活用C#截取计算机屏幕
日期：2011-06-19 浏览次数：20574 次
今天无聊翻代码,翻出来一个以前写的C#截屏的函数...拿出来和大家共享一下.
这段代码是参照网上一段截屏的C++代码改写的.只不过把API都声明了一下而已.
声明的各API也附后.以供参照.如有问题欢迎指出.
作者：AppleDotnet
///
/// 截取部分屏幕
///
/// 左上角
/// 右下角
/// 是否全屏幕
/// 返回值Bitmap
public static Bitmap GetPartScreen(Point P1,Point P2,bool Full)
{
IntPtr hscrdc,hmemdc;
IntPtr hbitmap,holdbitmap;
int nx,ny,nx2,ny2;
nx=ny=nx2=ny2=0;
int nwidth, nheight;
int xscrn, yscrn;
hscrdc = CreateDC("DISPLAY", null, null, 0);//创建DC句柄
hmemdc = CreateCompatibleDC(hscrdc);//创建一个内存DC
xscrn = GetDeviceCaps(hscrdc, GetDeviceCapsIndex.HORZRES);//获取屏幕宽度
yscrn = GetDeviceCaps(hscrdc, GetDeviceCapsIndex.VERTRES);//获取屏幕高度
if(Full)//如果是截取整个屏幕
{
nx = 0;
ny = 0;
nx2 = xscrn;
ny2 = yscrn;
}
else
{
nx = P1.X;
ny = P1.Y;
nx2 =P2.X;
ny2 =P2.Y;
//检查数值合法性
if(nx<0)nx = 0;
if(ny<0)ny = 0;
if(nx2>xscrn)nx2 = xscrn;
if(ny2>yscrn)ny2 = yscrn;
}
nwidth = nx2 - nx;//截取范围的宽度
nheight = ny2 - ny;//截取范围的高度
hbitmap = CreateCompatibleBitmap(hscrdc, nwidth, nheight);//从内存DC复制到hbitmap句柄
holdbitmap = SelectObject(hmemdc, hbitmap);
BitBlt(hmemdc, 0, 0, nwidth, nheight,hscrdc, nx, ny,(UInt32)0xcc0020);
hbitmap = SelectObject(hmemdc, holdbitmap);
DeleteDC(hscrdc);//删除用过的对象
DeleteDC(hmemdc);//删除用过的对象
return Bitmap.FromHbitmap(hbitmap);//用Bitmap.FromHbitmap从hbitmap返回Bitmap
}
所用到的API声明:
[DllImport("gdi32.dll")]
public static extern IntPtr CreateDC(
string lpszDriver, // driver name
string lpszDevice, // device name
string lpszOutput, // not used; should be NULL
Int64 lpInitData // optional printer data
);
[DllImport("gdi32.dll")]
public static extern IntPtr CreateCompatibleDC(
IntPtr hdc // handle to DC
);
[DllImport("gdi32.dll")]
public static extern int GetDeviceCaps(
IntPtr hdc, // handle to DC
GetDeviceCapsIndex nIndex // index of capability
);
[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 // hand
