How to add text and images to PDF in C# with PDF.co Web API

Tutorial on how to add text and images to PDF in C#

On this page you will learn from code samples for programming in C#.Writing of the code to add text and images to PDF in C# can be done by developers of any level using PDF.co Web API. PDF.co Web API is the Rest API that provides set of data extraction functions, tools for documents manipulation, splitting and merging of pdf files. Includes built-in OCR, images recognition, can generate and read barcodes from images, scans and pdf and you can use it to add text and images to PDF with C#.

Fast application programming interfaces of PDF.co Web API for C# plus the instruction and the code below will help you quickly learn how to add text and images to PDF. In your C# project or application you may simply copy & paste the code and then run your app! Detailed tutorials and documentation are available along with installed PDF.co Web API if you’d like to dive deeper into the topic and the details of the API.

You can download free trial version of PDF.co Web API from our website to see and try many others source code samples for C#.

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AddTextToExistingPDF.csproj

      
<?xml version="1.0" encoding="utf-8"?> <Project ToolsVersion="12.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003"> <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" /> <PropertyGroup> <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration> <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform> <ProjectGuid>{1E1C2C34-017E-4605-AE2B-55EA3313BE51}</ProjectGuid> <OutputType>Exe</OutputType> <RootNamespace>AddTextToExistingPDF</RootNamespace> <AssemblyName>AddTextToExistingPDF</AssemblyName> <TargetFrameworkVersion>v4.0</TargetFrameworkVersion> <FileAlignment>512</FileAlignment> </PropertyGroup> <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' "> <PlatformTarget>AnyCPU</PlatformTarget> <DebugSymbols>true</DebugSymbols> <DebugType>full</DebugType> <Optimize>false</Optimize> <OutputPath>bin\Debug\</OutputPath> <DefineConstants>DEBUG;TRACE</DefineConstants> <ErrorReport>prompt</ErrorReport> <WarningLevel>4</WarningLevel> </PropertyGroup> <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' "> <PlatformTarget>AnyCPU</PlatformTarget> <DebugType>pdbonly</DebugType> <Optimize>true</Optimize> <OutputPath>bin\Release\</OutputPath> <DefineConstants>TRACE</DefineConstants> <ErrorReport>prompt</ErrorReport> <WarningLevel>4</WarningLevel> </PropertyGroup> <ItemGroup> <Reference Include="Newtonsoft.Json, Version=10.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed, processorArchitecture=MSIL"> <HintPath>packages\Newtonsoft.Json.10.0.3\lib\net40\Newtonsoft.Json.dll</HintPath> <Private>True</Private> </Reference> <Reference Include="System" /> <Reference Include="System.Core" /> <Reference Include="System.Xml.Linq" /> <Reference Include="System.Data" /> <Reference Include="System.Xml" /> </ItemGroup> <ItemGroup> <Compile Include="Program.cs" /> </ItemGroup> <ItemGroup> <None Include="packages.config" /> </ItemGroup> <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" /> <!-- To modify your build process, add your task inside one of the targets below and uncomment it. Other similar extension points exist, see Microsoft.Common.targets. <Target Name="BeforeBuild"> </Target> <Target Name="AfterBuild"> </Target> --> </Project>

AddTextToExistingPDF.sln

      
Microsoft Visual Studio Solution File, Format Version 12.00 # Visual Studio 15 VisualStudioVersion = 15.0.26730.10 MinimumVisualStudioVersion = 10.0.40219.1 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "AddTextToExistingPDF", "AddTextToExistingPDF.csproj", "{1E1C2C34-017E-4605-AE2B-55EA3313BE51}" EndProject Global GlobalSection(SolutionConfigurationPlatforms) = preSolution Debug|Any CPU = Debug|Any CPU Release|Any CPU = Release|Any CPU EndGlobalSection GlobalSection(ProjectConfigurationPlatforms) = postSolution {1E1C2C34-017E-4605-AE2B-55EA3313BE51}.Debug|Any CPU.ActiveCfg = Debug|Any CPU {1E1C2C34-017E-4605-AE2B-55EA3313BE51}.Debug|Any CPU.Build.0 = Debug|Any CPU {1E1C2C34-017E-4605-AE2B-55EA3313BE51}.Release|Any CPU.ActiveCfg = Release|Any CPU {1E1C2C34-017E-4605-AE2B-55EA3313BE51}.Release|Any CPU.Build.0 = Release|Any CPU EndGlobalSection GlobalSection(SolutionProperties) = preSolution HideSolutionNode = FALSE EndGlobalSection GlobalSection(ExtensibilityGlobals) = postSolution SolutionGuid = {238BD6FC-F70A-4B5C-B639-34E5B171A981} EndGlobalSection EndGlobal

Program.cs

      
using System; using System.Collections.Generic; using System.Globalization; using System.IO; using System.Net; using Newtonsoft.Json; using Newtonsoft.Json.Linq; namespace ByteScoutWebApiExample { class Program { // The authentication key (API Key). // Get your own by registering at https://app.pdf.co/documentation/api const String API_KEY = "*****************************************"; // Direct URL of source PDF file. const string SourceFileUrl = "https://bytescout-com.s3.amazonaws.com/files/demo-files/cloud-api/pdf-edit/sample.pdf"; // Comma-separated list of page indices (or ranges) to process. Leave empty for all pages. Example: '0,2-5,7-'. const string Pages = ""; // PDF document password. Leave empty for unprotected documents. const string Password = ""; // Destination PDF file name const string DestinationFile = @".\result.pdf"; // Text annotation params const string Type = "annotation"; const int X = 400; const int Y = 600; const string Text = "APPROVED"; const string FontName = "Times New Roman"; const float FontSize = 24; const string FontColor = "FF0000"; static void Main(string[] args) { // Create standard .NET web client instance WebClient webClient = new WebClient(); // Set API Key webClient.Headers.Add("x-api-key", API_KEY); // * Add text annotation * // Prepare requests params as JSON // See documentation: https://apidocs.pdf.co/?#pdf-add-text-and-images-to-pdf Dictionary<string, string> parameters = new Dictionary<string, string>(); parameters.Add("name", Path.GetFileName(DestinationFile)); parameters.Add("password", Password); parameters.Add("pages", Pages); parameters.Add("url", SourceFileUrl); parameters.Add("type", Type); parameters.Add("x", X.ToString()); parameters.Add("y", Y.ToString()); parameters.Add("text", Text); parameters.Add("fontname", FontName); parameters.Add("size", FontSize.ToString(CultureInfo.InvariantCulture)); parameters.Add("color", FontColor); // Convert dictionary of params to JSON string jsonPayload = JsonConvert.SerializeObject(parameters); try { // URL of "PDF Edit" endpoint string url = "https://api.pdf.co/v1/pdf/edit/add"; // Execute POST request with JSON payload string response = webClient.UploadString(url, jsonPayload); // Parse JSON response JObject json = JObject.Parse(response); if (json["error"].ToObject<bool>() == false) { // Get URL of generated PDF file string resultFileUrl = json["url"].ToString(); // Download generated PDF file webClient.DownloadFile(resultFileUrl, DestinationFile); Console.WriteLine("Generated PDF file saved as \"{0}\" file.", DestinationFile); } else { Console.WriteLine(json["message"].ToString()); } } catch (WebException e) { Console.WriteLine(e.ToString()); } finally { webClient.Dispose(); } Console.WriteLine(); Console.WriteLine("Press any key..."); Console.ReadKey(); } } }

packages.config

      
<?xml version="1.0" encoding="utf-8"?> <packages> <package id="Newtonsoft.Json" version="10.0.3" targetFramework="net40" /> </packages>

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