如何使用java捕获某些应用程序的屏幕？

Question

我发现java awt可以截取全屏，但是如何截取特定应用程序的屏幕呢？比如我打开了一个matlab应用和eclipse应用。而且我无法告诉程序应用程序屏幕的大小，只知道 matlab 现在是一个活动窗口。我只想捕获 Matlab 的屏幕。我该怎么做？

import java.awt.AWTException; 
import java.awt.Rectangle; 
import java.awt.Toolkit; 
import java.awt.Robot; 
import java.awt.image.BufferedImage; 
import java.io.IOException; 
import java.io.File; 
import javax.imageio.ImageIO; 
  
public class Screenshot { 
    public static final long serialVersionUID = 1L; 
    public static void main(String[] args) 
    { 
        try { 
            Thread.sleep(120); 
            Robot r = new Robot(); 
  
            // It saves screenshot to desired path 
            String path = "D:// Shot.jpg"; 
  
            // Used to get ScreenSize and capture image 
            Rectangle capture =  
            new Rectangle(Toolkit.getDefaultToolkit().getScreenSize()); 
            BufferedImage Image = r.createScreenCapture(capture); 
            ImageIO.write(Image, "jpg", new File(path)); 
            System.out.println("Screenshot saved"); 
        } 
        catch (AWTException | IOException | InterruptedException ex) { 
            System.out.println(ex); 
        } 
    } 
} 

Answer 1

要截取屏幕的一部分，我们需要指定一个要截取的矩形区域。以下语句创建一个截取区域，即屏幕的前四分之一。

try {
            Robot robot = new Robot();
            String format = "jpg";
            String fileName = "PartialScreenshot." + format;
             
            Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
            Rectangle captureRect = new Rectangle(0, 0, screenSize.width / 2, screenSize.height / 2);
            BufferedImage screenFullImage = robot.createScreenCapture(captureRect);
            ImageIO.write(screenFullImage, format, new File(fileName));
             
            System.out.println("A partial screenshot saved!");
        } catch (AWTException | IOException ex) {
            System.err.println(ex);
        }