> On 20 Jan 2015, at 11:31 am, Dean Jackson <[email protected]> wrote: > > Our designers at Apple often request a blending operation that is not > supported in the CSS Compositing and Blending specification: plus-darker. You > can find many examples and discussion of this mode if you Bing on the Google. > > We’d like to add this mode to Level 2. > > Details are here: http://en.wikipedia.org/wiki/Blend_modes#Addition > > The math is pretty simple: > > R = min(0, (1 - D) + (1 - S)) > > (We should maybe consider adding plus-lighter as well, and subtractive modes > based on designer feedback)
Aaaaaaand we almost immediately came across a need for plus-lighter, which is often called "additive". R = min(1, S + D) To give an example of where Apple uses these modes, it's used for blending our button glyphs when over the translucent materials e.g. the thing that swipes up from the bottom of the screen on iPads. Dean
