用递归算法绘制分形

Question

我写下面的代码来绘制像照片一样的分形树。但是我在第二种递归方法中有问题。 （用于中间分支长度控制）。如何改进和纠正它？

我的代码：

import java.awt.BasicStroke;
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Component;
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 final 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);
    Component add = 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, 2, true);
}

public void drawFractalTree(Graphics g, int x1, int y1, double angle, int depth, boolean value) {
    if (depth == 0) {
    } else {
        int x2, y2;
        if (value) {
            x2 = x1 + (int) (Math.cos(Math.toRadians(angle)) * depth * 100.0);
            y2 = y1 + (int) (Math.sin(Math.toRadians(angle)) * depth * 100.0);
        } else {
            x2 = (int) ((x1 + (int) (Math.cos(Math.toRadians(angle)) * depth * 100.0)) * 0.3);
            y2 = (int) (y1 + (int) (Math.sin(Math.toRadians(angle)) * depth * 100.0) * 0.3);
        }

        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 + 10, depth - 1, true);
        drawFractalTree(g, x2, y2, angle - 35, depth - 1, false);
        drawFractalTree(g, x2, y2, angle - 70, depth - 1, true);
    }
}

}

我的目标照片： my target photo

我更新了代码：

import java.awt.BasicStroke;
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Component;
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 final 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);
    Component add = 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((Graphics2D) g, WINDOW_WIDTH / 2, WINDOW_HEIGHT - 75, -90, 3,100, 1.0);
}

public void drawFractalTree(Graphics2D g, int x1, int y1, double angle, int depth, double size, double factor) {
if (depth > 0) {
    int x2 = x1 + (int) (Math.cos(Math.toRadians(angle)) * depth * size * factor);
    int y2 = y1 + (int) (Math.sin(Math.toRadians(angle)) * depth * size * factor);

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

    drawFractalTree(g, x2, y2, angle + 10, depth - 1, size, 1.0);
    drawFractalTree(g, x2, y2, angle - 35, depth - 1, size, 0.3);
    drawFractalTree(g, x2, y2, angle - 70, depth - 1, size, 1.0);
} }}

我在此照片链接中展示了我的新结果： new

但是第二个分支长度已经磨损了。我如何像我的第一张照片一样纠正它（目标链接）

Answer 1

您的else 案例中的计算是错误的：

• y2 = ... 行中缺少一些括号
• 您将因子0.3 应用于分支的端点，而不是其长度

试试这个：

} else {
    x2 = x1 + (int) (Math.cos(Math.toRadians(angle)) * depth * 100.0 * 0.3);
    y2 = y1 + (int) (Math.sin(Math.toRadians(angle)) * depth * 100.0 * 0.3);
}

不过，我需要对不同的尺寸和角度参数进行更多微调。

此外，您可以通过提供更多参数并将抗锯齿设置移出方法来稍微简化您的方法：

public void drawFractalTree(Graphics2D g, int x1, int y1, double angle, int depth, double size, double factor) {
    if (depth > 0) {
        int x2 = x1 + (int) (Math.cos(Math.toRadians(angle)) * depth * size * factor);
        int y2 = y1 + (int) (Math.sin(Math.toRadians(angle)) * depth * size * factor);

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

        drawFractalTree(g, x2, y2, angle + 10, depth - 1, size, 1.0);
        drawFractalTree(g, x2, y2, angle - 35, depth - 1, size, 0.3);
        drawFractalTree(g, x2, y2, angle - 70, depth - 1, size, 1.0);
    }
}