/*
	ScreenCapturer C# source
	Lee Felarca
	http://www.zeropointnine.com/blog
	v0.9 - 2009-04-18

	Runs in the background, and feeds screencapture image data 
	to external processes via standard I/O 

	Source code licensed under a Creative Commons Attribution 3.0 License.
	http://creativecommons.org/licenses/by/3.0/
	Some Rights Reserved. Improvements made to this class are encouraged.
*/

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Drawing.Imaging;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.IO;
using System.Runtime.InteropServices;
using System.Timers;


namespace ScreenCapturer
{
    public partial class ScreenCapturer : Form
    {
        public const string sendImage_COMMAND = "GET";
        public const string EXIT_COMMAND = "EXIT";
        public const uint STARTCODE = 9999999;
        public const uint ENDCODE = 6666666;
        
        private byte[] _ba;

        public ScreenCapturer()
        {
            InitializeComponent();

            go();
        }

        private void go()
        {
            string s;
            do
            {
                s = System.Console.In.ReadLine();
            }
            while (s == null || s.Length == 0); // does not lock CPU (despite appearances)

            string[] a = s.Split(' ');
            string command = a[0];

            switch (command)
            {
                case sendImage_COMMAND:
                    if (a.Length != 5) break;
                    int w = Int32.Parse(a[1]);
                    int h = Int32.Parse(a[2]);
                    int offx = Int32.Parse(a[3]);
                    int offy = Int32.Parse(a[4]);
                    sendImage(w, h, offx, offy);
                    break;

                case EXIT_COMMAND:
                    Application.Exit();
                    break;
            }

            go();
        }

        private void sendImage(int w, int h, int offx, int offy)
        {
            _ba = getScreenCapture(w, h, offx, offy); 

            Stream console = Console.OpenStandardOutput();
            BinaryWriter binaryWriter = new BinaryWriter(console);

            // compose 'header' and send in one chunk
            MemoryStream msh = new MemoryStream();
            BinaryWriter bwh = new BinaryWriter(msh);
            bwh.Write(STARTCODE); // start code
            bwh.Write((int)w); // image width
            bwh.Write((int)h); // image height
            byte[] bah = msh.ToArray();
            binaryWriter.Write(bah);

            // dump image info, all at once
            binaryWriter.Write(_ba);

            // send termination code
            binaryWriter.Write(ENDCODE);
        }

        private byte[] getScreenCapture(int w, int h, int offx, int offy)
        {
            int startTime = DateTime.Now.Millisecond;

            Bitmap bitmap = new Bitmap(w, h);
            Graphics g = Graphics.FromImage(bitmap);
            g.CopyFromScreen(new Point(offx, offy), Point.Empty, new Size(w, h)); // * how expensive is this?
            byte[] ba = bitmapToBytes(bitmap);

            // benchmark info
            int constructionTime = DateTime.Now.Millisecond - startTime;
            System.Diagnostics.Trace.WriteLine("Time required to compose data: " + constructionTime);

            return ba;
        }

        private unsafe byte[] bitmapToBytes(Bitmap bmp)
        {
            BitmapData bData = bmp.LockBits(new Rectangle(new Point(), bmp.Size),
                ImageLockMode.ReadOnly,
                PixelFormat.Format32bppArgb);

            // number of bytes in the bitmap
            int byteCount = bData.Stride * bmp.Height;
            byte[] bmpBytes = new byte[byteCount];

            // Copy the locked bytes from memory
            Marshal.Copy(bData.Scan0, bmpBytes, 0, byteCount);

            // don't forget to unlock the bitmap
            bmp.UnlockBits(bData);

            return bmpBytes;
        }
    }
}