CSS Overlay Animation on PNG Image

Question

Today i was customizing my website and i remembered a very nice CSS effect i saw a few months ago. I didnt find it on my Bookmarks.

The website had a Large logo with colors moving on it. After going on the Source Code, i saw that the Logo was a Black PNG file, and there was another Image, an Color Circle sppining on it, but there was some overlay effect that the colors of the circle only appear on the black parts of the logo.

anyone knows the website or how can i use this effect? to make some image appear only on non-trasparent parts of another image?

Thank you and best regards

Answer 1

Sounds like it might be CSS blending modes, which were introduced by Adobe and currently work in some builds of WebKit with a -webkit prefix.