如何平滑圓角矩形中的拐角，Swing？

Question

當我嘗試製作圓角矩形時，出現非常像素化的邊角。有什麼方法可以使它們變得平滑？

下面是一個圖像（注意拐角）：

這裏是我子類並覆蓋paint方法（帶有像素化角落）按鈕的代碼：

public class ControlButton extends JButton { 

    public final static Color BUTTON_TOP_GRADIENT = new Color(176, 176, 176); 
    public final static Color BUTTON_BOTTOM_GRADIENT = new Color(156, 156, 156); 

    public ControlButton(String text) { 
     setText(text); 
    } 

    public ControlButton() { 
    } 

    @Override 
    protected void paintComponent(Graphics g){ 
     Graphics2D g2 = (Graphics2D)g.create(); 
     g2.setPaint(new GradientPaint(
       new Point(0, 0), 
       BUTTON_TOP_GRADIENT, 
       new Point(0, getHeight()), 
       BUTTON_BOTTOM_GRADIENT)); 
     g2.fillRoundRect(0, 0, getWidth(), getHeight(), 20, 20); 
     g2.dispose(); 
    } 
} 

Answer 1

試試這個：

RenderingHints qualityHints = new RenderingHints(
    RenderingHints.KEY_ANTIALIASING, 
    RenderingHints.VALUE_ANTIALIAS_ON); 
qualityHints.put(
    RenderingHints.KEY_RENDERING, 
    RenderingHints.VALUE_RENDER_QUALITY); 
g2.setRenderingHints(qualityHints); 

看看日出入口文件：

• http://docs.oracle.com/javase/tutorial/2d/advanced/quality.html

代碼：

import javax.swing.*; 

import java.awt.*; 

public class ControlButton extends JButton { 

    public final static Color BUTTON_TOP_GRADIENT = new Color(176, 176, 176); 
    public final static Color BUTTON_BOTTOM_GRADIENT = new Color(156, 156, 156); 

    public ControlButton(String text) { 
    setText(text); 
    } 

    public ControlButton() { 
    } 

    @Override 
    protected void paintComponent(Graphics g) { 
    Graphics2D g2 = (Graphics2D)g.create(); 
    RenderingHints qualityHints = 
     new RenderingHints(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); 
    qualityHints.put(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY); 
    g2.setRenderingHints(qualityHints); 

    g2.setPaint(new GradientPaint(new Point(0, 0), BUTTON_TOP_GRADIENT, new Point(0, getHeight()), 
            BUTTON_BOTTOM_GRADIENT)); 
    g2.fillRoundRect(0, 0, getWidth(), getHeight(), 20, 20); 
    g2.dispose(); 
    } 

    public static void main(String args[]) { 
    JFrame frame = new JFrame("test"); 
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
    frame.getContentPane().add(new ControlButton("Hello, World")); 
    frame.pack(); 
    frame.setVisible(true); 
    } 
}