pip install Spire.XLS

from spire.xls import *
from spire.xls.common import *

# Create a Workbook object
workbook = Workbook()

# Load an Excel document
workbook.LoadFromFile("C:\\Users\\Administrator\\Desktop\\Input.xlsx")

# Get a specific worksheet
worksheet = workbook.Worksheets[0]

# Get a cell range
range = worksheet.Range["D2:G13"]

# Convert text to number
range.ConvertToNumber()

# Save the workbook to a different Excel file
workbook.SaveToFile("output/TextToNumbers.xlsx", ExcelVersion.Version2013)

# Dispose resources
workbook.Dispose()

from spire.xls import *
from spire.xls.common import *

# Create a Workbook object
workbook = Workbook()

# Load an Excel document
workbook.LoadFromFile("C:\\Users\\Administrator\\Desktop\\Employee.xlsx")

# Get a specific worksheet
worksheet = workbook.Worksheets[0]

# Get a cell range
cellRange = worksheet.Range["F2:F9"]

# Convert numbers in the cell range to text
cellRange.NumberFormat = "@"

# Save the workbook to a different Excel file
workbook.SaveToFile("output/NumbersToText.xlsx", ExcelVersion.Version2013)

# Dispose resources
workbook.Dispose()

pip install Spire.PDF

from spire.pdf.common import *
from spire.pdf import *

# Create a PdfDocument object
pdf = PdfDocument()

# Load a PDF file from disk
pdf.LoadFromFile("Sample1.pdf")

# Get the first page
page = pdf.Pages[0]

# Crop the page by the specified area
page.CropBox = RectangleF(0.0, 300.0, 600.0, 260.0)

# Save the result file
pdf.SaveToFile("CropPDF.pdf")
pdf.Close()

from spire.pdf.common import *
from spire.pdf import *

# Create a PdfDocument object
pdf = PdfDocument()

# Load a PDF file from disk
pdf.LoadFromFile("Sample1.pdf")

# Get the first page
page = pdf.Pages[0]

# Crop the page by the specified area
page.CropBox = RectangleF(0.0, 300.0, 600.0, 260.0)

# Convert the page to an image
with pdf.SaveAsImage(0) as imageS:

    # Save the image as a PNG file
    imageS.Save("CropPDFSaveAsImage.png")
pdf.Close()

PM> Install-Package Spire.PDF

using System.Drawing;
using Spire.Pdf;

namespace CropPDFPage
{
    class Program
    {
        static void Main(string[] args)
        {
            //Create a PdfDocument object
            PdfDocument pdf = new PdfDocument();

            //Load a PDF file from disk
            pdf.LoadFromFile("Sample1.pdf");

            //Get the first page
            PdfPageBase page = pdf.Pages[0];

            //Crop the page by the specified area
            page.CropBox = new RectangleF(0, 300, 600, 260);

            //Save the result file
            pdf.SaveToFile("CropPDF.pdf");
            pdf.Close();
        }
    }
}

using System.Drawing;
using System.Drawing.Imaging;
using Spire.Pdf;
using Spire.Pdf.Graphics;

namespace CropPDFPageToImage
{
    class Program
    {
        static void Main(string[] args)
        {
            //Create a PdfDocument object
            PdfDocument pdf = new PdfDocument();

            //Load a PDF file from disk
            pdf.LoadFromFile("Sample1.pdf");

            //Get the first page
            PdfPageBase page = pdf.Pages[0];

            //Crop the page by the specified area
            page.CropBox = new RectangleF(0, 300, 600, 260);

            //Convert the page to an image
            Image image = pdf.SaveAsImage(0, PdfImageType.Bitmap);

            //Save the image as a PNG file
            image.Save("CropPDFSaveAsImage.png", ImageFormat.Png);

            //Save the image as a JPG file
            //image.Save("ToJPG.jpg", ImageFormat.Jpeg);

            //Save the image as a BMP file
            //image.Save("ToBMP.bmp", ImageFormat.Bmp);
        }
    }
}

<repositories>
    <repository>
        <id>com.e-iceblue</id>
        <name>e-iceblue</name>
        <url>https://repo.e-iceblue.com/nexus/content/groups/public/</url>
    </repository>
</repositories>
<dependencies>
    <dependency>
        <groupId>e-iceblue</groupId>
        <artifactId>spire.pdf</artifactId>
        <version>10.10.7</version>
    </dependency>
</dependencies>
    

import com.spire.pdf.PdfDocument;
import com.spire.pdf.fields.PdfField;
import com.spire.pdf.security.PdfSignature;
import com.spire.pdf.widget.PdfFormWidget;
import com.spire.pdf.widget.PdfSignatureFieldWidget;

public class VerifySignature {
    public static void main(String[] args) {
        // Create a PdfDocument object
        PdfDocument pdf = new PdfDocument();
        // Load a PDF document
        pdf.loadFromFile("Signature.pdf");

        // Get the form of the PDF document
        PdfFormWidget formWidget = (PdfFormWidget) pdf.getForm();

        if(formWidget.getFieldsWidget().getCount() > 0)
        {
            // Iterate through all fields in the form
            for(int i = 0; i < formWidget.getFieldsWidget().getCount(); i ++)
            {
                PdfField field = formWidget.getFieldsWidget().get(i);
                // Find the signature field
                if (field instanceof PdfSignatureFieldWidget)
                {
                    PdfSignatureFieldWidget signatureField = (PdfSignatureFieldWidget) field;
                    // Get the signature
                    PdfSignature signature = signatureField.getSignature();
                    // Verify the signature
                    boolean valid = signature.verifySignature();
                    if(valid)
                    {
                      System.out.print("The signature is valid!");
                    }
                    else
                    {
                        System.out.print("The signature is invalid!");
                    }
                }
            }
        }
    }
}

import com.spire.pdf.PdfDocument;
import com.spire.pdf.fields.PdfField;
import com.spire.pdf.security.PdfSignature;
import com.spire.pdf.widget.PdfFormWidget;
import com.spire.pdf.widget.PdfSignatureFieldWidget;

public class CheckIfSignedPdfIsModified {
    public static void main(String[] args) {
        // Create a PdfDocument object
        PdfDocument pdf = new PdfDocument();
        // Load a PDF document
        pdf.loadFromFile("Signature.pdf");

        // Get the form of the PDF document
        PdfFormWidget formWidget = (PdfFormWidget) pdf.getForm();

        if(formWidget.getFieldsWidget().getCount() > 0) {
            // Iterate through all fields in the form
            for (int i = 0; i < formWidget.getFieldsWidget().getCount(); i++) {
                PdfField field = formWidget.getFieldsWidget().get(i);
                // Find the signature field
                if (field instanceof PdfSignatureFieldWidget) {
                    PdfSignatureFieldWidget signatureField = (PdfSignatureFieldWidget) field;
                    // Get the signature
                    PdfSignature signature = signatureField.getSignature();
                    // Verify the signaure
                    boolean modified = signature.verifyDocModified();
                    if(modified)
                    {
                        System.out.print("The document has been modified!");
                    }
                    else
                    {
                        System.out.print("The document has not been modified!");
                    }
                }
            }
        }
    }
}

import com.spire.pdf.PdfDocument;
import com.spire.pdf.fields.PdfField;
import com.spire.pdf.security.PdfCertificate;
import com.spire.pdf.security.PdfSignature;
import com.spire.pdf.widget.PdfFormWidget;
import com.spire.pdf.widget.PdfSignatureFieldWidget;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;

public class ExtractSignatureImage {
    public static void main(String[] args) {
        // Create a PdfDocument object
        PdfDocument pdf = new PdfDocument();
        // Load a PDF document
        pdf.loadFromFile("Signature.pdf");

        // Get the form of the PDF document
        PdfFormWidget formWidget = (PdfFormWidget) pdf.getForm();

        // Extract signature images
        Image[] images = formWidget.extractSignatureAsImages();
        // Iterate through the images and save each image to file
        for (int i = 0; i < images.length; i++) {
            try {
                // Convert the Image to BufferedImage
                BufferedImage bufferedImage = (BufferedImage) images[i];
                // Define the output file path
                File outputFile = new File("output\\signature_" + i + ".png");
                // Save the image as a PNG file
                ImageIO.write(bufferedImage, "png", outputFile);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        // Create a text file to save the certificate information
        try (BufferedWriter writer = new BufferedWriter(new FileWriter("output\\certificate_info.txt"))) {
            if (formWidget.getFieldsWidget().getCount() > 0) {
                // Iterate through all fields in the form
                for (int i = 0; i < formWidget.getFieldsWidget().getCount(); i++) {
                    PdfField field = formWidget.getFieldsWidget().get(i);
                    // Find the signature field
                    if (field instanceof PdfSignatureFieldWidget) {
                        PdfSignatureFieldWidget signatureField = (PdfSignatureFieldWidget) field;
                        // Get the signature
                        PdfSignature signature = signatureField.getSignature();

                        // Get the certificate info of the signature
                        String certificateInfo = signature.getCertificate() != null ? signature.getCertificate().toString() : "No certificate";

                        // Write the certificate information to the text file
                        writer.write("Certificate Info: \n" + certificateInfo);
                        writer.write("-----------------------------------\n");
                    }
                }
            } else {
                writer.write("No signature fields found.");
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

<repositories>
    <repository>
        <id>com.e-iceblue</id>
        <name>e-iceblue</name>
        <url>https://repo.e-iceblue.cn/repository/maven-public/</url>
    </repository>
</repositories>
<dependencies>
    <dependency>
        <groupId>e-iceblue</groupId>
        <artifactId>spire.ocr</artifactId>
        <version>1.9.19</version>
    </dependency>
</dependencies>

import com.spire.ocr.*;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;

public class Main {
    public static void main(String[] args) {
        try {
            // Create an instance of the OcrScanner class
            OcrScanner scanner = new OcrScanner();

            // Create an instance of the ConfigureOptions class to set up the scanner configurations
            ConfigureOptions configureOptions = new ConfigureOptions();

            // Set the path to the new model
            configureOptions.setModelPath("D:\\win-x64");

            // Set the language for text recognition. The default is English.
            // Supported languages include English, Chinese, Chinesetraditional, French, German, Japanese, and Korean.
            configureOptions.setLanguage("English");

            // Apply the configuration options to the scanner
            scanner.ConfigureDependencies(configureOptions);

            // Extract text from an image
            scanner.scan("Sample.png");

            // Save the extracted text to a text file
            saveTextToFile(scanner, "output.txt");

        } catch (OcrException e) {
            e.printStackTrace();
        }
    }

    private static void saveTextToFile(OcrScanner scanner, String filePath) {
        try {
            String text = scanner.getText().toString();
            try (BufferedWriter writer = new BufferedWriter(new FileWriter(filePath))) {
                writer.write(text);
            }
        } catch (IOException | OcrException e) {
            e.printStackTrace();
        }
    }
}