Q111580: BUG: Some ROP Codes Cause Inconsistent Polygon() Line Segments

Article: Q111580
Product(s): Microsoft Windows Software Development Kit
Version(s): WINDOWS:3.0,3.1
Operating System(s): 
Keyword(s): 
Last Modified: 07-NOV-1999

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The information in this article applies to:

- Microsoft Windows Software Development Kit (SDK) versions 3.0, 3.1 
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SYMPTOMS
========

When a ROP (raster operation) such as R2_XORPEN or R2_NOT is used with the
Polygon() function, the line segments may be inconsistent; they may appear
highlighted or ragged when they should appear smooth. This may be more apparent
when the polygon is filled with a gray brush (80h).

CAUSE
=====

The border does not overlap the interior fill precisely. Polygonal filling works
successfully, but the XOR operation with the pen shows that the overlap between
border and fill is not completely consistent.

STATUS
======

Microsoft has confirmed this to be a bug in Windows versions 3.0 and 3.1. We are
researching this problem and will post new information here in the Microsoft
Knowledge Base as it becomes available.

MORE INFORMATION
================

The following function demonstrates the problem:

  int PASCAL TestProc( HWND hWnd )
  {
      HDC hDC;
      HBRUSH hGrayBrush, hOldBrush;
      POINT aPoints[3];

      hGrayBrush = CreateSolidBrush(RGB(128,128,128));

      aPoints[0].x = 50;
      aPoints[0].y = 10;
      aPoints[1].x = 250;
      aPoints[1].y = 50;
      aPoints[2].x = 125;
      aPoints[2].y = 130;

      hDC = GetDC(hWnd);

      // default pen, brush, and ROP2
      Polygon(hDC, aPoints, sizeof(aPoints) / sizeof(POINT));

      // default pen, gray brush, XORPEN ROP2
      hOldBrush = SelectObject(hDC, hGrayBrush);
      SetROP2(hDC, R2_XORPEN);
      Polygon(hDC, aPoints, sizeof(aPoints) / sizeof(POINT));

      // clean up
      SelectObject(hDC, hOldBrush);
      ReleaseDC(hWnd, hDC);
      return 1;
  }

Additional query words: buglist3.00 buglist3.10 3.00 3.10 ropcode code uneven

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Keywords          :  
Technology        : kbAudDeveloper kbWin3xSearch kbSDKSearch kbWinSDKSearch kbWinSDK300 kbWinSDK310
Version           : WINDOWS:3.0,3.1

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