在c#中使用bitblt显示图片

使用bitblt比DrawImage有更好的性能

using AForge.Video.DirectShow;

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Drawing.Imaging;

using System.Linq;

using System.Runtime.InteropServices;

using System.Text;

using System.Windows.Forms;



namespace HongYing.Test

{

    public partial class BitBltTester : Form

    {

        private VideoCaptureDevice videoSource;



        public BitBltTester()

        {

            InitializeComponent();



#if GDIPlus

            SetStyle(ControlStyles.OptimizedDoubleBuffer, true); //默认启动双缓冲

            SetStyle(ControlStyles.DoubleBuffer, true);

            SetStyle(ControlStyles.UserPaint, true);

            SetStyle(ControlStyles.ResizeRedraw, true);

            SetStyle(ControlStyles.AllPaintingInWmPaint, true); // 禁止擦除背景.

#endif

            var videoDevices = new FilterInfoCollection(FilterCategory.VideoInputDevice);

            videoSource = new VideoCaptureDevice(videoDevices[1].MonikerString);

            videoSource.NewFrame += _videoSource_NewFrame;

            videoSource.Start();

        }



        protected override void OnPaint(PaintEventArgs e)

        {

            base.OnPaint(e);



#if GDIPlus

            if (frame != null)

            {

                e.Graphics.DrawImage(frame, ClientRectangle);

            }

#else



#endif

        }



        public enum TernaryRasterOperations : uint

        {

            SRCCOPY = 0x00CC0020,

            SRCPAINT = 0x00EE0086,

            SRCAND = 0x008800C6,

            SRCINVERT = 0x00660046,

            SRCERASE = 0x00440328,

            NOTSRCCOPY = 0x00330008,

            NOTSRCERASE = 0x001100A6,

            MERGECOPY = 0x00C000CA,

            MERGEPAINT = 0x00BB0226,

            PATCOPY = 0x00F00021,

            PATPAINT = 0x00FB0A09,

            PATINVERT = 0x005A0049,

            DSTINVERT = 0x00550009,

            BLACKNESS = 0x00000042,

            WHITENESS = 0x00FF0062,

            CAPTUREBLT = 0x40000000 //only if WinVer >= 5.0.0 (see wingdi.h)

        }



        Bitmap frame;

        private const int SRCCOPY = 0xCC0020; 



        void _videoSource_NewFrame(object sender, AForge.Video.NewFrameEventArgs eventArgs)

        {

             frame = (Bitmap)eventArgs.Frame.Clone();



#if GDIPlus

            Invalidate();

#else

             Bitmap sourceBitmap = frame;

             Graphics sourceGraphics = Graphics.FromImage(frame);



             Graphics destGraphics = CreateGraphics();





             IntPtr destDC = destGraphics.GetHdc();

             IntPtr destCDC = CreateCompatibleDC(destDC);

             IntPtr oldDest = SelectObject(destCDC, IntPtr.Zero);



             IntPtr sourceDC = sourceGraphics.GetHdc();

             IntPtr sourceCDC = CreateCompatibleDC(sourceDC);

             IntPtr sourceHB = sourceBitmap.GetHbitmap();

             IntPtr oldSource = SelectObject(sourceCDC, sourceHB);



             int success = StretchBlt(destDC, 0, 0, Width, Height, sourceCDC, 0, 0, sourceBitmap.Width, sourceBitmap.Height, (int)TernaryRasterOperations.SRCCOPY);



             SelectObject(destCDC, oldDest);

             SelectObject(sourceCDC, oldSource);



             DeleteObject(destCDC);

             DeleteObject(sourceCDC);

             DeleteObject(sourceHB);



             destGraphics.ReleaseHdc();

             sourceGraphics.ReleaseHdc();

#endif

            eventArgs.Frame.Dispose();

        }

        [System.Runtime.InteropServices.DllImportAttribute("gdi32.dll")]

        public static extern IntPtr CreateCompatibleDC(IntPtr hdc);

        [System.Runtime.InteropServices.DllImport("gdi32.dll")]

        private static extern int BitBlt(

        IntPtr hdcDest,     // handle to destination DC (device context)

        int nXDest,         // x-coord of destination upper-left corner

        int nYDest,         // y-coord of destination upper-left corner

        int nWidth,         // width of destination rectangle

        int nHeight,        // height of destination rectangle

        IntPtr hdcSrc,      // handle to source DC

        int nXSrc,          // x-coordinate of source upper-left corner

        int nYSrc,          // y-coordinate of source upper-left corner

        System.Int32 dwRop  // raster operation code

        );



        [System.Runtime.InteropServices.DllImportAttribute("gdi32.dll")]

        public static extern IntPtr SelectObject(IntPtr hdc, IntPtr obj);



        [System.Runtime.InteropServices.DllImportAttribute("gdi32.dll")]

        public static extern void DeleteObject(IntPtr obj);



        [DllImport("gdi32", EntryPoint = "StretchBlt")]

        public static extern int StretchBlt(

                IntPtr hdc,

                int x,

                int y,

                int nWidth,

                int nHeight,

                IntPtr hSrcDC,

                int xSrc,

                int ySrc,

                int nSrcWidth,

                int nSrcHeight,

                int dwRop

        );

    }

}

参考:experts-exchange.com