Get PDF page size in C#

With Spire.PDF for .NET, developers can set page size for PDF in C#. This article will demonstrates how to get the PDF page size using Spire.PDF.

Detail steps:

Step 1: Create a PdfDocument instance and load the sample.pdf file.

PdfDocument doc = new PdfDocument();
doc.LoadFromFile("Sample.pdf");

Step 2: Get the width and height of the first page in the PDF file.

PdfPageBase page = doc.Pages[0];
float pointWidth = page.Size.Width;
float pointHeight = page.Size.Height;

Step 3: Convert the size with other measurement unit, such as in Inch, Centimeter, Unit or Pixel.

//Create PdfUnitConvertor to convert the unit
PdfUnitConvertor unitCvtr = new PdfUnitConvertor();

//Convert the size with "pixel"
float pixelWidth = unitCvtr.ConvertUnits(pointWidth, PdfGraphicsUnit.Point, PdfGraphicsUnit.Pixel);
float pixelHeight = unitCvtr.ConvertUnits(pointHeight, PdfGraphicsUnit.Point, PdfGraphicsUnit.Pixel);

//Convert the size with "inch"
float inchWidth = unitCvtr.ConvertUnits(pointWidth, PdfGraphicsUnit.Point, PdfGraphicsUnit.Inch);
float inchHeight = unitCvtr.ConvertUnits(pointHeight, PdfGraphicsUnit.Point, PdfGraphicsUnit.Inch);

//Convert the size with "centimeter"
float centimeterWidth = unitCvtr.ConvertUnits(pointWidth, PdfGraphicsUnit.Point, PdfGraphicsUnit.Centimeter);
float centimeterHeight = unitCvtr.ConvertUnits(pointHeight, PdfGraphicsUnit.Point, PdfGraphicsUnit.Centimeter);

Step 4: Save to a .txt file.

//Create StringBuilder to save 
StringBuilder content = new StringBuilder();
//Add pointSize string to StringBuilder
content.AppendLine("The page size of the file is (width: " + pointWidth + "pt, height: " + pointHeight + "pt).");
content.AppendLine("The page size of the file is (width: " + pixelWidth + "pixel, height: " + pixelHeight + "pixel).");
content.AppendLine("The page size of the file is (width: " + inchWidth + "inch, height: " + inchHeight + "inch).");
content.AppendLine("The page size of the file is (width: " + centimeterWidth + "cm, height: " + centimeterHeight + "cm.)");

String output = "GetPageSize_out.txt";
//Save them to a txt file
File.WriteAllText(output, content.ToString());

Output:

Get PDF page size in C#

Full code:

using Spire.Pdf;
using Spire.Pdf.Actions;
using Spire.Pdf.General;
using Spire.Pdf.Graphics;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace GetPDFPageSize
{
    class Program
    {
        static void Main(string[] args)
        {

            PdfDocument doc = new PdfDocument();
            doc.LoadFromFile("Sample.pdf");

            //Get the first page of the loaded PDF file
            PdfPageBase page = doc.Pages[0];
            //Get the width of page based on "point"
            float pointWidth = page.Size.Width;
            //Get the height of page
            float pointHeight = page.Size.Height;

            //Create PdfUnitConvertor to convert the unit
            PdfUnitConvertor unitCvtr = new PdfUnitConvertor();

            //Convert the size with "pixel"
            float pixelWidth = unitCvtr.ConvertUnits(pointWidth, PdfGraphicsUnit.Point, PdfGraphicsUnit.Pixel);
            float pixelHeight = unitCvtr.ConvertUnits(pointHeight, PdfGraphicsUnit.Point, PdfGraphicsUnit.Pixel);

            //Convert the size with "inch"
            float inchWidth = unitCvtr.ConvertUnits(pointWidth, PdfGraphicsUnit.Point, PdfGraphicsUnit.Inch);
            float inchHeight = unitCvtr.ConvertUnits(pointHeight, PdfGraphicsUnit.Point, PdfGraphicsUnit.Inch);

            //Convert the size with "centimeter"
            float centimeterWidth = unitCvtr.ConvertUnits(pointWidth, PdfGraphicsUnit.Point, PdfGraphicsUnit.Centimeter);
            float centimeterHeight = unitCvtr.ConvertUnits(pointHeight, PdfGraphicsUnit.Point, PdfGraphicsUnit.Centimeter);

            //Create StringBuilder to save 
            StringBuilder content = new StringBuilder();
            
            //Add pointSize string to StringBuilder
            content.AppendLine("The page size of the file is (width: " + pointWidth + "pt, height: " + pointHeight + "pt).");
            content.AppendLine("The page size of the file is (width: " + pixelWidth + "pixel, height: " + pixelHeight + "pixel).");
            content.AppendLine("The page size of the file is (width: " + inchWidth + "inch, height: " + inchHeight + "inch).");
            content.AppendLine("The page size of the file is (width: " + centimeterWidth + "cm, height: " + centimeterHeight + "cm.)");

            String output = "GetPageSize_out.txt";

            //Save them to a txt file
            File.WriteAllText(output, content.ToString());        

        }
    }
}

Get PDF page size in C#

See Also