Question

我有一个Java程序，它将基于递归方法绘制分形树，我想让它看起来平滑增长，我不知道如何做到这一点。

以下是我的代码。这是一个学校作业，只是为了让它成为现实，但基本的任务只是绘制一个分形树，我已经完成了，动画是次要的，更多的是我希望完成的个人目标。

package Question4;

import java.awt.BasicStroke;
import java.awt.Canvas; 
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import javax.swing.JFrame;

public class FractalTree1 extends Canvas {

  // fields for drawing
  private JFrame frame;
  private final int WINDOW_WIDTH = 1280;
  private final int WINDOW_HEIGHT = 720;

  public FractalTree1() {
    frame = new JFrame("Fractal Tree");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(WINDOW_WIDTH, WINDOW_HEIGHT);
    frame.setLocationRelativeTo(null);
    frame.setResizable(true);
    frame.add(this);
    frame.setVisible(true);
  }

  public static void main(String[] args) {
    FractalTree1 ft = new FractalTree1();
    ft.setVisible(true);
    ft.setBackground(Color.black);
  }

  @Override
  public void paint(Graphics g) {
    g.setColor(Color.green);
    drawFractalTree(g, WINDOW_WIDTH / 2, WINDOW_HEIGHT - 75, -90, 11);
  }

  public void drawFractalTree(Graphics g, int x1, int y1, double angle, int depth) {
    if (depth == 0) {
    } else {
      int x2 = x1 + (int) (Math.cos(Math.toRadians(angle)) * depth * 10.0);
      int y2 = y1 + (int) (Math.sin(Math.toRadians(angle)) * depth * 10.0);

      Graphics2D g2d = (Graphics2D) g;
      g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,     RenderingHints.VALUE_ANTIALIAS_ON);

      g2d.setStroke(new BasicStroke(0.5f * depth));
      g2d.drawLine(x1, y1, x2, y2);

      drawFractalTree(g, x2, y2, angle + 30, depth - 1);
      drawFractalTree(g, x2, y2, angle - 30, depth - 1);
    }
  } 
}

EDIT 现在作为一个跟进...当我向它添加Thread.sleep（）时，它会尴尬地看起来就像递归绘制它一样。是否可以强制它从＆＃34; trunk＆＃34;因此，它模拟了一棵真正的树＆＃34;成长＆＃34;？

Answer 1

要实现这一点，您可能需要使用double buffering。基本上，你绘制一个离屏缓冲区，并在绘图完成后将其刷新到屏幕上。

在drawFractalTree（）方法中，您必须添加Thread.sleep（）调用以延迟绘图。在g2d.drawLine（x1，y1，x2，y2）之后直接添加;应该做的伎俩。它最终可能会非常缓慢。为了抑制这种情况，您可以使用计数器并在每10次通话后休眠1ms。

Answer 2

要开始看一些动画，请在drawFractalTree（）的开头添加一个Thread.sleep（100）调用。

Answer 3

Thread.sleep(100);

如果您使用图像从图形中进行绘制而不是直接绘制，则效果非常好。因此，每次绘制图像像素的颜色都不会改变。

package Question4;

import java.awt.BasicStroke;
import java.awt.Canvas; 
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import javax.swing.JFrame;

public class FractalTree1 extends Canvas {

// fields for drawing
private JFrame frame;
private final int WINDOW_WIDTH = 1280;
private final int WINDOW_HEIGHT = 720;

private Image buffer = createImage(WINDOW_WIDTH,WINDOW_HEIGHT);
private Graphics bufferg = buffer.getGraphics();
public FractalTree1() {
    frame = new JFrame("Fractal Tree");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(WINDOW_WIDTH, WINDOW_HEIGHT);
    frame.setLocationRelativeTo(null);
    frame.setResizable(true);
    frame.add(this);
    frame.setVisible(true);
}

public static void main(String[] args) {
   FractalTree1 ft = new FractalTree1();
   ft.setVisible(true);
   ft.setBackground(Color.black);
   bufferg.setColor(Color.green);
}

@Override
public void paint(Graphics g) {
    g.drawImage(buffer,0,0,null);
    drawFractalTree(g, WINDOW_WIDTH / 2, WINDOW_HEIGHT - 75, -90, 11);
}

public void drawFractalTree(Graphics g, int x1, int y1, double angle, int depth) {

    if (depth == 0) {
    } else {
    Thread.sleep(100);//It has a catch exception here;
    int x2 = x1 + (int) (Math.cos(Math.toRadians(angle)) * depth * 10.0);
    int y2 = y1 + (int) (Math.sin(Math.toRadians(angle)) * depth * 10.0);

    Graphics2D g2d = (Graphics2D) bufferg;
    g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,           RenderingHints.VALUE_ANTIALIAS_ON);

    g2d.setStroke(new BasicStroke(0.5f * depth));
    g2d.drawLine(x1, y1, x2, y2);
    repaint();
    drawFractalTree(g, x2, y2, angle + 30, depth - 1);
    drawFractalTree(g, x2, y2, angle - 30, depth - 1);
    }
   } 
}

平滑地动画分形树

3 个答案: