C#截取屏幕↑

2024-07-21 02:19:29

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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.([email protected])

///
/// 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 // handle to object
);

[dllimport("gdi32.dll")]
public static extern int bitblt(
intptr hdcdest, // handle to destination dc
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
uint32 dwrop // raster operation code
);

[dllimport("gdi32.dll")]
public static extern int deletedc(
intptr hdc // handle to dc
);

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