Images (JPG, PNG, BMP, etc.) are common for data capture, but PDFs provide better security, compression, and cross-platform consistency. In .NET development, developers may often need a reliable C# image to PDF solution to streamline workflows like report generation, document archiving, and digital record management.
This guide demonstrates how to efficiently convert images to PDF in C#/ ASP.NET using Spire.PDF for .NET, a powerful library that simplifies this process with robust features and excellent compatibility.
- Set Up Your Project
- How to Convert Image to PDF in C#
- Image to PDF Customization Options
- FAQs (TIFF to PDF, SVG to PDF)
- Conclusion
Set Up Your Project
Before we start writing code to convert images such as PNG to PDF, we need to set up our C# project and add the Spire.PDF library.
Step 1: Create a New C# Project
Open Visual Studio and create a new C# project. You can choose a Console Application, Windows Forms Application, or any other project type depending on your needs.
Step 2: Install Spire.PDF
There are a few ways to add the PDF converter library to your project. One common method is through NuGet Package Manager.
- In Visual Studio, right-click on your project in the Solution Explorer, select "Manage NuGet Packages".
- In the NuGet Package Manager window, search for "Spire.PDF".
- Then, click "Install" to add the latest version of the library to your project.
Once the installation is complete, you'll be able to reference the necessary namespaces in your C# code.
How to Convert Image to PDF in C#
Spire.PDF does not provide a straightforward method to convert images to PDF. But you could create a new PDF document and draw images at the specified locations of a certain page. The following are two code examples for single/multiple image conversion.
Converting a Single Image to PDF
This example shows how to convert a JPG image to a PDF document, with the PDF page match the exact dimensions of the image.
C# code for JPG to PDF conversion:
using System.Drawing;
using Spire.Pdf;
using Spire.Pdf.Graphics;
namespace ConvertImageToPdf
{
class Program
{
static void Main(string[] args)
{
// Create a PdfDocument object
PdfDocument doc = new PdfDocument();
// Set the margins to 0
doc.PageSettings.SetMargins(0);
// Load an image
Image image = Image.FromFile(@"C:\Users\Administrator\Desktop\announcement.jpg");
// Get the image width and height
float width = image.PhysicalDimension.Width;
float height = image.PhysicalDimension.Height;
// Add a page of the same size as the image
PdfPageBase page = doc.Pages.Add(new SizeF(width, height));
// Load a JPG image and draw it at (0, 0) of the page
PdfImage pdfImage = PdfImage.FromImage(image);
page.Canvas.DrawImage(pdfImage, 0, 0, pdfImage.Width, pdfImage.Height);
// Save the PDF file
doc.SaveToFile("ConvertPdfWithSameSize.pdf");
}
}
}
Explanation:
- PdfDocument: Represents the PDF file.
- PdfPageBase: A page in the PDF document.
- PdfImage.FromImage: Converts an Image object to a PDF image.
- DrawImage: Renders the image on the PDF page.
Output:
Converting Multiple Images to a Single PDF
If you have multiple images that you want to combine into a single PDF document, the process is similar to the single-image conversion, but with a loop to handle each image.
C# code to convert JPG, PNG, TIFF, BMP to PDF:
using Spire.Pdf;
using Spire.Pdf.Graphics;
using System.Drawing;
namespace ConvertMultipleImagesIntoPdf
{
class Program
{
static void Main(string[] args)
{
// Create a PdfDocument object
PdfDocument pdf = new PdfDocument();
// Set the page margins to 0
pdf.PageSettings.SetMargins(0);
// Specify the images to be converted
string[] imagePaths = {"Image-1.png", "Image-2.jpg", "Image-3.bmp", "Image-4.tiff"};
// Iterate through each image
foreach (string path in imagePaths)
{
// Load a particular image
Image image = Image.FromFile(path);
// Get the image width and height
float width = image.PhysicalDimension.Width;
float height = image.PhysicalDimension.Height;
// Add a page that has the same size as the image
PdfPageBase page = pdf.Pages.Add(new SizeF(width, height));
//Create a PdfImage object based on the image
PdfImage pdfImage = PdfImage.FromImage(image);
// Draw image at (0, 0) of the page
page.Canvas.DrawImage(pdfImage, 0, 0, pdfImage.Width, pdfImage.Height);
}
// Save the PDF file
pdf.SaveToFile("CombinaImagesToPdf.pdf");
pdf.Dispose();
}
}
}
This C# code loops through an array of image files in different formats, loads each image, adds it to a new page in the PDF document, and then saves the final PDF with all the images.
Output:
Image to PDF Customization Options
Adjust Page Settings
While conversion, you can customize PDF page properties such as orientation, margins, and size according to the nature of your images:
// Create a PDF document
PdfDocument pdf = new PdfDocument();
// Set page orientation
pdf.PageSettings.Orientation = PdfPageOrientation.Landscape;
// Set page margins (in points, 1 point = 1/72 inch)
pdf.PageSettings.SetMargins(20);
// Set page size
pdf.PageSettings.Size = PdfPageSize.A4;
Resize Images for Optimal Fit
If you need to maintain a fixed PDF page size, you can scale the image to make it fit to page:
// Set fixed page size (e.g., A4)
PdfPageBase page = pdf.Pages.Add(PdfPageSize.A4);
//Load an image
Image image = Image.FromFile("sample.jpg");
// Get the width and heigh of the page
float pageWidth = page.Canvas.ClientSize.Width;
float pageHeight = page.Canvas.ClientSize.Height;
// Scale the image
float scale = Math.Min(pageWidth / image.Width, pageHeight / image.Height);
float scaledWidth = image.Width * scale;
float scaledHeight = image.Height * scale;
// Draw the scaled image on the page
page.Canvas.DrawImage(PdfImage.FromImage(image), 0, 0, scaledWidth, scaledHeight);
FAQs (TIFF to PDF, SVG to PDF)
Q1: What image formats does Spire.PDF support?
A: Spire.PDF seamlessly supports all major image formats:
- JPG/ JPEG
- PNG
- BMP
- TIFF
- GIF
- EMF
- WMF
Ensure your input image is in a supported format for seamless conversion.
Q2: Can I convert a multi-page TIFF image to PDF?
A: Yes! Iterate through TIFF frames to convert. The full code example can be found at: Convert a Multi-Page TIFF Image to a PDF File in C#
Q3: Can I convert SVG image to PDF?
A: Yes! You can load an SVG file with LoadFromSvg() and then save it as a PDF through the SaveToFile(String, FileFormat.PDF) method.
using Spire.Pdf;
namespace SVGtoPDF
{
class Program
{
static void Main(string[] args)
{
// Create a PdfDocument object
PdfDocument doc = new PdfDocument();
// Load a sample SVG file
doc.LoadFromSvg("Sample.svg");
// Save SVG to PDF document
doc.SaveToFile("SVGtoPDF.pdf", FileFormat.PDF);
doc.Dispose();
}
}
}
Q4: Where can I find the VB.NET demos for image to PDF conversion?
A: Spire.PDF fully supports VB.NET. You can convert the C# code samples provided above to VB.NET via code converter tools (e.g. Telerik Code Converter).
Conclusion
With Spire.PDF for .NET, converting images to PDF in C# becomes simple and flexible. This guide shows you how to:
- Convert a single or multiple images into a PDF document.
- Customize page size, margins, and layout for your PDF output.
By following the examples in this guide, you can seamlessly integrate image-to-PDF conversion into your .NET applications.
For advanced features (encryption, annotation), explore Spire.PDF’s online documentation.
Get a Free License
Need to remove watermarks on output files and get rid of restrictions? You can request a 30-day full-featured trial license. A tutorial on how to use the license file is available here.
