- From: Mounir Lamouri via GitHub <sysbot+gh@w3.org>
- Date: Tue, 31 Jan 2017 18:53:46 +0000
- To: public-css-archive@w3.org
mounirlamouri has just created a new issue for https://github.com/w3c/csswg-drafts: == [cssom-view] Make colorDepth/pixelDepth return useful information again == **Context:** this is related to the [Screen](https://drafts.csswg.org/cssom-view/#screen) interface, in particular the [colorDepth](https://drafts.csswg.org/cssom-view/#dom-screen-colordepth) and [pixelDepth](https://drafts.csswg.org/cssom-view/#dom-screen-pixeldepth) **Some bug history:** * https://www.w3.org/Bugs/Public/show_bug.cgi?id=17522 * https://www.w3.org/Bugs/Public/show_bug.cgi?id=14071 I am suggesting that we do the following changes: - `colorDepth` and `pixelDepth` continue to return the same value; - `colorDepth` and `pixelDepth` should return the number of bits allocated to colors on the output device or an approximation to the best of the UA's knowledge; - 24 is to be used as a default value for privacy considerations or when the UA can't find the value; - the `color` MQ should return a consistent values with `colorDepth` and `pixelDepth` (eg. 8 when the properties return 24 or 10 when 30 is returned by the properties) We could also recommend 24 to be used if the value would be below 24. However, Blink already exposes monochrome in the `color` MQ so there might be benefit of keeping consistency between APIs in some cases where the value would be below 24. The purpose for this change is for websites to be able to detect whether it is worth providing content that would require high color depth output. The main concern would be fingerprinting. The treat seems fairly weak compared to the current fingerprinting surface on the Web. It will most likely add one or two bits of entropy (24/30/48) which can probably be linked to other properties of the display (CSS color gamut, screen size, etc), thus likely reducing the practical benefit for fingerprinting. Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/993 using your GitHub account
Received on Tuesday, 31 January 2017 18:54:04 UTC