d.fillRect(0, 0, width, height);

	// restore the original paint
	g2d.setPaint(oldPaint);

	super.paintComponent(g);
    }
}