Compress and optimize PDF files in C# and VB.NET

using System;
using System.IO;
using SautinSoft.Pdf;

class Program
{
	static void Main()
	{
		// This property is necessary only for licensed version.
		//SautinSoft.Pdf.Serial = "XXXXXXXXXXX";

		string input_path = "../../TestFiles/";
		string output_path = "../../TestFiles/Output/";
		string input_filename = "newsletter";

		try
		{
			using (PdfDocument doc = new PdfDocument(input_path + input_filename + ".pdf"))
			{
				Optimizer.Optimize(doc);
				doc.Save(output_path + input_filename + "_opt1.pdf", SaveOptions.e_linearized);
			}
		}
	}
}

using System;
using System.IO;
using SautinSoft.Pdf;

class Program
{
	static void Main()
	{
		// This property is necessary only for licensed version.
		//SautinSoft.Pdf.Serial = "XXXXXXXXXXX";

		string input_path = "../../TestFiles/";
		string output_path = "../../TestFiles/Output/";
		string input_filename = "newsletter";
		try
		{
			using (PdfDocument doc = new PdfDocument(input_path + input_filename + ".pdf"))
			{
				Optimizer.ImageSettings image_settings = new Optimizer.ImageSettings();
				// low quality jpeg compression
				image_settings.SetCompressionMode(Optimizer.ImageSettings.CompressionMode.e_jpeg);
				image_settings.SetQuality(1);

				// Set the output dpi to be standard screen resolution
				image_settings.SetImageDPI(144,96);

				// this option will recompress images not compressed with
				// jpeg compression and use the result if the new image
				// is smaller.
				image_settings.ForceRecompression(true);

				// this option is not commonly used since it can
				// potentially lead to larger files. It should be enabled
				// only if the output compression specified should be applied
				// to every image of a given type regardless of the output image size
				//image_settings.ForceChanges(true);
				// use the same settings for both color and grayscale images
				Optimizer.OptimizerSettings opt_settings = new Optimizer.OptimizerSettings();
				opt_settings.SetColorImageSettings(image_settings);
				opt_settings.SetGrayscaleImageSettings(image_settings);

				Optimizer.Optimize(doc, opt_settings);
				doc.Save(output_path + input_filename + "_opt2.pdf", SaveOptions.e_linearized);
			}
		}
	}
}

using System;
using System.IO;
using SautinSoft.Pdf;

class Program
{
	static void Main()
	{
		// This property is necessary only for licensed version.
		//SautinSoft.Pdf.Serial = "XXXXXXXXXXX";

		string input_path = "../../TestFiles/";
		string output_path = "../../TestFiles/Output/";
		string input_filename = "newsletter";

		try
		{
			using (PdfDocument doc = new PdfDocument(input_path + input_filename + ".pdf"))
			{
				Optimizer.MonoImageSettings mono_image_settings = new Optimizer.MonoImageSettings();
				mono_image_settings.SetCompressionMode(Optimizer.MonoImageSettings.CompressionMode.e_jbig2);
				mono_image_settings.ForceRecompression(true);

				Optimizer.OptimizerSettings opt_settings = new Optimizer.OptimizerSettings();
				opt_settings.SetMonoImageSettings(mono_image_settings);

				Optimizer.Optimize(doc, opt_settings);

				doc.Save(output_path + input_filename + "_opt3.pdf", SaveOptions.e_linearized);
			}
		}
	}
}

using System;
using System.IO;
using SautinSoft.Pdf;

class Program
{
	static void Main()
	{
		// This property is necessary only for licensed version.
		//SautinSoft.Pdf.Serial = "XXXXXXXXXXX";

		string input_path = "../../TestFiles/";
		string output_path = "../../TestFiles/Output/";
		string input_filename = "newsletter";

		try
		{
			using (PdfDocument doc = new PdfDocument(input_path + "TigerText.pdf"))
			{
				doc.InitSecurityHandler();

				Flattener fl = new Flattener();
				// The following lines can increase the resolution of background
				// images.
				//fl.SetDPI(300);
				//fl.SetMaximumImagePixels(5000000);
				// This line can be used to output Flate compressed background
				// images rather than DCTDecode compressed images which is the default
				//fl.SetPreferJPG(false);
				// In order to adjust thresholds for when text is Flattened
				// the following function can be used.
				//fl.SetThreshold(Flattener.Threshold.e_keep_most);
				// We use e_fast option here since it is usually preferable
				// to avoid Flattening simple pages in terms of size and
				// rendering speed. If the desire is to simplify the
				// document for processing such that it contains only text and
				// a background image e_simple should be used instead.

				fl.Process(doc,Flattener.FlattenMode.e_fast);

				doc.Save(output_path + "TigerText_flatten.pdf", SaveOptions.e_linearized);
			}
		}
	}
}

using System;
using System.IO;
using SautinSoft.Pdf;

class Program
{
	static void Main()
	{
		// This property is necessary only for licensed version.
		//SautinSoft.Pdf.Serial = "XXXXXXXXXXX";
		string input_path = "../../TestFiles/";
		string output_path = "../../TestFiles/Output/";
		string input_filename = "newsletter";

		try
		{
			using (PdfDocument doc = new PdfDocument(input_path + input_filename + ".pdf"))
			{
				doc.InitSecurityHandler();

				ViewerOptimizedOptions opts = new ViewerOptimizedOptions();
				// set the maximum dimension (width or height) that thumbnails will have.
				opts.SetThumbnailSize(1500);
				// set thumbnail rendering threshold. A number from 0 (include all thumbnails) to 100 (include only the first thumbnail)
				// representing the complexity at which SaveViewerOptimized would include the thumbnail.
				// By default it only produces thumbnails on the first and complex pages.
				// The following line will produce thumbnails on every page.
				// opts.SetThumbnailRenderingThreshold(0);

				doc.SaveViewerOptimized(output_path + input_filename + "_SaveViewerOptimized.pdf", opts);
			}
		}
	}
}