delphi的获取某坐标的颜色值

var
    PT : TPoint;
    C  : TColor;
    DC : HDC;
　 hwd : THandle;
    I : integer;
begin
    GetCursorPos(PT);
　 hwd := WindowFromPoint(PT);
    DC := GetDC(HWD);
    C := GetPixel(DC,PT.x,PT.y);
　// self.color := c;  //设置窗体颜色
    edit1.text := FORMAT($%.6x,[C]);
    //下面在指定窗口句柄下面绘制一条直线；
    for i := 0 to 800 do
    begin
         setPixel(DC,50,i,3cc8);
    end;
end;var
    PT