WinAPI: CreatePenIndirect - 根据笔的参数结构建立画笔

//声明:

CreatePenIndirect(

  const LogPen: TLogPen {笔结构}

): HPEN;                {返回笔句柄}



//TLogPen 是 tagLOGPEN 结构的重定义: 

tagLOGPEN = packed record

  lopnStyle: UINT;     {笔样式}

  lopnWidth: TPoint;   {笔宽; 只需要 TPoint.X}

  lopnColor: COLORREF; {颜色}

end;



//lopnStyle 可选值:

PS_SOLID       = 0; {实线}

PS_DASH        = 1; {段线; 要求笔宽<=1}

PS_DOT         = 2; {点线; 要求笔宽<=1}

PS_DASHDOT     = 3; {线、点; 要求笔宽<=1}

PS_DASHDOTDOT  = 4; {线、点、点; 要求笔宽<=1}

PS_NULL        = 5; {不可见}

PS_INSIDEFRAME = 6; {实线; 但笔宽是向里扩展}


 
   




//举例:

procedure TForm1.FormPaint(Sender: TObject);

var

  p: TLogPen;

  PH1,PH2: HPEN;

begin

  p.lopnStyle := PS_DOT;

  p.lopnWidth.X := 0;    {给笔宽赋值0, 会使用1像素笔宽}

  p.lopnColor := clRed;



  PH1 := CreatePenIndirect(p);

  PH2 := SelectObject(Canvas.Handle, PH1);

  Ellipse(Canvas.Handle, 20, 20, 96,132);



  DeleteObject(PH1);

  DeleteObject(PH2);

end;


 
   




//效果图:

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