rectangularcake.java

Java程序设计(美) David D. Riley著 机械工业出版社 书籍配套 代码

// Figure 9.9

import java.awt.*;
public class RectangularCake extends Cake  {
    private	Rectangle theCake;
	
	/**	post:	getX() == x  and  getY() == y
	 *          and  getWidth() == w  and  getHeight() == h
	 *          and  getBackground == Color.yellow 
	 */
    public RectangularCake( int x, int y, int w, int h )  {
    	super(x, y, w, h);
		setBackground( Color.yellow );
	}

	/**	post:	the cake is drawn as a rectangle filling the bounding rectangle
	 *	   		and the color of the cake is getBackground() 
	 */
	protected void paintCake( Graphics g )   {
		g.setColor( getBackground() );
		g.fillRect(0, 0, getWidth(), getHeight());
	}

	/**	post:	two black lines (one vertical and one horizontal) divide 
	 *						the cake into fourths
	 *	   		and getWidth() > getHeight() implies the cake is separated by 
	 *						two more vertical lines making 8 equal-sized pieces.
	 *	   		and getWidth() <= getHeight() implies the cake is separated by 
	 *						two more horizontal lines making 8 equal-sized pieces. 
	 */
	protected void paintEighthCuts( Graphics g )   {
		g.setColor( Color.black );
		g.drawLine(0, getHeight()/2, getWidth(), getHeight()/2);
		g.drawLine(getWidth()/2, 0, getWidth()/2, getHeight());
		if ( getWidth() > getHeight() )   {
			g.drawLine(getWidth()/4, 0, getWidth()/4, getHeight());
			g.drawLine(getWidth()*3/4, 0, getWidth()*3/4, getHeight());
		} else {
			g.drawLine(0, getHeight()/4, getWidth(), getHeight()/4);
			g.drawLine(0, getHeight()*3/4, getWidth(), getHeight()*3/4);
		}
	}
}