BUG: XORing May Not Erase Lines in SVGA Modes

Q109680

7.00 | 1.00 1.50 MS-DOS | WINDOWS kbtool kbbuglist ---------------------------------------------------------------------- The information in this article applies to: - Microsoft C/C++ for MS-DOS, version 7.0 - Microsoft Visual C++ for Windows, versions 1.0 and 1.5 ---------------------------------------------------------------------- SYMPTOMS ======== Using the GRAPHICS.LIB function _setwritemode() with the _GXOR constant may not produce the expected output when drawing lines using _lineto() or _lineto_w(). Specifically, drawing a line using the XOR write mode directly on top of another line may not erase the original line. This problem occurs only in super VGA modes. STATUS ====== Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available. MORE INFORMATION ================ The sample program below illustrates the problem: Sample Code ----------- #include <graph.h> #include <conio.h> void main(void) { if (_setvideomode(_VRES256COLOR)==0) exit(0); _clearscreen(_GCLEARSCREEN); _setwritemode(_GXOR); _setcolor(7); _moveto(320,240); _lineto(177,378); _getch(); _moveto(320,240); _lineto(177,378); _getch(); _setvideomode(_DEFAULTMODE); } Additional reference words: 1.00 1.50 7.00 8.00 8.00c KBCategory: kbtool kbbuglist KBSubcategory: GraphicsIss

Keywords : kb16bitonly
Issue type : kbbug
Technology : kbVCsearch kbAudDeveloper kbPTProdChange kbvc150 kbvc100 kbZNotKeyword3 kbCVC700DOS


Last Reviewed: May 6, 2001
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