gyawinzo.cs

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.IO;

namespace gyawinzo
{
    static class Program
    {
        static Point p1, p2;
        [STAThread]
        static void Main()
        {
            
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Form form = new Form();

     
            form.Opacity = 0.2;
            form.WindowState = FormWindowState.Maximized;
            form.FormBorderStyle = FormBorderStyle.None;
            form.TopMost = true;
            form.MouseClick += (sender, e) => {if (e.Button == MouseButtons.Right) ((Form)sender).Close();};
            form.MouseDown += (sender, e) => {
                if (e.Button == MouseButtons.Left)
                    p1 = e.Location;
            };
            form.MouseUp += (sender, e) => {
                if (e.Button == MouseButtons.Left)
                {
                    p2 = e.Location;
                    ((Form)sender).Close();
                    SaveImage();
                }
            };
            Application.Run(form);
        }

        static void SaveImage()
        {
            Rectangle rect = new Rectangle(p1, Size.Subtract((Size)p2, (Size)p1));
            if (rect.Size.Width * rect.Size.Height < 16) return;
            Bitmap bmp = new Bitmap(rect.Width, rect.Height);

            using (Graphics g = Graphics.FromImage(bmp))
            {
                g.CopyFromScreen(rect.X, rect.Y, 0, 0, rect.Size, CopyPixelOperation.SourceCopy);
            }
            DateTime now = DateTime.Now;
            string path = Environment.GetFolderPath(Environment.SpecialFolder.MyPictures);
            path += "\\Gyawinzo\\";
            path += now.ToString("yyyy-MM-dd");
            path += "\\";
            Directory.CreateDirectory(path);
            path += now.ToString("HH-mm-ss");
            path += ".png";
            bmp.Save(path);
        }
    }
}