Microsoft KB Archive/111580

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BUG: Some ROP Codes Cause Inconsistent Polygon Line Segments

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Q111580

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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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Technology : kbAudDeveloper kbWin3xSearch kbSDKSearch kbWinSDKSearch kbWinSDK300 kbWinSDK310