916904 - add image visibility prefs for metro

Status: RESOLVED FIXED

(Firefox for Metro Graveyard :: General, defect)

Description

[Timothy Nikkel (:tnikkel)]

See bug 915526 comment 10.

Comment 1

[Timothy Nikkel (:tnikkel)]

So since I failed to override the image visibility prefs for metro that means image visibility has been turned on for metro, even when it didn't really work right.

Would you like metro to be the guinea pig that has image visibility enabled first in a non-traditional desktop Firefox setting? Since it's already been turned on in a somewhat broken state there seems like little downside to leaving it on now that it should be in a working state.

Comment 2

[Jim Mathies [:jimm]]

What kind of side effects are we looking for? Looks like metrofx currently gets layout.imagevisibility.enabled set to true in all.js. So if we keep that would it mean we wouldn't need the additional prefs in bug 915526?

Comment 3

[Timothy Nikkel (:tnikkel)]

(In reply to Jim Mathies [:jimm] from comment #2)
> What kind of side effects are we looking for? Looks like metrofx currently
> gets layout.imagevisibility.enabled set to true in all.js. So if we keep
> that would it mean we wouldn't need the additional prefs in bug 915526?

Yeah, if we leave layout.imagevisibility.enabled undefined it will be true. I would like to set layout.imagevisibility.numscrollportwidths to 1 though (because with a pan and zoom browser we do a lot more horizontal panning than in a regular desktop browser), and that is not the default value.

If everything is working as expected the only side effects would be more memory used to keep around decoded images that are to the left/right of the screen, and correspondingly less image decode lag for those images as they come into view.

Comment 4

[Timothy Nikkel (:tnikkel)]

Attachment: patch

I defined all the prefs, even the ones that have the same as the default value here.

Comment 5

[Jim Mathies [:jimm]]

Comment on attachment 805470 [details] [diff] [review]
patch

Please add a comment explaining what layout.imagevisibility is.

Comment 6

[Timothy Nikkel (:tnikkel)]

I added

+// image visibility prefs.
+// image visibility tries to only keep images near the viewport decoded instead
+// of keeping all images decoded.

Comment 7

[Timothy Nikkel (:tnikkel)]

https://hg.mozilla.org/integration/mozilla-inbound/rev/40276572c2a1

Comment 8

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/40276572c2a1