Shadow Border
28/01/2009
/*
* Created on 17 oct. 06
* By Gabriel DROMARD
*/
import java.awt.AlphaComposite;
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Insets;
import java.awt.RenderingHints;
import javax.swing.JPanel;
import javax.swing.border.AbstractBorder;
/**
* A class which implements a shadow border.
*
* <p>Code Example: </p>
* <pre>
* JPanel root = new JPanel();
* // Generate 4 example for each TOP_LEFT, TOP_RIGHT, BOTTOM_LEFT and BOTTOM_RIGHT configurations
* for(int i=0; i<4; ++i) {
* JPanel test = new JPanel();
* test.setPreferredSize(new Dimension(100, 100));
* test.setBackground(Color.WHITE);
* test.setOpaque(false);
* test.setBorder(new ShadowBorder(Color.GRAY, Color.GRAY, 10, i));
* root.add(test);
* }
* //SwingHelper.openInFrame(root);
* JFrame frame = new JFrame();
* frame.getContentPane().setLayout(new BorderLayout());
* frame.getContentPane().add(root, BorderLayout.CENTER);
* frame.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
* frame.pack();
* frame.setVisible(true);
* </pre>
*/
public class ShadowBorder extends AbstractBorder {
private int shadowWidth = 10;
private int inset = 5;
protected Color lineBorderColor = null;
protected Color shadowColor = null;
protected int type = 2;
public static final int TOP_LEFT = 0;
public static final int TOP_RIGHT = 1;
public static final int BOTTOM_LEFT = 2;
public static final int BOTTOM_RIGHT = 3;
/**
* Auto-generated main method to display this
* JPanel inside a new JFrame.
*/
public static void main(String[] args) {
JPanel root = new JPanel();
for(int i=0; i<4; ++i) {
JPanel test = new JPanel();
test.setPreferredSize(new Dimension(100, 100));
test.setBackground(Color.WHITE);
test.setOpaque(false);
test.setBorder(new ShadowBorder(Color.GRAY, Color.GRAY, 10, i));
root.add(test);
}
SwingHelper.openInFrame(root);
}
/**
* Creates a shadow border with the specified shadow width and whose
* colors will be derived from the background color of the
* component passed into the paintBorder method.
* @param shadowWidth the length of shadow
* @param
* @param
* @param
*/
public ShadowBorder(Color shadowColor, Color lineBorderColor, int shadowWidth, int type) {
super();
this.shadowWidth = shadowWidth;
this.shadowColor = shadowColor;
this.lineBorderColor = lineBorderColor;
this.type = type;
}
/**
* Returns the insets of the border.
* @param c the component for which this border insets value applies
*/
public Insets getBorderInsets(Component c) {
int hPosition = shadowWidth;
int vPosition = shadowWidth;
if(type == TOP_LEFT) {
hPosition = 0;
vPosition = 0;
} else if(type == TOP_RIGHT) {
hPosition = shadowWidth;
vPosition = 0;
} else if(type == BOTTOM_LEFT) {
hPosition = 0;
vPosition = shadowWidth;
} else if(type == BOTTOM_RIGHT) {
hPosition = shadowWidth;
vPosition = shadowWidth;
}
return new Insets((shadowWidth - hPosition)+inset, (shadowWidth - vPosition)+inset, hPosition+inset, vPosition+inset);
}
/**
* Reinitialize the insets parameter with this Border's current Insets.
* @param c the component for which this border insets value applies
* @param insets the object to be reinitialized
*/
public Insets getBorderInsets(Component c, Insets insets) {
insets.left = insets.top = insets.right = insets.bottom = shadowWidth+2;
return insets;
}
/**
* Returns the shadow color of the border
* when rendered on the specified component. If no shadow
* color was specified at instantiation, the shadow color
* is derived from the specified component's background color.
* @param c the component for which the shadow may be derived
*/
public Color getShadowColor(Component c) {
Color shadow = getShadowColor();
if(shadow == null) shadow = c.getBackground().darker().darker();
return shadow;
}
/**
* Returns the shadow color of the border.
* Will return null if no shadow color was specified at instantiation.
*/
public Color getShadowColor() {
return shadowColor;
}
/**
* Returns whether or not the border is opaque.
*/
public boolean isBorderOpaque() {
return true;
}
/**
* Paints the border for the specified component with the specified position and size.
* @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) {
int hPosition = shadowWidth;
int vPosition = shadowWidth;
if(type == TOP_LEFT) {
hPosition = 0;
vPosition = 0;
} else if(type == TOP_RIGHT) {
hPosition = shadowWidth;
vPosition = 0;
} else if(type == BOTTOM_LEFT) {
hPosition = 0;
vPosition = shadowWidth;
} else if(type == BOTTOM_RIGHT) {
hPosition = shadowWidth;
vPosition = shadowWidth;
}
width = width - 1;
height = height - 1;
Graphics2D gg = (Graphics2D) g;
// backup old color to be able to restore it at the end of paint
Color oldColor = gg.getColor();
// Translate position
gg.translate(x, y);
// paint shadow
paintShadow(c, gg, getShadowColor(c), hPosition, vPosition, width-shadowWidth, height-shadowWidth, shadowWidth);
// Fill with background color the panel
gg.setColor(c.getBackground());
gg.fillRect(shadowWidth - hPosition, shadowWidth - vPosition, width-shadowWidth, height-shadowWidth);
// Draw line border
if (lineBorderColor != null) {
gg.setColor(lineBorderColor);
gg.drawRect(shadowWidth - hPosition, shadowWidth - vPosition, width-shadowWidth, height-shadowWidth);
}
// Reset position
gg.translate(-x, -y);
// Re put oldColor
gg.setColor(oldColor);
}
/**
*
* @param c the component for which this border is being painted
* @param gg the paint graphics
* @param shadowColor The color of the shadow
* @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
* @param shadowWidth The shadow width
*/
public static void paintShadow(Component c, Graphics2D gg, Color shadowColor, int x, int y, int width, int height, int shadowWidth) {
// Set anti aliasing
gg.setRenderingHint(RenderingHints.KEY_ANTIALIASING , RenderingHints.VALUE_ANTIALIAS_ON);
// Draw shadow
AlphaComposite ac = null;
gg.setColor(shadowColor);
// Initial shadow width:
int sw = width - 2*shadowWidth;
// Initial shadow height:
int sh = height - 2*shadowWidth;
// Draw shadow
for(int i=0; i<shadowWidth; ++i) {
ac = AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 1f/(i+1));
gg.setComposite(ac);
gg.fillRoundRect(x+shadowWidth-i, y+shadowWidth-i, sw + 2*i, sh + 2*i, i*2, i*2);
}
// Reset transparency
ac = AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 1);
gg.setComposite(ac);
}
}
