688812 - Figure out when to use 16 bit vs 24 bit colour on mobile

Status: NEW

(Core :: Graphics, defect)

Description

[Joe Drew (not getting mail)]

Right now, we almost always use 16-bit colour on mobile (except when we need an alpha channel, when we use 32-bit). However, some mobile devices actually have 24-bit displays now, e.g. the Samsung Galaxy S II. We should find a way to detect what type of display a device has, and use the appropriate colour depth on that device.

Comment 1

[Sean Martell]

+1 to this!

Want to share an example of one of our upcoming designs that is being limited by 16-bit colour - http://cl.ly/image/2a0l2q17473h/o

The banding on the globe is CSS box-shadow and gradients. I had to remove the page background gradient entirely as the banding was too pronounced.

Would love to see us explore the higher depths if the device supports it. 

Thanks!

Comment 2

[Matt Brubeck (:mbrubeck)]

On Android we now use 24-bit color on devices with at least 768MB of RAM.

Is there any work left to do for this bug (for non-Android mobile platforms, e.g. Firefox OS) or should we close it as a duplicate?

Comment 3

[microrffr]

Would you consider making this configurable? Some of the other features gated by device memory also have prefs that can override it.

Comment 4

[Milan Sreckovic [:milan] (needinfo for best results)]

(In reply to microrffr from comment #3)
> Would you consider making this configurable? Some of the other features
> gated by device memory also have prefs that can override it.

On Android, gfx.android.rgb16.force will force 16-bit color on 24-bit devices.  Doesn't really make sense to try the other way around.  Does that work for you?

Comment 5

[microrffr]

(In reply to Milan Sreckovic [:milan] from comment #4)
> On Android, gfx.android.rgb16.force will force 16-bit color on 24-bit
> devices.  Doesn't really make sense to try the other way around.  Does that
> work for you?

Why doesn't it make sense to try the other way around?

Comment 6

[microrffr]

(In reply to microrffr from comment #5)
> Why doesn't it make sense to try the other way around?

Oh, duh. Of course.

I wanted to enable 24-bit color on a 24-bit device with low memory.

Comment 7

[Milan Sreckovic [:milan] (needinfo for best results)]

Ah, yes, I can see wanting to try what things will look like, and only having the low memory device handy.  So, you're right, no preference currently, but I see how it would be useful. To get it, I would file a new bug; either to force 24-bit on devices that support it, regardless of the current memory, or perhaps to set the memory limit at which we allow 24-bit.  So, if you set that to 0, it amounts to the "force 24-bit", but perhaps it is a more appropriate pref to have.