1. 程式人生 > 程式設計 >C# 使用BitBlt進行視窗抓圖的示例

C# 使用BitBlt進行視窗抓圖的示例

本文和C++使用BitBlt進行視窗抓圖對應,使用C#實現。

這種方式對1920*1080大小的視窗,一次抓圖的時間參考(VS2015+i5 9400F):低至2~3ms(平均4.3ms)。

參見:C#抓圖服務。

1、Win32封裝

Win32Consts

using System.ComponentModel;

namespace CaptureSharp
{
 public sealed class Win32Consts
 {
 public enum DibColorMode : uint
 {
  DIB_RGB_COLORS = 0x00,DIB_PAL_COLORS = 0x01,DIB_PAL_INDICES = 0x02
 }

 public enum BitmapCompressionMode : uint
 {
  BI_RGB = 0,BI_RLE8 = 1,BI_RLE4 = 2,BI_BITFIELDS = 3,BI_JPEG = 4,BI_PNG = 5
 }

 public enum RasterOperationMode : 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)
 }

 public enum PrintWindowMode : uint
 {
  [Description(
  "Only the client area of the window is copied to hdcBlt. By default,the entire window is copied.")]
  PW_CLIENTONLY = 0x00000001,[Description("works on windows that use DirectX or DirectComposition")]
  PW_RENDERFULLCONTENT = 0x00000002
 }
 }
}

Win32Types

using System.Runtime.InteropServices;

namespace CaptureSharp
{
 public sealed class Win32Types
 {
 [StructLayout(LayoutKind.Sequential)]
 public struct Point
 {
  public int x;
  public int y;

  public Point(int x,int y)
  {
  this.x = x;
  this.y = y;
  }
 }

 [StructLayout(LayoutKind.Sequential)]
 public struct Rect
 {
  public int Left; //最左座標
  public int Top; //最上座標
  public int Right; //最右座標
  public int Bottom; //最下座標

  public int Width => Right - Left;
  public int Height => Bottom - Top;
 }

 [StructLayout(LayoutKind.Sequential,Pack = 2)]
 public struct BitmapFileHeader
 {
  public ushort bfType;
  public uint bfSize;
  public ushort bfReserved1;
  public ushort bfReserved2;
  public uint bfOffBits;
 }

 [StructLayout(LayoutKind.Sequential)]
 public struct BitmapInfoHeader
 {
  public uint biSize;
  public int biWidth;
  public int biHeight;
  public ushort biPlanes;
  public ushort biBitCount;
  public uint biCompression;
  public uint biSizeImage;
  public int biXPelsPerMeter;
  public int biYPelsPerMeter;
  public uint biClrUsed;
  public uint biClrImportant;

  public void Init()
  {
  biSize = (uint)Marshal.SizeOf(this);
  }
 }

 [StructLayout(LayoutKind.Sequential,Pack = 1)]
 public struct RgbQuad
 {
  public byte rgbBlue;
  public byte rgbGreen;
  public byte rgbRed;
  public byte rgbReserved;
 }

 [StructLayout(LayoutKind.Sequential,Pack = 1)]
 public struct BitmapInfo
 {
  public BitmapInfoHeader bmiHeader;
  public RgbQuad bmiColors;
 }
 }
}

Win32Funcs

using System;
using System.Runtime.InteropServices;

namespace CaptureSharp
{
 public sealed class Win32Funcs
 {
 [DllImport("User32.dll",SetLastError = true)]
 public static extern IntPtr FindWindow(string lpClassName,string lpWindowName);

 [DllImport("user32.dll")]
 [return: MarshalAs(UnmanagedType.Bool)]
 public static extern bool GetWindowRect(IntPtr hWnd,out Win32Types.Rect lpRect);

 [DllImport("user32.dll")]
 public static extern bool GetClientRect(IntPtr hWnd,out Win32Types.Rect lpRect);

 [DllImport("user32.dll",EntryPoint = "GetWindowDC")]
 public static extern IntPtr GetWindowDC(IntPtr hWnd);

 [DllImport("gdi32.dll")]
 public static extern IntPtr CreateCompatibleDC(IntPtr hDc);

 [DllImport("gdi32.dll")]
 public static extern IntPtr CreateCompatibleBitmap(IntPtr hDc,int nWidth,int nHeight);

 [DllImport("gdi32.dll")]
 public static extern bool DeleteDC(IntPtr hDc);

 [DllImport("user32.dll")]
 public static extern IntPtr ReleaseDC(IntPtr hwnd,IntPtr hdc);

 [DllImport("gdi32.dll")]
 public static extern IntPtr CreateDIBSection(IntPtr hdc,ref Win32Types.BitmapInfo bmi,uint usage,out IntPtr ppvBits,IntPtr hSection,uint dwOffset);

 [DllImport("gdi32.dll")]
 public static extern IntPtr SelectObject(IntPtr hDc,IntPtr hObject);

 [DllImport("gdi32.dll")]
 public static extern bool DeleteObject(IntPtr hObject);

 [DllImport("gdi32.dll",SetLastError = true)]
 public static extern bool BitBlt(
  IntPtr hObject,int nXDest,int nYDest,int nHeight,IntPtr hObjectSource,int nXSrc,int nYSrc,uint dwRop);

 [DllImport("user32.dll")]
 public static extern bool PrintWindow(IntPtr hwnd,IntPtr hdcBlt,uint nFlags);
 }
}

2、DibCaptureHelper.cs

using System;

namespace CaptureSharp
{
 internal class DibCaptureHelper
 {
 public IntPtr BitmapPtr => _hBitmap;
 public Win32Types.BitmapInfo BitmapInfo => _bitmapInfo;
 public Win32Types.Rect WindowRect => _windowRect;
 public Win32Types.Rect ClientRect => _clientRect;
 public int BitmapDataSize => _bmpDataSize;

 private IntPtr _hWnd = IntPtr.Zero;
 private IntPtr _hScrDc = IntPtr.Zero;
 private IntPtr _hMemDc = IntPtr.Zero;
 private IntPtr _hBitmap = IntPtr.Zero;
 private IntPtr _hOldBitmap = IntPtr.Zero;
 private IntPtr _bitsPtr = IntPtr.Zero;

 private Win32Types.BitmapInfo _bitmapInfo;
 private Win32Types.Rect _windowRect;
 private Win32Types.Rect _clientRect;
 private int _bmpDataSize;

 public bool Init(string windowName)
 {
  var handle = Win32Funcs.FindWindow(null,windowName);
  if (handle.Equals(IntPtr.Zero))
  {
  return false;
  }

  return Init(handle);
 }

 public bool Init(IntPtr handle)
 {
  _hWnd = handle;

  //獲取視窗大小
  if (!Win32Funcs.GetWindowRect(_hWnd,out _windowRect)
  || !Win32Funcs.GetClientRect(_hWnd,out _clientRect))
  {
  return false;
  }

  _bmpDataSize = _clientRect.Width * _clientRect.Height * 3;

  //點陣圖資訊
  _bitmapInfo = new Win32Types.BitmapInfo {bmiHeader = new Win32Types.BitmapInfoHeader()};
  _bitmapInfo.bmiHeader.Init();
  _bitmapInfo.bmiHeader.biWidth = _clientRect.Width;
  _bitmapInfo.bmiHeader.biHeight = _clientRect.Height;
  _bitmapInfo.bmiHeader.biPlanes = 1;
  _bitmapInfo.bmiHeader.biBitCount = 24;
  _bitmapInfo.bmiHeader.biSizeImage = (uint) (_clientRect.Width * _clientRect.Height);
  _bitmapInfo.bmiHeader.biCompression = (uint) Win32Consts.BitmapCompressionMode.BI_RGB;

  _hScrDc = Win32Funcs.GetWindowDC(_hWnd);
  _hMemDc = Win32Funcs.CreateCompatibleDC(_hScrDc);
  _hBitmap = Win32Funcs.CreateDIBSection(_hMemDc,ref _bitmapInfo,(uint) Win32Consts.DibColorMode.DIB_RGB_COLORS,out _bitsPtr,IntPtr.Zero,0);
  _hOldBitmap = Win32Funcs.SelectObject(_hMemDc,_hBitmap);

  return true;
 }

 public void Cleanup()
 {
  if (_hBitmap.Equals(IntPtr.Zero))
  {
  return;
  }

  //刪除用過的物件
  Win32Funcs.SelectObject(_hMemDc,_hOldBitmap);
  Win32Funcs.DeleteObject(_hBitmap);
  Win32Funcs.DeleteDC(_hMemDc);
  Win32Funcs.ReleaseDC(_hWnd,_hScrDc);

  _hWnd = IntPtr.Zero;
  _hScrDc = IntPtr.Zero;
  _hMemDc = IntPtr.Zero;
  _hBitmap = IntPtr.Zero;
  _hOldBitmap = IntPtr.Zero;
  _bitsPtr = IntPtr.Zero;
 }

 public bool RefreshWindow()
 {
  var hWnd = _hWnd;
  Cleanup();
  return Init(hWnd);
 }

 public bool ChangeWindowHandle(string windowName)
 {
  Cleanup();
  return Init(windowName);
 }

 public bool ChangeWindowHandle(IntPtr handle)
 {
  Cleanup();
  return Init(handle);
 }

 public IntPtr Capture()
 {
  if (_hBitmap.Equals(IntPtr.Zero) || _hMemDc.Equals(IntPtr.Zero) || _hScrDc.Equals(IntPtr.Zero))
  {
  return IntPtr.Zero;
  }

  var ret = Win32Funcs.BitBlt(
  _hMemDc,_clientRect.Width,_clientRect.Height,_hScrDc,(uint) Win32Consts.RasterOperationMode.SRCCOPY);

  return ret ? _bitsPtr : IntPtr.Zero;
 }

 public bool Capture(out IntPtr bitsPtr,out int bufferSize,out Win32Types.Rect rect)
 {
  bitsPtr = _bitsPtr;
  bufferSize = _bmpDataSize;
  rect = _clientRect;

  if (_hBitmap.Equals(IntPtr.Zero) || _hMemDc.Equals(IntPtr.Zero) || _hScrDc.Equals(IntPtr.Zero))
  {
  return false;
  }

  var ret = Win32Funcs.BitBlt(
  _hMemDc,(uint) Win32Consts.RasterOperationMode.SRCCOPY);

  return ret;
 }
 }
}

以上就是C# 使用BitBlt進行視窗抓圖的示例的詳細內容,更多關於c# 視窗抓圖的資料請關注我們其它相關文章!