BCGControlBar Pro for MFC
void CBCGPHotSpotImageCtrl::SetHighlightHotArea ( int  nPercentage,
int  nTolerance = 0 

Defines an area to highlight.

Uses highlight percentage and color tolerance instead of hot image in order to highlight hot spots.

The function identifies areas to highlight in the main bitmap using nTolerance, e.g. it takes all colors within a color range calculated from transparent color and nTolerance value and ignores them, while the rest of colors are modified according to nPercentage value.

nPercentageHighlight percentage.
nToleranceColor tolerance. Should be between 0 and 255.