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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