| 主 题： | 再散100分,关于摄像头捕获照相问题,还没有解决,解决了再加分 | |
| 作 者： | nangangshi (小米) | |
| 等 级： |  |
|
| 信 誉 值： | 98 | |
| 所属社区： | .NET技术 C# | |
| 问题点数： | 100 | |
| 回复次数： | 7 | |
| 发表时间： | 2006-5-2 20:39:09 |
看起来很难的问题，其实实现起来很简单，你用捕获当前窗口的图像，得到一个BitMap对象，就像那种抓图软件一样，再根据"矩形框"的位置，剪下所抓的图片的相应部份，对BitMap对象的操作是很简单的，抓图稍微麻烦一点，用到的API函数有：CreateDC,GetWindowDC,PrintWindow,SelectObject,BitBlt等等，这些都是gdi32.dll里的。我写一段代码在下面以供参考:
public class Snap
{
[DllImport("gdi32.dll")]
public static extern IntPtr CreateDC(
string lpszDriver, // driver name驱动名
string lpszDevice, // device name设备名
string lpszOutput, // not used; should be NULL
IntPtr lpInitData // optional printer data
);
[DllImport("gdi32.dll")]
public static extern int BitBlt(
IntPtr hdcDest, // handle to destination DC目标设备的句柄
int nXDest, // x-coord of destination upper-left corner目标对象的左上角的X坐标
int nYDest, // y-coord of destination upper-left corner目标对象的左上角的Y坐标
int nWidth, // width of destination rectangle目标对象的矩形宽度
int nHeight, // height of destination rectangle目标对象的矩形长度
IntPtr hdcSrc, // handle to source DC源设备的句柄
int nXSrc, // x-coordinate of source upper-left corner源对象的左上角的X坐标
int nYSrc, // y-coordinate of source upper-left corner源对象的左上角的Y坐标
UInt32 dwRop // raster operation code光栅的操作值
);
[DllImport("gdi32.dll")]
public static extern IntPtr CreateCompatibleDC(
IntPtr hdc // handle to DC
);
[DllImport("gdi32.dll")]
public static extern IntPtr CreateCompatibleBitmap(
IntPtr hdc, // handle to DC
int nWidth, // width of bitmap, in pixels
int nHeight // height of bitmap, in pixels
);
[DllImport("gdi32.dll")]
public static extern IntPtr SelectObject(
IntPtr hdc, // handle to DC
IntPtr hgdiobj // handle to object
);
[DllImport("gdi32.dll")]
public static extern int DeleteDC(
IntPtr hdc // handle to DC
);
[DllImport("user32.dll")]
public static extern bool PrintWindow(
IntPtr hwnd, // Window to copy,Handle to the window that will be copied.
IntPtr hdcBlt, // HDC to print into,Handle to the device context.
UInt32 nFlags // Optional flags,Specifies the drawing options. It can be one of the following values.
);
[DllImport("user32.dll")]
public static extern IntPtr GetWindowDC(
IntPtr hwnd
);
public Snap()
{
//
// TODO: 在此处添加构造函数逻辑
//
}
public static Bitmap GetWindow(IntPtr hWnd)
{
IntPtr hscrdc = GetWindowDC(hWnd);
MainC.RECT rc=MainC.GetWindowSize(hWnd);
int wh=rc.Width();
int ht=rc.Height();
IntPtr hbitmap = CreateCompatibleBitmap(hscrdc, wh, ht);
IntPtr hmemdc = CreateCompatibleDC(hscrdc);
SelectObject(hmemdc, hbitmap);
PrintWindow(hWnd, hmemdc, 0);
Bitmap bmp = Bitmap.FromHbitmap(hbitmap);
DeleteDC(hscrdc);//删除用过的对象
DeleteDC(hmemdc);//删除用过的对象
return bmp;
}
}