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java - 如何在透明窗口上绘制图像?

转载 作者:塔克拉玛干 更新时间:2023-11-01 21:56:03 25 4
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我正在尝试在 JFrame 上使用 Graphics2D 绘制图像。
但是这段代码只显示空白背景。
怎么做?

Java版本:SE-1.6
集成开发环境:Eclipse

我的代码是这样的:

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.image.BufferStrategy;
import java.awt.geom.Line2D;
import java.util.TimerTask;

import javax.swing.JFrame;

public class GraphicTest extends JFrame{

public static void main(String[] args) {
GraphicTest gt = new GraphicTest();
gt.start();
}

JFrame frame;
BufferStrategy strategy;

GraphicTest(){
int width = 320;
int height = 240;

this.frame = new JFrame("test");

this.frame.setSize(width, height);
this.frame.setLocationRelativeTo(null);
this.frame.setLocation(576, 336);
this.frame.setDefaultCloseOperation(javax.swing.JFrame.EXIT_ON_CLOSE);

this.frame.setUndecorated(true);
this.frame.setBackground(new Color(0, 0, 0, 50));

this.frame.setVisible(true);

this.frame.setIgnoreRepaint(true);
this.frame.createBufferStrategy(2);
this.strategy = this.frame.getBufferStrategy();
}

public void onExit(){
System.exit(0);
}

void start(){
java.util.Timer timer = new java.util.Timer();
timer.schedule(new RenderTask(), 0, 16);
}

class RenderTask extends TimerTask{
int count = 0;

@Override
public void run() {
GraphicTest.this.render();
}
}

void render() {
// Some moving images
Graphics2D g2 = (Graphics2D)this.strategy.getDrawGraphics();
g2.setStroke(new BasicStroke(5.0f));
Line2D line = new Line2D.Double(20, 40, 120, 140);
g2.draw(line);
this.strategy.show();
}
}

感谢您提供的任何帮助。

最佳答案

  • BufferStrategy 通常与没有任何透明度概念的重量级组件相关联。
  • Java 6 不“官方”支持透明和半透明(每个 alpha 像素)
  • 使窗口半透明会影响任何其他绘制在它上面的东西......这非常烦人,无论您使用的是 Java 6 还是 Java 7

秘诀是首先让 Window 透明,然后覆盖一个具有特殊“半透明”绘画效果的透明组件。

在 Java 6(我认为是更新 10)下,有一个名为 AWTUtilities 的私有(private) API 可用,它提供了使窗口透明或半透明的能力,以下示例基于该 API。

Bouncy Birdy

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.Window;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.lang.reflect.Method;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class TransparentWindowAnimation {

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

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

if (supportsPerAlphaPixel()) {
try {
JFrame frame = new JFrame("Testing");
frame.setUndecorated(true);
setOpaque(frame, false);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new PaintPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
} catch (Exception exp) {
exp.printStackTrace();
}
} else {
System.err.println("Per pixel alphering is not supported");
}
}
});
}

public static boolean supportsPerAlphaPixel() {
boolean support = false;
try {
Class<?> awtUtilsClass = Class.forName("com.sun.awt.AWTUtilities");
support = true;
} catch (Exception exp) {
}
return support;
}

public static void setOpaque(Window window, boolean opaque) throws Exception {
try {
Class<?> awtUtilsClass = Class.forName("com.sun.awt.AWTUtilities");
if (awtUtilsClass != null) {
Method method = awtUtilsClass.getMethod("setWindowOpaque", Window.class, boolean.class);
method.invoke(null, window, opaque);
}
} catch (Exception exp) {
throw new Exception("Window opacity not supported");
}
}

public class PaintPane extends JPanel {

private BufferedImage img;

private int xPos, yPos = 100;
private int xDelta = 0;
private int yDelta = 0;

public PaintPane() {
while (xDelta == 0) {
xDelta = (int)((Math.random() * 8)) - 4;
}
while (yDelta == 0) {
yDelta = (int)((Math.random() * 8)) - 4;
}
setOpaque(false);
try {
img = ImageIO.read(new File("AngryBird.png"));
} catch (IOException ex) {
ex.printStackTrace();
}

Timer timer = new Timer(40, new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
xPos += xDelta;
yPos += yDelta;
if (xPos - (img.getWidth() / 2) <= 0) {
xPos = img.getWidth() / 2;
xDelta *= -1;
}
if (xPos + (img.getWidth() / 2) >= getWidth()) {
xPos = getWidth() - (img.getWidth() / 2);
xDelta *= -1;
}
if (yPos - (img.getHeight() / 2) <= 0) {
yPos = img.getHeight() / 2;
yDelta *= -1;
}
if (yPos + (img.getHeight() / 2) >= getHeight()) {
yPos = getHeight() - (img.getHeight() / 2);
yDelta *= -1;
}
repaint();
}
});
timer.start();
}

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

@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
g2d.setColor(new Color(128, 128, 128, 128));
g2d.fillRect(0, 0, getWidth(), getHeight());
int x = xPos - (img.getWidth() / 2);
int y = yPos - (img.getHeight()/ 2);
g2d.drawImage(img, x, y, this);
g2d.dispose();
}
}

}

关于java - 如何在透明窗口上绘制图像?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/21771215/

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