ShapeComponent.java

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Insets;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.Shape;
import javax.swing.JComponent;

/**
 *  A component that will paint a Shape object. Click detection will be
 *  determined by the Shape itself, not the bounding Rectangle of the Shape.
 *
 *  Shape objects can be created with an X/Y offset. These offsets will
 *  be ignored and the Shape will always be painted at (0, 0) so the Shape is
 *  fully contained within the component.
 *
 *  The foreground color will be used to "fill" the Shape.
 */
public class ShapeComponent extends JComponent
{
	private Shape shape;
	private boolean antiAliasing = true;

	/**
	 *  Create a ShapeComponent that is painted black.
	 *
	 *  @param shape the Shape to be painted
	 */
	public ShapeComponent(Shape shape)
	{
		this(shape, Color.BLACK);
	}

	/**
	 *  Create a ShapeComponent that is painted filled and outlined.
	 *
	 *  @param shape the Shape to be painted
	 *  @param color the color of the Shape
	 */
	public ShapeComponent(Shape shape, Color color)
	{
		setShape( shape );
		setForeground( color );

		setOpaque( false );
	}

	/**
	 *  Get the Shape of the component
	 *
	 *  @returns the the Shape of the compnent
	 */
	public Shape getShape()
	{
		return shape;
	}

	/**
	 *  Set the Shape for this component
	 *
	 *  @param shape the Shape of the component
	 */
	public void setShape(Shape shape)
	{
		this.shape = shape;
		revalidate();
		repaint();
	}

	/**
	 *  Use AntiAliasing when painting the shape
	 *
	 *  @returns true for AntiAliasing false otherwise
	 */
	public boolean isAntiAliasing()
	{
		return antiAliasing;
	}

	/**
	 *  Set AntiAliasing property for painting the Shape
	 *
	 *  @param antiAliasing true for AntiAliasing, false otherwise
	 */
	public void setAntiAliasing(boolean antiAliasing)
	{
		this.antiAliasing = antiAliasing;
		revalidate();
		repaint();
	}

    /**
     * {@inheritDoc}
     */
	@Override
	public Dimension getPreferredSize()
	{
		//  Include Border insets and Shape bounds

		Insets insets = getInsets();
		Rectangle bounds = shape.getBounds();

		//  Determine the preferred size

		int width = insets.left + insets.right + bounds.width;
		int height = insets.top + insets.bottom + bounds.height;

		return new Dimension(width, height);
	}

    /**
     * {@inheritDoc}
     */
	@Override
	public Dimension getMinimumSize()
	{
		return getPreferredSize();
	}

    /**
     * {@inheritDoc}
     */
	@Override
	public Dimension getMaximumSize()
	{
		return getPreferredSize();
	}

	@Override
	protected void paintComponent(Graphics g)
	{
		super.paintComponent(g);

		//  Graphics2D is required for antialiasing and painting Shapes

		Graphics2D g2d = (Graphics2D)g.create();

		if (isAntiAliasing())
	        g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);

		//  Shape translation (ie. non-zero X/Y position in bounding rectangle)
		//  and Border insets.

		Rectangle bounds = shape.getBounds();
		Insets insets = getInsets();

		//  Do all translations at once

		g2d.translate(insets.left - bounds.x, insets.top - bounds.y);

		//  Fill the Shape

		g2d.fill( shape );

		g2d.dispose();
	}

    /**
     *  Determine if the point is in the bounds of the Shape
     *
     * {@inheritDoc}
     */
	@Override
	public boolean contains(int x, int y)
	{
		Rectangle bounds = shape.getBounds();
		Insets insets = getInsets();

		//  Check to see if the Shape contains the point. Take into account
		//  the Shape X/Y coordinates, Border insets and Shape translation.

		int translateX = x + bounds.x - insets.left;
		int translateY = y + bounds.y - insets.top;

		return shape.contains(translateX, translateY);
	}
}