圖形拱不準確

Question

我必須在java中繪製精確的拱形。我使用Graphics2D.fillArc（）的currenlty。問題是它只接受整數，而且曲線不準確，我不能使弧度順利增加。有沒有人知道這個解決方法？

Answer 1

這是我的SSCCE使用Arc2D。

import java.awt.*; 
import java.awt.event.*; 
import java.awt.geom.Arc2D; 
import javax.swing.*; 

@SuppressWarnings("serial") 
public class ChangingArcs extends JPanel { 
    private static final Color ARC_FILL_COLOR = Color.RED; 
    private static final int TIMER_DELAY = 20; 
    private static final int ARC_X = 100; 
    private static final int ARC_Y = 100; 
    private static final int ARC_W = 500; 
    private static final int ARC_H = 500; 
    protected static final double DELTA_EXTEND = 0.5; 
    private Arc2D arc; 
    private double extend = 0; 

    public ChangingArcs() { 
     new Timer(TIMER_DELAY, new ActionListener() { 
     public void actionPerformed(ActionEvent e) { 
      extend += DELTA_EXTEND; 
      extend %= 360; 
      double start = -extend/2; 
      arc = new Arc2D.Double(ARC_X, ARC_Y, ARC_W, ARC_H, start, extend, Arc2D.PIE); 
      repaint(); 
     } 
     }).start(); 
    } 

    public Dimension getPreferredSize() { 
     return new Dimension(ARC_W + 2 * ARC_X, ARC_H + 2 * ARC_Y); 
    } 

    @Override 
    protected void paintComponent(Graphics g) { 
     super.paintComponent(g); 
     Graphics2D g2 = (Graphics2D)g; 
     if (arc != null) { 
     g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); 
     g2.setColor(ARC_FILL_COLOR); 
     g2.fill(arc); 
     } 
    } 

    private static void createAndShowUI() { 
     JFrame frame = new JFrame("ChangingArcs"); 
     frame.getContentPane().add(new ChangingArcs()); 
     frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
     frame.pack(); 
     frame.setLocationRelativeTo(null); 
     frame.setVisible(true); 
    } 

    public static void main(String[] args) { 
     java.awt.EventQueue.invokeLater(new Runnable() { 
     public void run() { 
      createAndShowUI(); 
     } 
     }); 
    } 
}