如何将带有可滚动的JPanel导出到pdf文件中

我设计了一个带有可滚动function的摇摆组件的jpanel。 我想将整个Jpanle导出为pdf文件。但我无法导出整个Jpanle。 我使用itext进行pdf生成。 我的问题是我无法将整个jpanel导出为pdf。 当我导出一半的Jpanel组件导出。但是一半的部分不导出。 这是我的代码。

public void PrintFrameToPDF(JPanel c, File file) { try { Document d = new Document(); PdfWriter writer = PdfWriter.getInstance(d, new FileOutputStream("F://newfile.pdf")); d.open(); PdfContentByte cb = writer.getDirectContent(); PdfTemplate template = cb.createTemplate(800, 1600); Graphics2D g2d = template.createGraphics(800, 1600); // g2d.translate(1.0, 1.0); c.paintAll(g2d); // c.addNotify(); // c.validate(); g2d.dispose(); cb.addTemplate(template, 0, 0); d.close(); } catch (Exception e) { // } } 

请帮助我。 TNX

Answer 1

考虑首先从面板创建一个java.awt.Image （通过将面板绘制到一个Image）。 然后，您可以使用以下命令获取com.itextpdf.text.Image的实例：

com.itextpdf.text.Image.getInstance(PdfWriter writer, java.awt.Image awtImage, float quality) –
从java.awt.Image获取com.itextpdf.textImage的实例。 图像以JPEG格式添加，具有用户定义的质量。

然后，您可以使用com.itextpdf.text.Image API方法scaleToFit或scalePercent() （在下面的示例中使用scalePercent()来缩放图像。 有关使用图像的更多信息（在iText中）可以在这里找到

以下程序创建一个大小为2000×2000的面板，其中正方形20×20（每个100px）被绘制到面板上。 面板包含在滚动窗格内。 然后将其绘制到图像上，图像将缩放并添加到pdf文档并打印为pdf。

_{下图仅显示如何将整个面板绘制到图像上，然后使用前一个面板图像创建另一个面板以绘制到新面板上。 然后通过对话框显示新面板。}

 import java.awt.Color; import java.awt.Component; import java.awt.Dimension; import java.awt.Graphics; import java.awt.image.BufferedImage; import java.io.FileOutputStream; import javax.swing.JFrame; import javax.swing.JOptionPane; import javax.swing.JPanel; import javax.swing.JScrollPane; import javax.swing.SwingUtilities; import com.itextpdf.text.Document; import com.itextpdf.text.Image; import com.itextpdf.text.pdf.PdfWriter; /** * This example requires iText. I retrieved it from Maven repository * *  * com.itextpdf * itextpdf * 5.5.2 *  * * The program can be run without iText if you comment out the entire * method printToPDF (and iText imports), along with it's method call in * the class constructor. The result will be the the image above. */ public class LargePanelToImageMCVE { public LargePanelToImageMCVE() { LargeImagePanel panel = new LargeImagePanel(); JFrame frame = new JFrame(); frame.add(new JScrollPane(panel)); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setExtendedState(JFrame.MAXIMIZED_BOTH); frame.setVisible(true); final java.awt.Image image = getImageFromPanel(panel); /* This was just a text panel to make sure the full panel was * drawn to the panel. */ JPanel newPanel = new JPanel() { @Override protected void paintComponent(Graphics g) { super.paintComponent(g); g.drawImage(image, 0, 0, getWidth(), getHeight(), this); } @Override public Dimension getPreferredSize() { return new Dimension(300, 300); } }; /* Print Image to PDF */ String fileName = "D://newfile.pdf"; printToPDF(image, fileName); /* This was just a test to show the newPanel drew the entire * original panel (scaled) */ JOptionPane.showMessageDialog(null, newPanel); } public void printToPDF(java.awt.Image awtImage, String fileName) { try { Document d = new Document(); PdfWriter writer = PdfWriter.getInstance(d, new FileOutputStream( fileName)); d.open(); Image iTextImage = Image.getInstance(writer, awtImage, 1); iTextImage.setAbsolutePosition(50, 50); iTextImage.scalePercent(25); d.add(iTextImage); d.close(); } catch (Exception e) { e.printStackTrace(); } } public static java.awt.Image getImageFromPanel(Component component) { BufferedImage image = new BufferedImage(component.getWidth(), component.getHeight(), BufferedImage.TYPE_INT_RGB); component.paint(image.getGraphics()); return image; } /** * Demo panel that is 2000x2000 px with alternating squares * to check all squares are drawn to image */ public class LargeImagePanel extends JPanel { private static final int FULL_SIZE = 2000; private static final int PER_ROW_COLUMN = 20; private static final int SQUARE_SIZE = FULL_SIZE / PER_ROW_COLUMN; protected void paintComponent(Graphics g) { super.paintComponent(g); for (int row = 0; row < PER_ROW_COLUMN; row++) { for (int col = 0; col < PER_ROW_COLUMN; col++) { if ((row % 2) == (col % 2)) { g.setColor(Color.BLACK); } else { g.setColor(Color.WHITE); } g.fillRect(col * SQUARE_SIZE, row * SQUARE_SIZE, SQUARE_SIZE, SQUARE_SIZE); } } } @Override public Dimension getPreferredSize() { return new Dimension(FULL_SIZE, FULL_SIZE); } } public static void main(String[] args) { SwingUtilities.invokeLater(new Runnable() { public void run() { new LargePanelToImageMCVE(); } }); } }