C#將圖像添加到PDF（開發者教程）

Create or Open C# Project

To add images to a PDF document, the latest version of Visual Studio is recommended for creating a C# project for a smooth experience.

• Open Visual Studio.

Visual Studio starting up UI

• Click on the "Create a New Project" button.
• Select "C# Console Application" from the Project templates and click on the Next button. You can choose a platform according to your needs.

Create a Console Application in Visual Studio

• Next, give a name to your project and click on the Next button.
• Choose Target .NET Framework >= .NET Core 3.1 version and click on the Create button.

By following the above steps, you will be able to create a new C# project easily. You can use an already existing C# project. Just open the project and install the IronPDF library.

Install the IronPDF Library

Install-Package IronPdf

using IronPdf;

using IronPdf;

Imports IronPdf

Adding Bitmaps and Images to the PDF Document

There are multiple ways to add images to PDF documents using IronPDF: use a direct image file, convert images to bytes, or use System.Drawing.Bitmap. Furthermore, the IronPDF library supports multiple image formats.

Let's take a look:

using IronPdf;
using System.IO;
using System.Drawing;

class PDFImageAdder
{
    /* This method demonstrates how to convert an image file to a PDF document in C# */
    static void Main(string[] args)
    {
        // Initialize IronPdf Renderer
        var renderer = new IronPdf.ChromePdfRenderer();

        // Read the PNG image file into binary format
        var pngBinaryData = File.ReadAllBytes("embed_me.png");

        // Convert image binary data to base64 for embedding in HTML
        var ImgDataURI = "data:image/png;base64," + Convert.ToBase64String(pngBinaryData);

        // Embed the image as a base64 data URI in an HTML <img> tag
        var ImgHtml = $"<img src='{ImgDataURI}'>";

        // Render the HTML as a PDF document
        using var pdfdoc = renderer.RenderHtmlAsPdf(ImgHtml);

        // Save the rendered PDF document
        pdfdoc.SaveAs("embedded_example_1.pdf");
    }
}

using IronPdf;
using System.IO;
using System.Drawing;

class PDFImageAdder
{
    /* This method demonstrates how to convert an image file to a PDF document in C# */
    static void Main(string[] args)
    {
        // Initialize IronPdf Renderer
        var renderer = new IronPdf.ChromePdfRenderer();

        // Read the PNG image file into binary format
        var pngBinaryData = File.ReadAllBytes("embed_me.png");

        // Convert image binary data to base64 for embedding in HTML
        var ImgDataURI = "data:image/png;base64," + Convert.ToBase64String(pngBinaryData);

        // Embed the image as a base64 data URI in an HTML <img> tag
        var ImgHtml = $"<img src='{ImgDataURI}'>";

        // Render the HTML as a PDF document
        using var pdfdoc = renderer.RenderHtmlAsPdf(ImgHtml);

        // Save the rendered PDF document
        pdfdoc.SaveAs("embedded_example_1.pdf");
    }
}

Imports IronPdf
Imports System.IO
Imports System.Drawing

Friend Class PDFImageAdder
	' This method demonstrates how to convert an image file to a PDF document in C# 
	Shared Sub Main(ByVal args() As String)
		' Initialize IronPdf Renderer
		Dim renderer = New IronPdf.ChromePdfRenderer()

		' Read the PNG image file into binary format
		Dim pngBinaryData = File.ReadAllBytes("embed_me.png")

		' Convert image binary data to base64 for embedding in HTML
		Dim ImgDataURI = "data:image/png;base64," & Convert.ToBase64String(pngBinaryData)

		' Embed the image as a base64 data URI in an HTML <img> tag
		Dim ImgHtml = $"<img src='{ImgDataURI}'>"

		' Render the HTML as a PDF document
		Dim pdfdoc = renderer.RenderHtmlAsPdf(ImgHtml)

		' Save the rendered PDF document
		pdfdoc.SaveAs("embedded_example_1.pdf")
	End Sub
End Class

This program will load the image first. The ReadAllBytes function converts the image into bytes format in the above code. After that, the image data will be encoded into base64 and placed into an HTML <img> tag as a string. After that, the HTML string will be rendered to a PDF by using the RenderHtmlAsPdf method function. It will create a PDF page in the PDF document.

The next example will show how to use a Bitmap image in the PDF document. IronPDF has a useful method to embed a System.Drawing.Image in an HTML document, which may then be rendered as a PDF. Visit the following ImageUtilities API to understand more about it. The following code will show how it works:

using IronPdf;
using System.Drawing;

class PDFImageAdder
{
    static void Main(string[] args)
    {
        // Initialize IronPdf Renderer
        var renderer = new IronPdf.ChromePdfRenderer();

        // Create a Bitmap image
        Bitmap MyImage = new Bitmap("Path-to-Your-Image");

        // Convert the Bitmap image to a Data URI
        string DataURI = IronPdf.Util.ImageToDataUri(MyImage);

        // Embed the image as a Data URI in an HTML <img> tag
        var ImgHtml = $"<img src='{DataURI}'>";

        // Render the HTML to PDF
        using var pdfdoc2 = renderer.RenderHtmlAsPdf(ImgHtml);

        // Save the PDF document
        pdfdoc2.SaveAs("embedded_example_2.pdf");
    }
}

using IronPdf;
using System.Drawing;

class PDFImageAdder
{
    static void Main(string[] args)
    {
        // Initialize IronPdf Renderer
        var renderer = new IronPdf.ChromePdfRenderer();

        // Create a Bitmap image
        Bitmap MyImage = new Bitmap("Path-to-Your-Image");

        // Convert the Bitmap image to a Data URI
        string DataURI = IronPdf.Util.ImageToDataUri(MyImage);

        // Embed the image as a Data URI in an HTML <img> tag
        var ImgHtml = $"<img src='{DataURI}'>";

        // Render the HTML to PDF
        using var pdfdoc2 = renderer.RenderHtmlAsPdf(ImgHtml);

        // Save the PDF document
        pdfdoc2.SaveAs("embedded_example_2.pdf");
    }
}

Imports IronPdf
Imports System.Drawing

Friend Class PDFImageAdder
	Shared Sub Main(ByVal args() As String)
		' Initialize IronPdf Renderer
		Dim renderer = New IronPdf.ChromePdfRenderer()

		' Create a Bitmap image
		Dim MyImage As New Bitmap("Path-to-Your-Image")

		' Convert the Bitmap image to a Data URI
		Dim DataURI As String = IronPdf.Util.ImageToDataUri(MyImage)

		' Embed the image as a Data URI in an HTML <img> tag
		Dim ImgHtml = $"<img src='{DataURI}'>"

		' Render the HTML to PDF
		Dim pdfdoc2 = renderer.RenderHtmlAsPdf(ImgHtml)

		' Save the PDF document
		pdfdoc2.SaveAs("embedded_example_2.pdf")
	End Sub
End Class

In the above code, the ImageToDataUri function is used to convert an image into a URI format. The image is then drawn in the PDF document using the RenderHtmlAsPdf function. This applies to multiple images.

Additionally, IronPDF is also capable of rendering charts in PDFs, adding barcodes to PDF documents, enhancing PDF security with passwords and watermarking PDF files, and even handling PDF forms programmatically.