1324307 - Ensure that -moz-device-pixel-ratio behavior matches -webkit-device-pixel-ratio

Status: RESOLVED WORKSFORME

(Core :: CSS Parsing and Computation, defect, P3)

Description

[Thomas Wisniewski]

As per recent CSSWG discussion[1],

>- Apple is considering changing webkit's behavior to align with the spec and other implementations,
>and make page zoom affect resolution. If they decide against in, they should file a bug against the spec.
> 
>- If Apple changes their implementation of resolution as discussed in the previous point, they are
>unsure whether to keep -webkit-device-pixel-ratio a strict alias of resolution, or have it preserve
>the historical behavior, but lean towards the later one. If they decide that these should not be
>strict aliases, they should file a bug against the spec, which defines them to be.

Since we now alias -moz-device-pixel-ratio as -webkit-device-pixel-ratio (as of v45 for the WhatWG Compatibility Standard), we should ensure that it matches whatever behavior WebKit goes with.

[1] https://github.com/w3c/csswg-drafts/issues/417

Comment 1

[Firefox Bug Husbandry Bot]

Migrating Webcompat whiteboard priorities to project flags. See bug 1547409.

Comment 2

[Firefox Bug Husbandry Bot]

See bug 1547409. Migrating whiteboard priority tags to program flags.

Comment 3

[Emilio Cobos Álvarez (:emilio)]

They evaluate using the same exact function: https://searchfox.org/mozilla-central/rev/763b888847ac7291248b62ef3ab99da6ba2332d6/servo/components/style/gecko/media_features.rs#732-752