CS106A assignment2 --problem2 IllusoryContours

/* TODO: A program that show the illusory contour
 * does.
 */
import acm.program.*;
import acm.graphics.*;
import java.awt.*;

public class IllusoryContours extends GraphicsProgram {
    /* The default width and height of the window. These constants will tell Java to
     * create a window whose size is *approximately* given by these dimensions. You should
     * not directly use these constants in your program; instead, use getWidth() and
     * getHeight(), which return the *exact* width and height of the window.
     */
    public static final int APPLICATION_WIDTH = 300;
    public static final int APPLICATION_HEIGHT = 300;
    public static final int CIRCLE_DIAMETER = 100;
    public static double x1=0,y1=0,x2=0,y2=0,x3=0,y3=0,x4=0,y4=0;
    public void run() {
        getCenter();
        showCircle();
        showRect();
    }

    /*
     * 得到四个圆心
     * x代表圆的外切长方形的左上角的x坐标，而非圆心的x坐标
     * y代表的远的外切长方形的左上角的y坐标，而非圆心的y坐标
     */
    private void getCenter() {
        x1 = getWidth() - CIRCLE_DIAMETER;
        y1 = getHeight() - CIRCLE_DIAMETER;
        x2 = 0;
        y2 = 0;
        x3 = getWidth() - CIRCLE_DIAMETER;
        y3 = 0;
        x4 = 0;
        y4 = getHeight() - CIRCLE_DIAMETER;
        
    }
    
    private void showCircle(){
        GOval circle1 = new GOval(x1,y1,CIRCLE_DIAMETER,CIRCLE_DIAMETER);
        GOval circle2 = new GOval(x2,y2,CIRCLE_DIAMETER,CIRCLE_DIAMETER);
        GOval circle3 = new GOval(x3,y3,CIRCLE_DIAMETER,CIRCLE_DIAMETER);
        GOval circle4 = new GOval(x4,y4,CIRCLE_DIAMETER,CIRCLE_DIAMETER);
        circle1.setFilled(true);
        circle1.setFillColor(Color.black);
        add(circle1);
        circle2.setFilled(true);
        circle2.setFillColor(Color.black);
        add(circle2);
        circle3.setFilled(true);
        circle3.setFillColor(Color.black);
        add(circle3);
        circle4.setFilled(true);
        circle4.setFillColor(Color.black);      
        add(circle4);
    }

    private void showRect() {
        double x5 = CIRCLE_DIAMETER/2;
        double y5 = CIRCLE_DIAMETER/2;
        double rectWidth = getWidth() - CIRCLE_DIAMETER;
        double rectHeight = getHeight() - CIRCLE_DIAMETER;
        GRect rect = new GRect(x5,y5,rectWidth,rectHeight);
        rect.setFilled(true);
        rect.setFillColor(Color.white);
        rect.setColor(Color.white);
        add(rect);
    }
}