Coordinate system in PDF with C# and .NET

Creating PDF documents using C# and .NET requires an understanding of the coordinate system that is used to accurately place elements on the page. In this article, we will look at the basics of the coordinate system in PDF. PDF documents use a Cartesian coordinate system, where the point (0, 0) is in the lower left corner of the page. The coordinates increase to the right and up. This differs from many other systems where the origin is in the upper left corner.

Understanding the coordinate system in PDF documents and the ability to use it in C# and .NET allows you to create professionally designed documents with precise placement of elements. SautinSoft library PDF .Net provides powerful tools for working with PDF, making the process of creating and manipulating documents simple and efficient.

    Step-by-step guide:

  1. Add SautinSoft.PDF from NuGet.
  2. Create a new PDF document and add a new page.
  3. Draw lines on all sides of the page.
  4. Draw the text at the corners of the page.
  5. Save the document.

Complete code

using System;
using System.Drawing;
using System.IO;
using System.Reflection;
using System.Security.Cryptography.X509Certificates;
using SautinSoft;
using SautinSoft.Pdf;
using SautinSoft.Pdf.Content;

namespace Sample
{
    class Sample
    {
        /// <summary>
        /// Coordinate system in PDF document using C# and .NET
        /// </summary>
        /// <remarks>
        /// Details: https://sautinsoft.com/products/pdf/help/net/developer-guide/coordinate-system-in-pdf-document-using-csharp-and-dotnet.php
        /// </remarks>
        static void Main(string[] args)
        {
            // Before starting this example, please get a free 100-day trial key:
            // https://sautinsoft.com/start-for-free/

            // Apply the key here:
            // PdfDocument.SetLicense("...");

            using (var document = new PdfDocument())
            {
                // Add a page.
                var page = document.Pages.Add();

                // NOTE: In PDF, location (0, 0) is at the bottom-left corner of the page
                // and the positive y axis extends vertically upward.
                var pageBounds = page.CropBox;

                // Add a thick red line at the top of the page.
                var line1 = page.Content.Elements.AddPath();
                line1.BeginSubpath(new PdfPoint(596, pageBounds.Top - 0)).
                    LineTo(new PdfPoint(pageBounds.Left - 0, pageBounds.Top - 0));
                var line1Format = line1.Format;
                line1Format.Stroke.IsApplied = true;
                line1Format.Stroke.Width = 5;
                line1Format.Stroke.Color = PdfColor.FromRgb(1, 0, 0);
                // Add a thick blue line to the left of the page.
                var line2 = page.Content.Elements.AddPath();
                line2.BeginSubpath(new PdfPoint(596, pageBounds.Left - 0)).
                    LineTo(new PdfPoint(pageBounds.Right - 0, pageBounds.Top - 0));
                var line2Format = line2.Format;
                line2Format.Stroke.IsApplied = true;
                line2Format.Stroke.Width = 5;
                line2Format.Stroke.Color = PdfColor.FromRgb(0, 0, 1);
                // Add a thick red line at the bottom of the page.
                var line3 = page.Content.Elements.AddPath();
                line3.BeginSubpath(new PdfPoint(596, pageBounds.Left - 0)).
                    LineTo(new PdfPoint(pageBounds.Left - 0, pageBounds.Bottom - 0));
                var line3Format = line3.Format;
                line3Format.Stroke.IsApplied = true;
                line3Format.Stroke.Width = 5;
                line3Format.Stroke.Color = PdfColor.FromRgb(1, 0, 0);
                // Add a thick red line to the right of the page.
                var line4 = page.Content.Elements.AddPath();
                line4.BeginSubpath(new PdfPoint(0, pageBounds.Right - 596)).
                    LineTo(new PdfPoint(pageBounds.Right - 596, pageBounds.Top - 0));
                var line4Format = line4.Format;
                line4Format.Stroke.IsApplied = true;
                line4Format.Stroke.Width = 5;
                line4Format.Stroke.Color = PdfColor.FromRgb(0, 0, 1);

                double margin = 15;
                using (var formattedText = new PdfFormattedText())
                {
                    // Set up and fill the PdfFormattedText object.
                    formattedText.TextAlignment = PdfTextAlignment.Left;
                    formattedText.MaxTextWidth = 100;
                    formattedText.Color = PdfColor.FromRgb(0, 0, 0);
                    formattedText.Append("(");
                    formattedText.Color = PdfColor.FromRgb(1, 0, 0);
                    formattedText.Append("0");
                    formattedText.Color = PdfColor.FromRgb(0, 0, 0);
                    formattedText.Append(";");
                    formattedText.Color = PdfColor.FromRgb(0, 0, 1);
                    formattedText.Append("842");
                    formattedText.Color = PdfColor.FromRgb(0, 0, 0);
                    formattedText.Append(")");
                    // Draw text in the top-left corner of the page.
                    page.Content.DrawText(formattedText,
                        new PdfPoint(margin,
                        page.CropBox.Top - margin - formattedText.Height));

                    // Clear the PdfFormattedText object.
                    formattedText.Clear();

                    // Set up and fill the PdfFormattedText object.
                    formattedText.TextAlignment = PdfTextAlignment.Right;
                    formattedText.MaxTextWidth = 100;
                    formattedText.Color = PdfColor.FromRgb(0, 0, 0);
                    formattedText.Append("(");
                    formattedText.Color = PdfColor.FromRgb(1, 0, 0);
                    formattedText.Append("596");
                    formattedText.Color = PdfColor.FromRgb(0, 0, 0);
                    formattedText.Append(";");
                    formattedText.Color = PdfColor.FromRgb(0, 0, 1);
                    formattedText.Append("842");
                    formattedText.Color = PdfColor.FromRgb(0, 0, 0);
                    formattedText.Append(")");
                    // Draw text in the top-right corner of the page.
                    page.Content.DrawText(formattedText,
                        new PdfPoint(page.CropBox.Width - margin - formattedText.MaxTextWidth,
                    page.CropBox.Top - margin - formattedText.Height));

                    // Clear the PdfFormattedText object.
                    formattedText.Clear();

                    // Set up and fill the PdfFormattedText object.
                    formattedText.TextAlignment = PdfTextAlignment.Right;
                    formattedText.MaxTextWidth = 100;
                    formattedText.Color = PdfColor.FromRgb(0, 0, 0);
                    formattedText.Append("(");
                    formattedText.Color = PdfColor.FromRgb(1, 0, 0);
                    formattedText.Append("596");
                    formattedText.Color = PdfColor.FromRgb(0, 0, 0);
                    formattedText.Append(";");
                    formattedText.Color = PdfColor.FromRgb(0, 0, 1);
                    formattedText.Append("0");
                    formattedText.Color = PdfColor.FromRgb(0, 0, 0);
                    formattedText.Append(")");
                    // Draw text in the bottom-right corner of the page.
                    page.Content.DrawText(formattedText,
                        new PdfPoint(page.CropBox.Width - margin - formattedText.MaxTextWidth,
                    margin));

                    // Clear the PdfFormattedText object.
                    formattedText.Clear();

                    // Set up and fill the PdfFormattedText object.
                    formattedText.TextAlignment = PdfTextAlignment.Left;
                    formattedText.MaxTextWidth = 100;
                    formattedText.Color = PdfColor.FromRgb(0, 0, 0);
                    formattedText.Append("(");
                    formattedText.Color = PdfColor.FromRgb(1, 0, 0);
                    formattedText.Append("0");
                    formattedText.Color = PdfColor.FromRgb(0, 0, 0);
                    formattedText.Append(";");
                    formattedText.Color = PdfColor.FromRgb(0, 0, 1);
                    formattedText.Append("0");
                    formattedText.Color = PdfColor.FromRgb(0, 0, 0);
                    formattedText.Append(")");
                    // Draw text in the bottom-left corner of the page.
                    page.Content.DrawText(formattedText,
                        new PdfPoint(margin,
                    margin));

                    // Save a PDF Document.
                    document.Save("Coordinate system.pdf");
                }
            }
            System.Diagnostics.Process.Start(new System.Diagnostics.ProcessStartInfo("Coordinate system.pdf") { UseShellExecute = true });
        }
    }

}

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Option Infer On
Imports System
Imports System.Drawing
Imports System.IO
Imports System.Reflection.Metadata
Imports System.Security.Cryptography.X509Certificates
Imports SautinSoft
Imports SautinSoft.Pdf
Imports SautinSoft.Pdf.Content

Namespace Sample
    Class Sample
        Shared Sub Main(ByVal args As String())
            Using document = New PdfDocument()
                Dim page = document.Pages.Add()
                Dim pageBounds = page.CropBox
                Dim line1 = page.Content.Elements.AddPath()
                line1.BeginSubpath(New PdfPoint(596, pageBounds.Top - 0)).LineTo(New PdfPoint(pageBounds.Left - 0, pageBounds.Top - 0))
                Dim line1Format = line1.Format
                line1Format.Stroke.IsApplied = True
                line1Format.Stroke.Width = 5
                line1Format.Stroke.Color = PdfColor.FromRgb(1, 0, 0)
                Dim line2 = page.Content.Elements.AddPath()
                line2.BeginSubpath(New PdfPoint(596, pageBounds.Left - 0)).LineTo(New PdfPoint(pageBounds.Right - 0, pageBounds.Top - 0))
                Dim line2Format = line2.Format
                line2Format.Stroke.IsApplied = True
                line2Format.Stroke.Width = 5
                line2Format.Stroke.Color = PdfColor.FromRgb(0, 0, 1)
                Dim line3 = page.Content.Elements.AddPath()
                line3.BeginSubpath(New PdfPoint(596, pageBounds.Left - 0)).LineTo(New PdfPoint(pageBounds.Left - 0, pageBounds.Bottom - 0))
                Dim line3Format = line3.Format
                line3Format.Stroke.IsApplied = True
                line3Format.Stroke.Width = 5
                line3Format.Stroke.Color = PdfColor.FromRgb(1, 0, 0)
                Dim line4 = page.Content.Elements.AddPath()
                line4.BeginSubpath(New PdfPoint(0, pageBounds.Right - 596)).LineTo(New PdfPoint(pageBounds.Right - 596, pageBounds.Top - 0))
                Dim line4Format = line4.Format
                line4Format.Stroke.IsApplied = True
                line4Format.Stroke.Width = 5
                line4Format.Stroke.Color = PdfColor.FromRgb(0, 0, 1)
                Dim margin As Double = 15

                Using formattedText = New PdfFormattedText()
                    formattedText.TextAlignment = PdfTextAlignment.Left
                    formattedText.MaxTextWidth = 100
                    formattedText.Color = PdfColor.FromRgb(0, 0, 0)
                    formattedText.Append("(")
                    formattedText.Color = PdfColor.FromRgb(1, 0, 0)
                    formattedText.Append("0")
                    formattedText.Color = PdfColor.FromRgb(0, 0, 0)
                    formattedText.Append(";")
                    formattedText.Color = PdfColor.FromRgb(0, 0, 1)
                    formattedText.Append("842")
                    formattedText.Color = PdfColor.FromRgb(0, 0, 0)
                    formattedText.Append(")")
                    page.Content.DrawText(formattedText, New PdfPoint(margin, page.CropBox.Top - margin - formattedText.Height))
                    formattedText.Clear()
                    formattedText.TextAlignment = PdfTextAlignment.Right
                    formattedText.MaxTextWidth = 100
                    formattedText.Color = PdfColor.FromRgb(0, 0, 0)
                    formattedText.Append("(")
                    formattedText.Color = PdfColor.FromRgb(1, 0, 0)
                    formattedText.Append("596")
                    formattedText.Color = PdfColor.FromRgb(0, 0, 0)
                    formattedText.Append(";")
                    formattedText.Color = PdfColor.FromRgb(0, 0, 1)
                    formattedText.Append("842")
                    formattedText.Color = PdfColor.FromRgb(0, 0, 0)
                    formattedText.Append(")")
                    page.Content.DrawText(formattedText, New PdfPoint(page.CropBox.Width - margin - formattedText.MaxTextWidth, page.CropBox.Top - margin - formattedText.Height))
                    formattedText.Clear()
                    formattedText.TextAlignment = PdfTextAlignment.Right
                    formattedText.MaxTextWidth = 100
                    formattedText.Color = PdfColor.FromRgb(0, 0, 0)
                    formattedText.Append("(")
                    formattedText.Color = PdfColor.FromRgb(1, 0, 0)
                    formattedText.Append("596")
                    formattedText.Color = PdfColor.FromRgb(0, 0, 0)
                    formattedText.Append(";")
                    formattedText.Color = PdfColor.FromRgb(0, 0, 1)
                    formattedText.Append("0")
                    formattedText.Color = PdfColor.FromRgb(0, 0, 0)
                    formattedText.Append(")")
                    page.Content.DrawText(formattedText, New PdfPoint(page.CropBox.Width - margin - formattedText.MaxTextWidth, margin))
                    formattedText.Clear()
                    formattedText.TextAlignment = PdfTextAlignment.Left
                    formattedText.MaxTextWidth = 100
                    formattedText.Color = PdfColor.FromRgb(0, 0, 0)
                    formattedText.Append("(")
                    formattedText.Color = PdfColor.FromRgb(1, 0, 0)
                    formattedText.Append("0")
                    formattedText.Color = PdfColor.FromRgb(0, 0, 0)
                    formattedText.Append(";")
                    formattedText.Color = PdfColor.FromRgb(0, 0, 1)
                    formattedText.Append("0")
                    formattedText.Color = PdfColor.FromRgb(0, 0, 0)
                    formattedText.Append(")")
                    page.Content.DrawText(formattedText, New PdfPoint(margin, margin))
                    document.Save("Coordinate system.pdf")
                End Using
            End Using

            System.Diagnostics.Process.Start(New System.Diagnostics.ProcessStartInfo("Coordinate system.pdf") With {
                .UseShellExecute = True
            })
        End Sub
    End Class
End Namespace

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