Java Graphics Drawing Custom Circular

问题

I want to draw a shape at center that starts from the center of the panel and keeps expanding out in circular shape like in the picture link below :

https://www.dropbox.com/s/lnxi1be8uogn2zx/20140320_124537.jpg

but i am having difficulty with the center shape , its like it doesnt show up at all on the panel. Here is the class i wrote for the shapes

package graphics.test;


import java.awt.Graphics;
import javax.swing.JPanel;

public class DrawPanel extends JPanel {

public void paintComponent(Graphics g){
    super.paintComponent(g);
    int width = getWidth();
    int height = getHeight();

    //top right corner
    g.drawLine(0, 0, width/4, height/6);
    g.drawLine(0, 0, width/4, height/4);
    g.drawLine(0, 0, width/4, height/3);
    //top left corner
    g.drawLine(width, 0, width - width/4, height/6);
    g.drawLine(width, 0, width - width/4, height/4);
    g.drawLine(width, 0, width - width/4, height/3);
    //bottom left corner
    g.drawLine(width, height, width - width/3, height - height/6);
    g.drawLine(width, height, width - width/4, height - height/4);
    g.drawLine(width, height, width - width/4, height - height/3);
    //bottom right corner
    g.drawLine(0, height, width/3, height - height/6);
    g.drawLine(0, height, width/4, height - height/4);
    g.drawLine(0, height, width/4, height - height/3);
    //center

    for (int i = width/2; i < width/3; i--)
    {
        for (int j = height/2; j < height/3; j--)
        {
            g.drawLine(i,j,i,j);
        }
    }


}

}

回答1:

That looks like an Archimedean Spiral ( http://en.wikipedia.org/wiki/Archimedean_spiral )

import java.awt.BasicStroke;
import java.awt.BorderLayout;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Shape;
import java.awt.geom.AffineTransform;
import java.awt.geom.Path2D;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class SpiralDrawPanelTest
{
    public static void main(String[] args)
    {
        SwingUtilities.invokeLater(new Runnable()
        {
            @Override
            public void run()
            {
                createAndShowGUI();
            }
        });
    }

    private static void createAndShowGUI()
    {
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().setLayout(new BorderLayout());
        f.getContentPane().add(new SpiralDrawPanel(),BorderLayout.CENTER);
        f.setSize(800, 800);
        f.setLocationRelativeTo(null);
        f.setVisible(true);
    }
}

class SpiralDrawPanel extends JPanel {

    @Override
    public void paintComponent(Graphics gr)
    {
        super.paintComponent(gr);
        Graphics2D g = (Graphics2D)gr;

        AffineTransform at = 
            AffineTransform.getTranslateInstance(
                getWidth()/2, getHeight()/2);

        BasicStroke stroke =
            new BasicStroke(1.0f,
                BasicStroke.CAP_BUTT,
                BasicStroke.JOIN_MITER,
                10.0f, new float[]{10.0f}, 0.0f);
        g.setStroke(stroke);
        Shape shape = 
            at.createTransformedShape(
                createArchimedeanSpiral(Math.PI*10, 10, 250));
        g.draw(shape);

    }

    private static Shape createArchimedeanSpiral(
        double totalAngleRad, double alpha, int steps)
    {
        Path2D path = new Path2D.Double();
        path.moveTo(0, 0);
        double angleDeltaRad = totalAngleRad / steps;
        for (int i=0; i<=steps; i++)
        {
            double angleRad = i * angleDeltaRad;
            double x = Math.sin(angleRad) * alpha * angleRad;
            double y = Math.cos(angleRad) * alpha * angleRad;
            path.lineTo(x, y);
        }
        return path;

    }
}

---

EDIT for the comment.

import java.awt.BorderLayout;
import java.awt.Graphics;
import java.awt.geom.Path2D;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class SpiralDrawPanelTest
{
    public static void main(String[] args)
    {
        SwingUtilities.invokeLater(new Runnable()
        {
            @Override
            public void run()
            {
                createAndShowGUI();
            }
        });
    }

    private static void createAndShowGUI()
    {
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().setLayout(new BorderLayout());
        f.getContentPane().add(new SpiralDrawPanel(),BorderLayout.CENTER);
        f.setSize(800, 800);
        f.setLocationRelativeTo(null);
        f.setVisible(true);
    }
}

class SpiralDrawPanel extends JPanel {

    @Override
    public void paintComponent(Graphics g)
    {
        super.paintComponent(g);
        paintArchimedeanSpiral(g, getWidth()/2,  getHeight()/2, Math.PI * 10, 10, 250);
    }

    private static void paintArchimedeanSpiral(
        Graphics g, 
        double centerX, double centerY,
        double totalAngleRad, double alpha, int steps)
    {
        Path2D path = new Path2D.Double();
        path.moveTo(0, 0);
        double angleDeltaRad = totalAngleRad / steps;
        for (int i=0; i<=steps; i+=2)
        {
            double angleRad0 = i * angleDeltaRad;
            double angleRad1 = i * angleDeltaRad + angleDeltaRad;
            double x0 = centerX + Math.sin(angleRad0) * alpha * angleRad0;
            double y0 = centerY + Math.cos(angleRad0) * alpha * angleRad0;
            double x1 = centerX + Math.sin(angleRad1) * alpha * angleRad1;
            double y1 = centerY + Math.cos(angleRad1) * alpha * angleRad1;
            g.drawLine((int)x0, (int)y0, (int)x1, (int)y1);
        }
    }
}

来源：https://stackoverflow.com/questions/22530660/java-graphics-drawing-custom-circular