987472 - Setting TranslateX while Homescreen Pans Can be Optimized

Status: RESOLVED WONTFIX

(Firefox OS Graveyard :: Gaia::Homescreen, defect, P2)

Description

[Mason Chang [Inactive] [:mchang]]

Currently, the homescreen app sets the translateX on every frame with "translateX" + pixelTranslate + "px", which creates a new string concatenation, string allocation, string flatten, and a GC cleanup later. While it's not an overbearing burden, this can be optimized. We need some support from layout to set simple CSS transforms w/o doing the stringify, concat, and parsing on the CSS side, which should buy us some performance gains.

Comment 1

[Kevin Grandon :kgrandon]

I think we need to figure out what the goal is here. I don't think creating new object primitives is going to fly, but I do think there might be some ways to have a fast path for CSS transforms and hardware accelerated properties.

My suggestion is to file a platform bug to add support for fast paths for hardware accelerated properties, then block on that bug. Things like scale(), translateX(), translateY(), and translateZ(), etc.

Comment 2

[Kevin Grandon :kgrandon]

I filed bug 987477 as a general bug for investigating a solution for CSS transforms. There may already be something filed somewhere though.

Comment 3

[Kevin Grandon :kgrandon]

We need either bug 987477 or bug 987479 to solve this. This is also needed for the new homescreen effort.

Comment 4

[Mason Chang [Inactive] [:mchang]]

Just spoke with Kevin, this isn't a blocker on the vertical homescreen at the moment. Since we now scroll with APZ, we only set transforms while in homescreen edit mode. It's a very nice to have feature though.

Comment 5

[Mason Chang [Inactive] [:mchang]]

Since we have the vertical homescreen, we don't need this while panning the homescreen.