BCGSuite for MFC
BOOL CBCGPDrawManager::HighlightRect ( CRect  rect,
int  nPercentage = -1,
COLORREF  clrTransparent = (COLORREF)-1,
int  nTolerance = 0,
COLORREF  clrBlend = (COLORREF)-1 

Makes a rectangular area highlighted.

Nonzero if successful; otherwise 0.

Call this member function to highlight a rectangular area. If nPercentage is between 0 and 99 ([0, 99]), the HighlightRect function uses the alpha blending algorithm. If the nPercentage parameter is -1, it uses the default highlight level (e.g., Microsoft Office 2000-style menus highlighting). If nPercentage is 100, it does nothing and returns TRUE.

rectSpecifies a rectangular area to fill.
nPercentageSpecifies the transparency percentage.
clrTransparentSpecifies the transparent color.
nToleranceColor tolerance. Should be within 0-255 range.
clrBlendBase blending color.