Java 圆圈中的圆圈淡出，创建目标

我想创建一个图形，使圆圈重叠，颜色淡出，并且圆圈之间应该有一个空白，类似于此：

以下是我所取得的成绩：

import java.awt.*;
import java.awt.geom.*;
import javax.swing.*;
import java.awt.event.MouseListener;
import java.awt.event.MouseEvent;

class Circles extends JPanel implements MouseListener {


    public void mouseReleased(MouseEvent event) {

    }
    public void mousePressed(MouseEvent event) {

    }
    public void mouseClicked(MouseEvent event) {

    }
    public void mouseEntered(MouseEvent event) {}
    public void mouseExited(MouseEvent event) {}


    public Circles() {
        addMouseListener(this);
    }


    public void paint(Graphics g) {
        g.setColor(Color.white);
        int w = getWidth();
        int h = getHeight();
        g.fillRect(0, 0, w, h);


        Graphics2D g2 = (Graphics2D) g;

        for (int i = 0; i < 20; i++) {
            if (i % 2 == 0) {
                Color c = new Color(255 - i * 10, 255 - i * 10, 255 - i * 10);
                g2.setColor(c);
            } else {
                g2.setColor(Color.white);
            }

            g2.fillOval((5 * i), (5 * i), (w - 10) * i, (h - 10) * i);
        }
    }

    public static void main(String[] args) {
        Frame w = new Frame();
        w.setVisible(true);
    }
}

---

有很多方法可以实现这一点，但首先，先覆盖

paintComponent

，而不是

paint

其次，您需要某种循环，在每次迭代中扩展圆的半径

第三，您需要一个简单的

int

值，该值作为alpha值，从255开始，降低到您想要的最微弱的alpha值，例如64

在循环的每次迭代中，您都希望增加半径值，并相应地减少alpha值。然后，您只需使用所需的RGB和alpha值创建一个新的

Color

对象

查看详细信息

用示例更新…

import java.awt.BasicStroke;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.geom.Ellipse2D;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class FadingCircles {

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

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

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

        });
    }

    public static class TestPane extends JPanel {

        public static final int CIRCLE_COUNT = 10;

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

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            Graphics2D g2d = (Graphics2D) g.create();

            g2d.setRenderingHint(RenderingHints.KEY_ALPHA_INTERPOLATION, RenderingHints.VALUE_ALPHA_INTERPOLATION_QUALITY);
            g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
            g2d.setRenderingHint(RenderingHints.KEY_COLOR_RENDERING, RenderingHints.VALUE_COLOR_RENDER_QUALITY);
            g2d.setRenderingHint(RenderingHints.KEY_DITHERING, RenderingHints.VALUE_DITHER_ENABLE);
            g2d.setRenderingHint(RenderingHints.KEY_FRACTIONALMETRICS, RenderingHints.VALUE_FRACTIONALMETRICS_ON);
            g2d.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
            g2d.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
            g2d.setRenderingHint(RenderingHints.KEY_STROKE_CONTROL, RenderingHints.VALUE_STROKE_PURE);

            int maxRadius = Math.min(getWidth(), getHeight());
            int alpha = 255;
            int range = 255 - 32;
            g2d.setStroke(new BasicStroke(6, BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND));

            for (int index = 0; index < CIRCLE_COUNT; index++) {
                float progress = (float) index / (float) CIRCLE_COUNT;
                alpha = 255 - Math.round(range * progress);
                Color color = new Color(0, 0, 0, alpha);
                g2d.setColor(color);

                int radius = Math.round(maxRadius * progress);
                int x = (getWidth() - radius) / 2;
                int y = (getHeight() - radius) / 2;

                g2d.draw(new Ellipse2D.Float(x, y, radius, radius));
            }
            g2d.dispose();
        }
    }
}

import java.awt.BasicStroke；
导入java.awt.BorderLayout；
导入java.awt.Color；
导入java.awt.Dimension；
导入java.awt.EventQueue；
导入java.awt.Graphics；
导入java.awt.Graphics2D；
导入java.awt.RenderingHints；
导入java.awt.geom.Ellipse2D；
导入javax.swing.JFrame；
导入javax.swing.JPanel；
导入javax.swing.UIManager；
导入javax.swing.UnsupportedLookAndFeelException；
公共类渐消圈{
公共静态void main（字符串[]args）{
新的渐消圈（）；
}
公众时尚圈（）{
invokeLater（新的Runnable（）{
@凌驾
公开募捐{
试一试{
UIManager.setLookAndFeel（UIManager.getSystemLookAndFeelClassName（））；
}catch（ClassNotFoundException |实例化Exception | IllegalacessException |不支持ookandfeelException ex）{
}
JFrame=新JFrame（“测试”）；
frame.setDefaultCloseOperation（JFrame.EXIT_ON_CLOSE）；
frame.setLayout（新的BorderLayout（））；
frame.add（newtestpane（））；
frame.pack（）；
frame.setLocationRelativeTo（空）；
frame.setVisible（true）；
}
});
}
公共静态类TestPane扩展了JPanel{
公共静态最终整数循环计数=10；
@凌驾
公共维度getPreferredSize（）{
返回新维度（200200）；
}
@凌驾
受保护组件（图形g）{
超级组件（g）；
Graphics2D g2d=（Graphics2D）g.create（）；
g2d.setRenderingHint（RenderingHits.KEY\u ALPHA\u插值，RenderingHits.VALUE\u ALPHA\u插值\u质量）；
g2d.setRenderingHint（renderingHits.KEY\u抗锯齿，renderingHits.VALUE\u抗锯齿\u开启）；
g2d.setRenderingHint（RenderingHints.KEY\u COLOR\u RENDERING，RenderingHints.VALUE\u COLOR\u RENDER\u QUALITY）；
g2d.setRenderingHint（renderingHits.KEY\u抖动，renderingHits.VALUE\u抖动\u启用）；
g2d.setRenderingHint（renderingHits.KEY_分数矩阵，renderingHits.VALUE_分数矩阵开）；
g2d.setRenderingHint（RenderingHits.KEY\u插值，RenderingHits.VALUE\u插值\u双线性）；
g2d.setRenderingHint（renderingHits.KEY_RENDERING，renderingHits.VALUE_RENDER_QUALITY）；
g2d.setRenderingHint（renderingHits.KEY\u STROKE\u控件，renderingHits.VALUE\u STROKE\u PURE）；
int maxRadius=Math.min（getWidth（），getHeight（））；
int alpha=255；
整数范围=255-32；
g2d.设定行程（新基本行程（6，基本行程。循环，基本行程。加入循环））；
对于（int index=0；index

---

您可能还想签出

您想创建一个

目标

？您可能会在这里得到您想要的：非常感谢您的解释。

import java.awt.BasicStroke;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.geom.Ellipse2D;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class FadingCircles {

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

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

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

        });
    }

    public static class TestPane extends JPanel {

        public static final int CIRCLE_COUNT = 10;

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

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            Graphics2D g2d = (Graphics2D) g.create();

            g2d.setRenderingHint(RenderingHints.KEY_ALPHA_INTERPOLATION, RenderingHints.VALUE_ALPHA_INTERPOLATION_QUALITY);
            g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
            g2d.setRenderingHint(RenderingHints.KEY_COLOR_RENDERING, RenderingHints.VALUE_COLOR_RENDER_QUALITY);
            g2d.setRenderingHint(RenderingHints.KEY_DITHERING, RenderingHints.VALUE_DITHER_ENABLE);
            g2d.setRenderingHint(RenderingHints.KEY_FRACTIONALMETRICS, RenderingHints.VALUE_FRACTIONALMETRICS_ON);
            g2d.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
            g2d.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
            g2d.setRenderingHint(RenderingHints.KEY_STROKE_CONTROL, RenderingHints.VALUE_STROKE_PURE);

            int maxRadius = Math.min(getWidth(), getHeight());
            int alpha = 255;
            int range = 255 - 32;
            g2d.setStroke(new BasicStroke(6, BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND));

            for (int index = 0; index < CIRCLE_COUNT; index++) {
                float progress = (float) index / (float) CIRCLE_COUNT;
                alpha = 255 - Math.round(range * progress);
                Color color = new Color(0, 0, 0, alpha);
                g2d.setColor(color);

                int radius = Math.round(maxRadius * progress);
                int x = (getWidth() - radius) / 2;
                int y = (getHeight() - radius) / 2;

                g2d.draw(new Ellipse2D.Float(x, y, radius, radius));
            }
            g2d.dispose();
        }
    }
}