java - 如何平滑我的 JFrame 形状

Question

我给了我的 JFrame 窗口一个带有圆角的自定义形状，但我怎样才能平滑它（抗锯齿）

Answer 1

很大程度上取决于您如何渲染内容，但基本概念是为Graphics您正在绘制的上下文提供渲染提示......

例如，如果我正在绘制一个组件，我可能会使用类似...

// Create a "copy" of the graphics context so we don't modify any of it's existing
// settings.  This makes it easier to manage the graphics context as we 
// may not want to effect anything else that might be using this graphics context
// into the future
Graphics2D g2d = (Graphics2D)g.create();
RenderingHints hints = new RenderingHints(
    RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON
);
g2d.setRenderingHints(hints);
//... continue drawing.
// Dispose of our "copy" of the graphics context
g2d.dispose();

查看控制渲染质量了解更多详情

更新了示例

public class AATest {

    public static void main(String[] args) {
        new AATest();
    }

    public AATest() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                }

                JFrame frame = new JFrame();
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setLayout(new BorderLayout());
                frame.add(new PaintPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class PaintPane extends JPanel {

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(215, 110);
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            Graphics2D g2d = (Graphics2D) g.create();
            RenderingHints hints = new RenderingHints(
                    RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
            g2d.setRenderingHints(hints);
            g2d.setColor(Color.RED);
            drawShape(g2d, 5, 5);
            g2d.dispose();
            g2d = (Graphics2D) g.create();
            g2d.setColor(Color.BLUE);
            drawShape(g2d, 110, 5);
            g2d.dispose();
        }

        protected void drawShape(Graphics2D g2d, int x, int y) {
            g2d.draw(new Ellipse2D.Float(x, y, 100, 100));
        }
    }
}

更新了新示例

我使用的技巧之一是，我不使用“setShape”，而是简单地制作一个透明窗口并使用自定义面板为我提供我想要使用的形状。

与此相关的主要问题是，您现在要负责确保将内容绘制在形状内...

public class ShapedWindow {

    public static void main(String[] args) {
        new ShapedWindow();
    }

    public ShapedWindow() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                }

                JWindow frame = new JWindow();
                frame.setBackground(new Color(0, 0, 0, 0));
                frame.setContentPane(new ShapedPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
                frame.setAlwaysOnTop(true);
            }
        });
    }

    public class ShapedPane extends JPanel {

        public ShapedPane() {

            setOpaque(false);
            setLayout(new GridBagLayout());

            JButton button = new JButton("Close");
            button.addActionListener(new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    System.exit(0);
                }
            });

            add(button);

        }

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(200, 200);
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g); //To change body of generated methods, choose Tools | Templates.
            Graphics2D g2d = (Graphics2D) g.create();
            RenderingHints hints = new RenderingHints(
                    RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
            g2d.setRenderingHints(hints);
            g2d.setColor(getBackground());
            g2d.fill(new Ellipse2D.Float(0, 0, getWidth(), getHeight()));
            g2d.dispose();
        }
    }

}