DropShadowBorder.java

/*
 * DropShadowBorder.java
 * :tabSize=4:indentSize=4:noTabs=false:
 * :folding=explicit:collapseFolds=1:
 *
 * Copyright (C) 2016 Dale Anson
 *
 * 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.gjt.sp.jedit.gui;


import java.awt.*;

import javax.swing.border.*;


/**
 * A drop shadow border. Draws a 1 pixel line completely around the component,
 * and a drop shadow effect on the right and bottom sides.  Use this like any
 * other border in javax.swing.borders.
 *
 * @author Dale Anson, 25 Feb 2004
 * @version $Revision: 1.3 $
 */
public class DropShadowBorder extends AbstractBorder
{

    // the width in pixels of the drop shadow
    private int _width = 3;
    // the color of the drop shadow
    private Color _color = Color.BLACK;


    /**
     * Drop shadow with default width of 3 pixels and black color.
     */
    public DropShadowBorder()
    {
        this( 3 );
    }


    /**
     * Drop shadow, default shadow color is black.
     * @param width the width of the shadow.
     */
    public DropShadowBorder( int width )
    {
        this( width, Color.BLACK );
    }


    /**
     * Drop shadow, width and color are adjustable.
     * @param width the width of the shadow.
     * @param color the color of the shadow.
     */
    public DropShadowBorder( int width, Color color )
    {
        _width = width;
        _color = color;
    }


    /**
     * This implementation returns a new Insets instance where the top and left are 1,
     * the bottom and right fields are the border width + 1.
     * @param c the component for which this border insets value applies
     * @return a new Insets object initialized as stated above.
     */
    public Insets getBorderInsets( Component c )
    {
        return new Insets( 1, 1, _width + 1, _width + 1 );
    }


    /**
     * Reinitializes the <code>insets</code> parameter with this DropShadowBorder's
     * current Insets.
     * @param c the component for which this border insets value applies
     * @param insets the object to be reinitialized
     * @return the given <code>insets</code> object
     */
    public Insets getBorderInsets( Component c, Insets insets )
    {
        insets.top = 1;
        insets.left = 1;
        insets.bottom = _width + 1;
        insets.right = _width + 1;
        return insets;
    }


    /**
     * This implementation always returns true.
     * @return true
     */
    public boolean isBorderOpaque()
    {
        return true;
    }


    /**
     * Paints the drop shadow border around the given component.
     * @param c - the component for which this border is being painted
     * @param g - the paint graphics
     * @param x - the x position of the painted border
     * @param y - the y position of the painted border
     * @param width - the width of the painted border
     * @param height - the height of the painted border
     */
    public void paintBorder( Component c, Graphics g, int x, int y, int width, int height )
    {
        Color old_color = g.getColor();
        int x1, y1, x2, y2;
        g.setColor( _color );

        // outline the component with a 1-pixel wide line
        g.drawRect( x, y, width - _width - 1, height - _width - 1 );

        // draw the drop shadow
        for ( int i = 0; i <= _width; i++ )
        {

            // bottom shadow
            x1 = x + _width;
            y1 = y + height - i;
            x2 = x + width;
            y2 = y1;
            g.drawLine( x1, y1, x2, y2 );

            // right shadow
            x1 = x + width - _width + i;
            y1 = y + _width;
            x2 = x1;
            y2 = y + height;
            g.drawLine( x1, y1, x2, y2 );
        }

        // fill in the corner rectangles with the background color of the parent
        // container
        if ( c.getParent() != null )
        {
            g.setColor( c.getParent().getBackground() );
            for ( int i = 0; i <= _width; i++ )
            {
                x1 = x;
                y1 = y + height - i;
                x2 = x + _width;
                y2 = y1;
                g.drawLine( x1, y1, x2, y2 );
                x1 = x + width - _width;
                y1 = y + i;
                x2 = x + width;
                y2 = y1;
                g.drawLine( x1, y1, x2, y2 );
            }

            // add some slightly darker colored triangles
            g.setColor( g.getColor().darker() );
            for ( int i = 0; i < _width; i++ )
            {

                // bottom left triangle
                x1 = x + i + 1;
                y1 = y + height - _width + i;
                x2 = x + _width;
                y2 = y1;
                g.drawLine( x1, y1, x2, y2 );

                // top right triangle
                x1 = x + width - _width;
                y1 = y + i + 1;
                x2 = x1 + i;
                y2 = y1;
                g.drawLine( x1, y1, x2, y2 );
            }
        }


        g.setColor( old_color );
    }
}