Java 屏幕截图应用程序 - 如何？

Question

我的母语不是英语，所以首先对语法感到抱歉。

我想做一个应用程序来捕获屏幕的选定区域并保存它。我做了一些研究，并在下面编写了代码。

我的问题是:

1 - 我如何在此应用程序中打开 pdf 文件？ (我尝试使用一种方法，但它不起作用。我不知道到底把它放在代码中的哪里)

2 - 如何将选定区域保存到新文件中？ (图像文件:JPEG、JPG、png)

3 - [复杂部分] 现在，代码每次仅“保存”一个选定区域。我想捕获屏幕的很多部分并将其保存在同一个图像文件中。一个挨着另一个。我怎样才能做到这一点 ？

Java 代码:

package javaapplication39;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import javax.swing.*;

public class ScreenCaptureRectangle {

    Rectangle captureRect;

    ScreenCaptureRectangle(final BufferedImage screen) {
        final BufferedImage screenCopy = new BufferedImage(
                screen.getWidth(),
                screen.getHeight(),
                screen.getType());
        final JLabel screenLabel = new JLabel(new ImageIcon(screenCopy));
        JScrollPane screenScroll = new JScrollPane(screenLabel);

        screenScroll.setPreferredSize(new Dimension(
                (int)(screen.getWidth()/3),
                (int)(screen.getHeight()/3)));

        JPanel panel = new JPanel(new BorderLayout());
        panel.add(screenScroll, BorderLayout.CENTER);

        final JLabel selectionLabel = new JLabel(
                "Drag a rectangle in the screen shot!");
        panel.add(selectionLabel, BorderLayout.SOUTH);

        repaint(screen, screenCopy);
        screenLabel.repaint();

        screenLabel.addMouseMotionListener(new MouseMotionAdapter() {

            Point start = new Point();

            @Override
            public void mouseMoved(MouseEvent me) {
                start = me.getPoint();
                repaint(screen, screenCopy);
                selectionLabel.setText("Start Point: " + start);
                screenLabel.repaint();
            }

            @Override
            public void mouseDragged(MouseEvent me) {
                Point end = me.getPoint();
                captureRect = new Rectangle(start,
                        new Dimension(end.x-start.x, end.y-start.y));
                repaint(screen, screenCopy);
                screenLabel.repaint();
                selectionLabel.setText("Rectangle: " + captureRect);
            }
        });

        JOptionPane.showMessageDialog(null, panel);

        System.out.println("Rectangle of interest: " + captureRect);
    }

    public void repaint(BufferedImage orig, BufferedImage copy) {
        Graphics2D g = copy.createGraphics();
        g.drawImage(orig,0,0, null);
        if (captureRect!=null) {
            g.setColor(Color.RED);
            g.draw(captureRect);
            g.setColor(new Color(255,255,255,150));
            g.fill(captureRect);
        }
        g.dispose();
    }

    public static void main(String[] args) throws Exception {
        Robot robot = new Robot();
        final Dimension screenSize = Toolkit.getDefaultToolkit().
                getScreenSize();
        final BufferedImage screen = robot.createScreenCapture(
                new Rectangle(screenSize));

        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                new ScreenCaptureRectangle(screen);
            }
        });
    }
}

Answer 1

1 - How can i open a pdf file in this app ? (i tried use a method but it didnt work. I dont know exactly where to put it on the code)

看看How to Integrate with the Desktop Class

2 - How can i save the selected area in a new file ? (a image file : JPEG, JPG,png)

看看Writing/Saving an Image

3 - [the complex part] right now, the code only "save" one selected area each time. I want to capture a lot of parts of screen and save this in the same image file. one beside the other. How can i do this ?

正如您所说，这是一个更复杂的问题。您必须修改代码，以便在 JFrame 中显示面板，而不是在 JOptionPane 中显示 panel，然后您需要能够监视 mouseReleaseEvent 或提供某种操作(可能是工具栏或菜单选项)，允许用户保存选择。

看看How to Use Menus , How to Use Buttons, Check Boxes, and Radio Buttons , How to Write an Action Listeners和 How to Use Tool Bars了解更多详情。

顺便说一句，代码只允许您捕获单个屏幕，您可能会考虑类似 Drawing a bounding rectangle to select what area to record 的内容。这将允许您捕获整个虚拟桌面(多个屏幕)