[css-media-queries-5] environment-blending use cases

[SCKelemen]

In Section 2.2 (Detecting the display technology: the environment-blending feature) of the Media Queries Level 5 specification, Issue 4 questions the need for the subtractive blending mode. Another consideration for this feature could include e-ink displays such as e-readers, as well as other e-ink display such as the e-ink barcodes. A subtractive mode, combined with the proposed Light-Level query and the screen update query could provide useful semantics for targeting e-ink displays. E-Ink displays are evolving, and now support multiple colors. They are composed of multiple layers of colored particles which overlap each layer. These color layers don't usually mix.

[tabatkins]

e-ink displays are "opaque" in this feature, no? The display is a combination of the (dark) ink and the (light) opaque display; there's not really any transparency. This is distinct from the subtractive example given, such as mirrors, where "white" is actually "whatever the mirror is showing".

[SCKelemen]

🤔
hmmm, I didn't read it that way. I guess that make sense, but let me consider it a bit longer.

[tabatkins]

It could be made clearer, definitely. The intent is to capture whether the screen colors are totally under the author's control, or if dark/light colors instead show something outside of their control.

[SCKelemen]

I agree. I think my previous suggestion applies given this information, but I the specification could probably be made clearer.