960209 - Implement B2G bindings for the touch-action property

Status: RESOLVED WONTFIX

(Core :: Panning and Zooming, defect)

Description

[Kartikaya Gupta (email:[e-mail])]

Bug 795567 added some support for the touch-action property and added widget bindings for Metro. We should add widget bindings for B2G as well.

Comment 1

[Nick Lebedev [:nl]]

I would like to volunteer to implement this feature. Kats, could you assign it to me?
Could you also please point me to the files/lines where touch events generation and interaction of b2g widget and apzc happens? I tried to look at widget/gonk folder but didn't find smth relevant.

Comment 2

[Kartikaya Gupta (email:[e-mail])]

Sure. You may find the diagram at [1] useful for navigating the flow of input events on B2G. It's pretty messy.

Touch events on B2G are created in the widget code at [2] and after going through a round of hit detection in the root B2G process, they are dispatched to the APZ code from the call at [3]. Hopefully that should get you started, but please ask more questions if you get at all stuck.

[1] https://bug930939.bugzilla.mozilla.org/attachment.cgi?id=827404
[2] http://mxr.mozilla.org/mozilla-central/source/widget/gonk/nsAppShell.cpp?rev=acdb2a60fdaa#221
[3] http://mxr.mozilla.org/mozilla-central/source/dom/ipc/TabParent.cpp?rev=a1877d97194d#813

Comment 3

[Kartikaya Gupta (email:[e-mail])]

It's probably not worth doing this anymore. A better approach would be to implement bug 1101627 and bug 1101628 which will provide touch-action support in APZ across all platforms without requiring backend-specific work. That's probably about the same (or less) work than doing this, and this is much more subject to rotting as we continue to progress with bug 920036 and bug 930939.