(四)创建抓取图象的单元文件ScrnCpt
unit ScrnCpt;
interface
uses windows,forms,controls,classes,Graphics; function CaptureScreenRect(ARect:TRect):TBitmap; function CaptureScreen:TBitmap; function CaptureClientImage(Control:TControl):TBitmap; function CaptureControlImage(Control:TControl):TBitmap; function CaptureWindowImage(Wnd:HWND):TBitmap;
implementation
function CaptureScreenRect(ARect:TRect):TBitmap; var ScreenDC:HDC; //设备描述表的句柄 begin result:=TBitmap.Create ; with Result,ARect do begin Width :=Right-left; Height:=Bottom-Top; ScreenDC:=GetDC(0); //获取一个窗口的设备描述表的句柄,0参数返回屏幕窗口设备描述表的句柄 try //BOOL BitBlt(hdcDest,nXDest,nYDest,nWidth,nHeight,hdcSrc,nXSrc,nYSrc,dwRop) //把位图从源设备描述表hdcSrc复制到目标设备描述表hdcDest, //光栅操作码dwRop指定了 源图的组合方式 BitBlt(Canvas.Handle ,0,0,Width,Height,ScreenDC,left,top,SRCCOPY); finally ReleaseDC(0,ScreenDC); end; end; end;
//全屏抓图 function CaptureScreen:TBitmap; begin with Screen do result:=CaptureScreenRect(Rect(0,0,width,height)); end;
//抓取一个窗体或控件的客户区图象 function CaptureClientImage(Control:TControl):TBitmap; begin //Control.ClientOrigin是控件客户区的左上角位置。x,y是 ClientOrigin的变量 with Control,Control.ClientOrigin do result:=CaptureScreenRect(Bounds(x,y,ClientWidth,ClientHeight)); end;
// 抓取一整个窗体或控件 function CaptureControlImage(Control:TControl):TBitmap; begin with Control do if Parent=nil then //无父窗体,根据它的位置,直接抓取 result:=CaptureScreenRect(Bounds(left,top,width,height)) else //有父窗体,把它转化为相对于屏幕坐标,再 抓取 with Parent.ClientToScreen(Point(Left,top))do result:=CaptureScreenRect(Bounds(x,y,width,height)); end;
//根据窗体句柄进行抓取 function CaptureWindowImage(Wnd:HWND):TBitmap; var R:TRect; begin GetWindowRect(wnd,R); //把窗口句柄指定的窗口坐标放入TRect result:=CaptureScreenRect(R); end;
end.
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