[Bug 6842] New: DrawFocusRect code correction

[Wine Bugs]

http://bugs.winehq.org/show_bug.cgi?id=6842

Summary: DrawFocusRect code correction
           Product: Wine
           Version: 0.9
          Platform: Other
        OS/Version: other
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P5
         Component: wine-user
        AssignedTo: [e-mail]
        ReportedBy: [e-mail]

Here are the code excerpts for the most correct and fastest implementation of
DrawFocusRect. The performance is not substantially slower with caching disabled
so for simplicity you may not want to implement caching right away.

#define HBR_CACHE (TRUE) // set to TRUE to enable caching, FALSE to disable caching
#if HBR_CACHE
HBRUSH g_hbrushFocus=NULL;
#else
#define g_hbrushFocus hbrushFocus // Define this to disable caching
#endif

// ...

BOOL fResult=FALSE;
#if 1
    HBRUSH hbrushOld;
#if !HBR_CACHE
    HBRUSH hbrushFocus;
#endif
    if (!HBR_CACHE || !g_hbrushFocus) { // caching the pattern allows us to
exactly match the performance of DrawFocusRect().
      static const unsigned char
aBitPixels[]={0x55,0,0xAA,0,0x55,0,0xAA,0,0x55,0,0xAA,0,0x55,0,0xAA,0};
      HBITMAP hbitmapFocus=CreateBitmap(8,8,1,1,&aBitPixels); // sizes other
than 8x8 are always slower and can be less compatible
      g_hbrushFocus=CreatePatternBrush(hbitmapFocus); // SetTextColor/SetBkColor
are what's used here
      DeleteBitmap(hbitmapFocus);
    }
    hbrushOld=SelectObject(hdc,g_hbrushFocus);
    if (hbrushOld) {
      HRGN hrgnFocus=CreateRectRgn(prc->left,prc->top,prc->right,prc->bottom);
// this can't be cached because every caller has a different size rectangle.
Besides we're already matching the speed of the real DrawFocusRect
      HRGN
hrgnInner=CreateRectRgn(prc->left+1,prc->top+1,prc->right-1,prc->bottom-1);
      CombineRgn(hrgnFocus,hrgnFocus,hrgnInner,RGN_DIFF);
      DeleteRgn(hrgnInner);
      SelectObject(hdc,hrgnFocus);
      fResult=PatBlt(hdc, prc->left, prc->top, prc->right-prc->left,
prc->bottom-prc->top,PATINVERT); // 4 PatBlt without a clip region are slower
and will not produce the correct right/bottom transitions
      DeleteRgn(hrgnFocus);
      SelectObject(hdc,hbrushOld);
      SelectClipRgn(hdc,NULL);
    }
#if !HBR_CACHE
    DeleteBrush(hbrushFocus); // for caching this is done in WM_DESTROY
#endif

// ...

#if HBR_CACHE
  case WM_DESTROY:
    if (g_hbrushFocus) DeleteBrush(g_hbrushFocus); break;
#endif