Question

上周我一直在研究这个项目，但无法弄清楚如何修复它。我觉得我很近但却无法发现我的错误！我的任务要求我使用Java Graphics类沿假想的线绘制圆圈。在中心画一个半径为n的圆。然后绘制两个半径为n / 2的圆，其端点与圆的左右弧相交。

我已经能够在第一个圆圈的右侧和左侧绘制两个圆圈的第二步。但是，我的程序应该以递归方式绘制四个相同大小的圆圈。左圆圈的右侧和左侧都有一个圆圈，右圆圈的右侧和左侧都有一个圆圈。我的代码有点怀疑。

非常感谢任何帮助。

 package fractalcircles;

 import java.awt.*;
 import javax.swing.*;

 public class FractalCircles {

/**
 * @param args the command line arguments
 */
public static void main(String[] args) 
{   //create a MyCanvas object
    MyCanvas canvas1 = new MyCanvas();

    //set up a JFrame to hold the canvas
    JFrame frame = new JFrame();
    frame.setTitle("FractalCircles.java");
    frame.setSize(500,500);
    frame.setLocation(100,100);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    //add the canvas to the frame as a content panel
    frame.getContentPane().add(canvas1);
    frame.setVisible(true);
}//end main
 }//end class

 class MyCanvas extends Canvas
 {
public MyCanvas()
{} //end MyCanvas() constructor

//this method will draw the initial circle and invisible line
public void paint (Graphics graphics)
{
    int x1,x2,y1,y2; //future x and y coordinates
    int radius=125; //radius of first circle
    int xMid=250, yMid=250; //center point (x,y) of circle

    //draw invisible line
    graphics.drawLine(0,250,500,250);

    //draw first circle
    graphics.drawOval(xMid-radius,yMid-radius,radius*2,radius*2);


    //run fractal algorithm to draw 2 circles to the left and right
   drawCircles(graphics, xMid, yMid, radius);

}

void drawCircles (Graphics graphics, int xMid, int yMid, int radius)
{
    //used to position left and right circles
    int x1 = xMid-radius-(radius/2);
    int y1 = yMid-(radius/2);
    int x2 = xMid+radius-(radius/2);
    int y2= yMid-(radius/2);

    if (radius > 5)
    {
         //draw circle to the left
    graphics.drawOval(x1, y1, (radius/2)*2, (radius/2)*2);

    //draw circle to the right
    graphics.drawOval(x2, y2, (radius/2)*2, (radius/2)*2);
    }

    drawCircles (graphics, xMid, yMid, radius/2);  
}

Answer 1

看起来您的drawCircles功能内只有drawCircles次呼叫。这可能不对，因为每次绘制圆圈时都需要调用递归函数两次。我看到你画的是两个圆圈，但实际上它是向后的。

要使其工作，您需要绘制一个圆，并调用递归函数两次。

以下是您需要更改的内容：

使其成为drawCircle绘制一个圆圈，以坐标为中心
在drawCircle中，调用drawCircle两次，一次使用左侧圆圈，一次使用右侧

应该这样做。

Answer 2

使用递归的一些改编版本... 绘制圆圈，然后通过再次调用相同的函数绘制其2个子项。

void drawCircles(Graphics graphics, int xMid, int yMid, int radius) {
    // end recursion
    if(radius < 5)
        return;

    // Draw circle
    graphics.drawOval(xMid - radius, yMid - radius, radius * 2, radius * 2);

    // start recursion
    //left
    drawCircles(graphics, xMid-radius, yMid, radius / 2);
    //right
    drawCircles(graphics, xMid+radius, yMid, radius / 2);
}

Answer 3

你只是从大圆的每一边画一个圆圈。您需要更改代码。我只写了一个简短的修复，但没有测试。祝你好运

void drawCircles (Graphics graphics, int xMid, int yMid, int radius)
{
//used to position left and right circles
int x1 = xMid-radius-(radius/2);
int x2 = xMid+radius-(radius/2);
int x3 = xMid+radius+(radius/2);
int x4 = xMid-radius+(radius/2);
int y = yMid-(radius/2);


if (radius > 5)
{
     //draw 4 circles
   graphics.drawOval(x1, y, (radius/2)*2, (radius/2)*2);
   graphics.drawOval(x2, y, (radius/2)*2, (radius/2)*2);
   graphics.drawOval(x3, y, (radius/2)*2, (radius/2)*2);
   graphics.drawOval(x4, y, (radius/2)*2, (radius/2)*2);
}

//left
drawCircles(graphics, xMid-radius, yMid, radius / 2);
//right
drawCircles(graphics, xMid+radius, yMid, radius / 2);  
}

使用Java绘制由圆圈组成的分形图案

3 个答案: