ImgCompressorForm.cs

using System;
using System.IO;
using System.Windows.Forms;
using System.Drawing.Imaging;
using System.Drawing;
using System.Threading;
using System.Collections.Generic;
using System.Diagnostics;
using Ini;

namespace ImgCompressor
{
    public partial class Form1 : Form
    {
        static NumericUpDown numUpDown1, numUpDown2;
        static List<string> newFiles = new List<string>();
        static string imgFolder = "", iniPath;
        static int imgQuality = 0;
        static double sizeBefore, sizeAfter;
        static Stopwatch time;
        static IniFile ini;

        public Form1()
        {
            InitializeComponent();
            // static links
            numUpDown1 = numericUpDown1;
            numUpDown2 = numericUpDown2;
            iniPath = string.Format("{0}{1}", AppDomain.CurrentDomain.BaseDirectory, "settings.ini");
            ini = new IniFile(iniPath);
            imgFolder = ini.IniReadValue("Main", "imgFolder");

            if (imgFolder.Length > 0) { 
                textBox1.Text = imgFolder;
            }
        }

        private void button1_Click(object sender, EventArgs e)
        {
            folderBrowserDialog1.ShowDialog();
            imgFolder = folderBrowserDialog1.SelectedPath;
            textBox1.Text = imgFolder;

            if (imgFolder.Length > 0) {
                ini.IniWriteValue("Main", "imgFolder", imgFolder);
            }
        }

        private void button2_Click(object sender, EventArgs e)
        {
            if (imgFolder.Length > 0) {
                newFiles.Clear();
                time = Stopwatch.StartNew();
                ThreadFactory tf = new ThreadFactory();
                tf.Start();
            }
            else {
                MessageBox.Show("Please select a folder");
            }
        }

        class ThreadFactory
        {
            int count = 0;
            object locker = new object();

            public void Start()
            {
                if (!Directory.Exists(imgFolder + "\\compressed")) {
                    Directory.CreateDirectory(imgFolder + "\\compressed");
                }

                imgQuality = Convert.ToInt32(numUpDown1.Value);
                string[] files = Directory.GetFiles(imgFolder);
                sizeBefore = countFilesSize(files);

                int maxThreads = Convert.ToInt32(numUpDown2.Value);
                ThreadPool.SetMaxThreads(maxThreads, maxThreads);

                ThreadPool.QueueUserWorkItem(threadFunc, files);
            }

            void threadFunc(Object threadContext)
            {
                lock (locker)
                {
                    string[] files = (string[])threadContext;

                    string file = files[count];
                    string newPath = imgFolder + "\\compressed\\" + getFileName(imgFolder, file);
                    newFiles.Add(newPath);

                    try
                    {
                        if (!File.Exists(newPath))
                        {
                            bool compressed = CompressJpeg(newPath, Image.FromFile(file, true), 80);

                            if (!compressed) {
                                throw new Exception();
                            }
                        }
                    }
                    catch {
                        if (!File.Exists(newPath)) {
                            File.Copy(file, newPath);
                        }
                    }
                    count++;

                    if (count < files.Length) {
                        ThreadPool.QueueUserWorkItem(threadFunc, files);
                    }
                    else {
                        time.Stop();
                        sizeAfter = countFilesSize(newFiles.ToArray());
                        double diff = Math.Round((sizeBefore - sizeAfter) / 1024.0, 2);
                        MessageBox.Show("Done!\n\nYou save " + diff.ToString() + " mb\n\nElapsed time: " + time.Elapsed.TotalMilliseconds.ToString("0.00 ms"));
                    }
                }
            }
        }

        public static bool CompressJpeg(string path, Image img, int quality)
        {
            if (path.ToLower().Contains(".jpg"))
            {
                if (quality < 0 || quality > 100)
                    throw new ArgumentOutOfRangeException("quality must be between 0 and 100.");

                // Encoder parameter for image quality 
                EncoderParameter qualityParam = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, quality);
                // JPEG image codec 
                ImageCodecInfo jpegCodec = GetEncoderInfo("image/jpeg");
                EncoderParameters encoderParams = new EncoderParameters(1);
                encoderParams.Param[0] = qualityParam;
                img.Save(path, jpegCodec, encoderParams);
                img.Dispose();

                return true;
            }
            else {
                return false;
            }
        }

        private static ImageCodecInfo GetEncoderInfo(string mimeType)
        {
            // Get image codecs for all image formats 
            ImageCodecInfo[] codecs = ImageCodecInfo.GetImageEncoders();

            // Find the correct image codec 
            for (int i = 0; i < codecs.Length; i++)
                if (codecs[i].MimeType == mimeType)
                    return codecs[i];

            return null;
        }

        static string getFileName(string pathToFolder, string pathToFile)
        {
            return pathToFile.Replace(pathToFolder, "").Replace("\\", "");
        }

        static double getFileSize(string path)
        {
            if (File.Exists(path)) {
                return Convert.ToDouble(new FileInfo(path).Length / 1024);
            }
            else { return 0; }
        }

        static double countFilesSize(string[] files) {
            double sum = 0;

            foreach (string file in files) {
                sum += getFileSize(file);
            }

            return sum;
        }
    }
}