{Source} C# Simple Screen Snapping Program.

This is NOT my tutorial, I am simply sharing this with the public:​

​

Just make a new project, and replace the code in Program.cs.​

Code:

using System;
using System.Windows.Forms;
using System.Drawing;
using System.Drawing.Imaging;
 
namespace screen_snipping
{
    static class Program
    {
        private static Image fullDesktop;
        private static Image partIamge;
        private static Form backgroundForm;
        private static PictureBox picbox1;
 
        private static Point mouseDownAt;
        private static Point mouseIsAt;
        private static bool isMouseDown = false;
 
        private static Color backgroundColor = Color.DarkGray;
        private static int backgroundAlpha = 150;
        private static Color outlineColor = Color.Red;
        private static int outlineWidth = 1;
 
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
 
            fullDesktop = CaptureScreen;
            Initialize();
 
            Application.Run(backgroundForm);
        }
 
        private static void Initialize()
        {
            backgroundForm = new Form();
            backgroundForm.FormBorderStyle = FormBorderStyle.None;
            backgroundForm.WindowState = FormWindowState.Maximized;
            backgroundForm.Cursor = Cursors.Cross;
 
            picbox1 = new PictureBox();
            picbox1.Size = Screen.FromControl(backgroundForm).Bounds.Size;
            picbox1.Location = new Point(0, 0);
            picbox1.Image = fullDesktop;
            picbox1.BorderStyle = BorderStyle.None;
            picbox1.Paint += new PaintEventHandler(OnPaint);
            picbox1.MouseDown += new MouseEventHandler(OnMouseDown);
            picbox1.MouseMove += new MouseEventHandler(OnMouseMove);
            picbox1.MouseUp += new MouseEventHandler(OnMouseUp);
            backgroundForm.Controls.Add(picbox1);
        }
 
        private static void OnPaint(object sender, PaintEventArgs e)
        {
            SolidBrush opaqueWhiteBrush = new SolidBrush(Color.FromArgb(backgroundAlpha, backgroundColor.R, backgroundColor.G, backgroundColor.B));
            e.Graphics.FillRectangle(opaqueWhiteBrush, 0, 0, picbox1.Width, picbox1.Height);
 
            if (isMouseDown)
            {
                Rectangle pos = getMouseMoveRect;
                e.Graphics.DrawRectangle(new Pen(outlineColor, outlineWidth), new Rectangle(pos.X - outlineWidth, pos.Y - outlineWidth, pos.Width + outlineWidth, pos.Height + outlineWidth));
                e.Graphics.DrawImage(partIamge, pos.Location);
 
                string displayText = "W: " + pos.Width + " H: " + pos.Height;
                Font font = new Font("Arial", 10, FontStyle.Bold, GraphicsUnit.Pixel);
                e.Graphics.DrawString(displayText, font, Brushes.White, pos.X, pos.Y - font.Size - 6, StringFormat.GenericDefault);
            }
        }
 
        private static void OnMouseDown(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Right && !isMouseDown)
            {
                Application.Exit();
            }
            else if (e.Button == MouseButtons.Left)
            {
                mouseDownAt = e.Location;
                Cursor.Position = new Point(e.Location.X + 1, e.Location.Y + 1);
                mouseIsAt = new Point(e.Location.X + 1, e.Location.Y + 1);
                partIamge = ((Bitmap)fullDesktop).Clone(getMouseMoveRect, fullDesktop.PixelFormat);
                isMouseDown = true;
                picbox1.Refresh();
            }
        }
 
        private static void OnMouseMove(object sender, MouseEventArgs e)
        {
            if (isMouseDown)
            {
                mouseIsAt = e.Location;
                Rectangle rect = getMouseMoveRect;
                if (rect.Width != 0 && rect.Height != 0)
                {
                    partIamge = ((Bitmap)fullDesktop).Clone(rect, fullDesktop.PixelFormat);
                    picbox1.Refresh();
                }
            }
        }
 
        private static void OnMouseUp(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                bool hasMoved = false;
 
                if (isMouseDown)
                {
                    hasMoved = true;
                    isMouseDown = false;
                }
 
                SaveFileDialog sfd = new SaveFileDialog();
                sfd.Filter = "PNG image (*.png)|*.png";
                if (sfd.ShowDialog() == DialogResult.OK)
                {
                    partIamge.Save(sfd.FileName, ImageFormat.Png);
                }
                else
                {
                    hasMoved = false;
                    picbox1.Refresh();
                }
 
                if (hasMoved)
                    Application.Exit();
            }
        }
 
        private static Rectangle getMouseMoveRect
        {
            get
            {
                int x = 0;
                int y = 0;
                int width = 0;
                int height = 0;
 
                if (mouseIsAt.X > mouseDownAt.X)
                {
                    x = mouseDownAt.X;
                    width = mouseIsAt.X - mouseDownAt.X;
                }
                else
                {
                    x = mouseIsAt.X;
                    width = mouseDownAt.X - mouseIsAt.X;
                }
 
                if (mouseIsAt.Y > mouseDownAt.Y)
                {
                    y = mouseDownAt.Y;
                    height = mouseIsAt.Y - mouseDownAt.Y;
                }
                else
                {
                    y = mouseIsAt.Y;
                    height = mouseDownAt.Y - mouseIsAt.Y;
                }
 
                return new Rectangle(x, y, width, height);
            }
        }
 
        private static Image CaptureScreen
        {
            get
            {
                Bitmap image = new Bitmap(Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height);
                using (Graphics g = Graphics.FromImage(image))
                {
                    g.CopyFromScreen(Screen.PrimaryScreen.Bounds.X,
                             Screen.PrimaryScreen.Bounds.Y,
                             0, 0,
                             image.Size,
                             CopyPixelOperation.SourceCopy);
                }
 
                return image;
            }
        }
    }
}