java - 如何从基于 SWT 的应用程序打印 SWT 窗口的屏幕

Question

我想允许用户打印她或他与之交互的应用程序窗口。我正在寻找如何为基于 SWT 的 GUI 实现这种打印屏幕功能的示例。

Answer 1

一个非常简单的方法是(我们在我们的产品中使用)截取窗口的屏幕截图，然后使用 SWT 打印机 API 打印它。

请参阅下面的代码获取窗口的屏幕截图。

>> 原始窗口

>>屏幕截图

>>代码

该代码仅说明特定窗口的屏幕捕获。在此处检查打印机 api 的使用情况 SWT Printer Usage 。在这段代码中，我为显示创建了一个 GC，然后复制了 shell 所在的区域。

import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.StyleRange;
import org.eclipse.swt.custom.StyledText;
import org.eclipse.swt.events.PaintEvent;
import org.eclipse.swt.events.PaintListener;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Canvas;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Table;
import org.eclipse.swt.widgets.TableColumn;
import org.eclipse.swt.widgets.TableItem;

public class ScreenCaptureTest 
{
    public static void main(String[] args) 
    {
        String[] names  = {"Harry", "Sally", "Jhon", "Tim", "Scott"};
        String[] msg    = {"Hello World!", "Today is a nice day to walk", "I am bored", "This is how you take widget capture", "Ha Ha Ha!! That's funny !"}; 

        final Display display = new Display();
        final Shell shell = new Shell(display);
        shell.setText("Screen Capture");
        shell.setLayout(new GridLayout(1, true));

        final Composite composite = new Composite(shell, SWT.BORDER);
        composite.setLayout(new GridLayout(2, true));
        composite.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));


        /*
         * Create Table Widget
         */

        Table table = new Table(composite, SWT.BORDER|SWT.V_SCROLL|SWT.H_SCROLL|SWT.FULL_SELECTION);

        table.setLinesVisible(true);
        table.setHeaderVisible(true);

        table.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));

        TableColumn columnName = new TableColumn(table, SWT.LEFT);
        columnName.setText("Name");
        columnName.setWidth(100);

        TableColumn columnMsg = new TableColumn(table, SWT.LEFT);
        columnMsg.setText("Message");
        columnMsg.setWidth(200);

        for (int i = 0; i < 5; i++) 
        {
            TableItem item = new TableItem(table, SWT.NONE, 0);
            item.setText(0, names[i]);
            item.setText(1, msg[i]);            
        }

        /*
         * Create StyledText Widget
         */

        StyledText text = new StyledText (composite, SWT.BORDER);
        text.setText("0123456789 ABCDEFGHIJKLM NOPQRSTUVWXYZ");
        text.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));

        StyleRange style1 = new StyleRange();
        style1.start = 0;
        style1.length = 10;
        style1.fontStyle = SWT.BOLD;
        text.setStyleRange(style1);

        StyleRange style2 = new StyleRange();
        style2.start = 11;
        style2.length = 13;
        style2.foreground = display.getSystemColor(SWT.COLOR_RED);
        text.setStyleRange(style2);

        StyleRange style3 = new StyleRange();
        style3.start = 25;
        style3.length = 13;
        style3.background = display.getSystemColor(SWT.COLOR_BLUE);
        text.setStyleRange(style3);

        /*
         * Create Button
         */

        Button button = new Button(shell, SWT.PUSH);
        button.setText("Capture");
        button.pack();

        button.addListener(SWT.Selection, new Listener()
        {
            public void handleEvent(Event event) 
            {
                /*
                 * Widget capturing logic
                 */
                GC gc = new GC(display);
                final Image image = new Image(display, shell.getBounds());
                gc.copyArea(image, shell.getBounds().x, shell.getBounds().y);
                gc.dispose();

                Shell popup = new Shell(shell);
                popup.setText("Captured Image");
                popup.addListener(SWT.Close, new Listener() {
                    public void handleEvent(Event e) {
                        image.dispose();
                    }
                });

                Canvas canvas = new Canvas(popup, SWT.NONE);
                canvas.setBounds(0,0,image.getImageData().width, image.getImageData().height);
                canvas.addPaintListener(new PaintListener() {
                    public void paintControl(PaintEvent e) {
                        e.gc.drawImage(image, 0, 0);
                    }
                });
                popup.pack();
                popup.open();
            }
        });

        shell.pack();
        shell.open();

        while (!shell.isDisposed()) {
            if (!display.readAndDispatch())
                display.sleep();
        }

        display.dispose();
    }
}