（1）先定义要实现的类，我先定义了一个抽象类
代码如下:
//图形类
abstract class Shape{
int x,y;
int x1,y1;
Color color ;
Graphics g ;
byte type ;
public abstract void draw(Graphics g) ;
}
//直线类
class LineShape extends Shape{
public LineShape(int x, int y ,int x1,int y1,Color color){
this.x = x ;
this.y = y ;
this.x1 = x1 ;
this.y1 = y1 ;
this.color = color ;
this.type = 0;
}
@Override
public void draw(Graphics g) {
g.setColor(color) ;
g.drawLine(x, y, x1, y1) ;
}
}
//圆类
class OvalShape extends Shape{
public OvalShape(int x,int y, int x1,int y1,Color color){
this.x = x ;
this.y = y ;
this.x1 = x1 ;
this.y1 = y1 ;
this.color = color ;
this.type = 1;
}
@Override
public void draw(Graphics g) {
g.setColor(color) ;
g.drawOval((x+x1)/2,(y+y1)/2,(x1-x)/2 ,(y1-y)/2 );
}
}
//图片类
class picture extends Shape{
int a ;
int b ;
int cl[][] ;
public picture(int a,int b,int cl[][]){
this.type =2 ;
this.a =a ;
this.b =b ;
this.cl =cl ;
}
public void draw(Graphics g){
for(int k=0;k