scala实验 模拟图形绘制

/**
 * 特征类似于接口，可实现多重继承的功能
 */
case class Point(var x:Double,var y:Double) extends Drawable{
  def shift(deltaX:Double,deltaY:Double){x+=deltaX;y+=deltaY}
}
//特征
trait Drawable{
  def draw(){println(this.toString)}
}

//图形抽象类
abstract class Shape(var point: Point){
  var r=4.0
  def moveTo(point2: Point): Unit ={
    point=point2
  }
  // 抽象方法没有方法体
  def zoom(b:Double): Unit
  //圆形构造函数
  def this(cpoint: Point, cr:Double){
    //第一行必须要先调用默认的构造函数
    this(cpoint: Point)
    this.r=cr
  }
  //直线构造函数
  def this(lpoint:Point,lpoint2:Point){
    this(lpoint: Point)

  }
}
//圆形
class Circle(point: Point,R:Double) extends Shape(point: Point) with Drawable{
  r=R
  //重写，对图形放大，半径放大
  override def zoom(b:Double): Unit = {
    r = r * b
  }
  //重写，打印
  override def draw(): Unit ={
    var toString="Circle center:("+point.x+","+point.y+")\t"+"R="+r
    println(toString)
  }
  //重写，移动
  override def moveTo(point2: Point): Unit ={
    point.x=point2.x
    point.y=point2.y
  }
}
//直线
class Line(point: Point, point1: Point)extends Shape(point: Point) with Drawable{
  //重写，对图形放大
  override def zoom(b:Double): Unit = {
    var xmid=(point1.x+point.x)/2   //寻找中点坐标
    var ymid=(point1.y+point.y)/2
    point.x=xmid-(xmid-point.x)*b
    point.y=ymid-(ymid-point.y)*b
    point1.x=xmid+(point1.x-xmid)*b
    point1.y=ymid+(point1.y-ymid)*b
  }
  //重写，打印
  override def draw(): Unit ={
    var toString="Line:("+point.x+","+point.y+")--"+"（"+point1.x+","+point1.y+")"
    println(toString)
  }
  //重写，移动
  override def moveTo(point2: Point): Unit ={
    point1.x=point1.x+point2.x-point.x
    point1.y=point1.y+point2.y-point.y
    point.x=point2.x
    point.y=point2.y
  }
}

object  MyDraw {
  def main(args: Array[String]) {
    val p=new Point(10,30)
    p.draw;

    val line1 = new Line(Point(0,0),Point(20,20))
    line1.draw
    line1.moveTo(Point(5,5)) //移动到一个新的点
    line1.draw
    line1.zoom(2) //放大两倍
    line1.draw

    val cir= new Circle(Point(10,10),5)
    cir.draw
    cir.moveTo(Point(30,20))
    cir.draw
    cir.zoom(0.5)
    cir.draw
  }
}