ImageGear for C and C++ on Windows v19.1 - Updated
Functional Lights Effects
User Guide > How to Work with... > Image Processing and Cleanup > Special Effects > Functional Lights Effects

Functional Lights functions change the colors of an image according to the pattern of a sine wave, or an application-defined pattern. The image will appear to have circles or bars of light and/or shadow overlaid on top of it.

Original

Directional Light Effect

Radial Light Effect

Free Directional Light Effect