Bug 79487 – Background-position doesn't transition when using different units for each state

• Component: CSS
• Status: RESOLVED CONFIGURATION CHANGED

[Thijs Reijgersberg]

When setting the background position in one unit and on :hover on a different unit webkit doesn't transition the background-position change. 

See http://dabblet.com/gist/1900938 for a test case.

The colour transitions properly but the background position jumps from one state to the next. 
When declaring both background position declarations in the same unit webkit does transition the background position properly.

[Shane Stephens]

It's not currently possible to transition between unit types (here you're transitioning between a percentage and a length). Although this limitation isn't explicit in the specification (http://www.w3.org/TR/css3-transitions/) it is implied.

Note that the CSSWG is currently considering whether and how to handle transitions between unit types. For now I've marked this bug as an enhancement request.

Is there some news about this? I am experimenting the same issues. Every other browsers are able to transition this properly.

[Ahmad Saleem]

We don't have wayback archive copy for this - this is only link:

https://web.archive.org/web/20140808022946/https://dabblet.com/gist/1900938

and it seems to not load properly.

I am not sure if we have fixed this bug or not or this exist or not but nothing more can be done without test case.

@Karl & @Antoine - Any input or we should mark this as 'RESOLVED CONFIGURATION CHANGED'?

[Antoine Quint]

Created attachment 471461 [details]
Test

Attaching an example that animates "background-position" between a length and a percentage and checking that it triggers a transition.

[Antoine Quint]

The attached example triggers a transition in all browsers I've tested. I think we can close this.