818169 - Add a pref for twiddling with low-res displayport resolution factor

Status: RESOLVED FIXED

(Firefox for Android Graveyard :: Toolbar, defect)

Description

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

BenWa and I were discussing how to reduce memory usage on low-mem devices and he mentioned that we should be able to change the blurriness factor of the low-res displayport and trade off memory usage. We should make this behaviour preffable and then adjust the pref for low-mem platforms.

Comment 1

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

Chris, would you be able to take this bug? (Or if you're swamped, could you point me to what needs to be done so I can work on it?)

Comment 2

[Chris Lord [:cwiiis]]

(In reply to Kartikaya Gupta (:kats) from comment #1)
> Chris, would you be able to take this bug? (Or if you're swamped, could you
> point me to what needs to be done so I can work on it?)

I can do, should only be a small change. How do we want to do this? Currently, the resolution is 0.25 and it extends the displayport 4x in each direction (it doesn't reallocate to the other dimension when hitting page boundaries though). Do we always want to extend 4 times and just alter the resolution? Or do we always want the resolution the same but extend less? Or both?

The resolution should always be a factor of 256 (this isn't a strict requirement, but things will likely look odd when this isn't the case) - I'm of the opinion that 0.25x is the lowest acceptable amount tbh, but I guess we could go to 0.125x.

I guess if we add prefs for both, we can experiment with the numbers.

Comment 3

[Benoit Girard (:BenWa)]

(In reply to Chris Lord [:cwiiis] from comment #2)
> The resolution should always be a factor of 256

Don't you mean a factor of 2?

Comment 4

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

I think I would rather adjust the resolution than the size of the low-res displayport, so that we still have a large enough area that the user doesn't run into checkerboarding. However if we need to reduce memory further then I would look into shrinking the size of the high-res displayport next (bug 792138).

Comment 5

[Chris Lord [:cwiiis]]

Attachment: Add a pref to control the resolution of the low precision buffer

Comment 6

[Chris Lord [:cwiiis]]

Pushed to inbound: https://hg.mozilla.org/integration/mozilla-inbound/rev/dbb56727c829

Comment 7

[Ed Morley [:emorley]]

https://hg.mozilla.org/mozilla-central/rev/dbb56727c829