I have filed https://bugzilla.mozilla.org/show_bug.cgi?id=878029 w/ patch for this.
On Mon, May 27, 2013 at 5:53 PM, Tim Chien <[email protected]> wrote: > Hi all, > > As :roc suggests this is a product issue, rather a technical issue, I > would like to bring this topic to dev-b2g so that we could agree what > to do about it. > > So, every screen of every device comes with it's density. > GetDefaultScaleInternal() is responsible to translate the raw dpi > value and determine the correct device-pixel-ratio; i.e. device pixels > per CSS pixel. > > A month ago, :mwu landed a patch [1] (thanks!) that basically do this: > > < 239dpi : 1x > < 337dpi : 1.5x >>= 337dpi : 2x > > I wasn't realize the math were off until recently; after checking with > AOSP doc [2], I found that AOSP did not specify a hard dpi range for > each ratio, but give mean values: > > ~120dpi (ldpi) : 0.75x > ~160dpi (mdpi) : 1x > ~240dpi (hdpi) : 1.5x > ~320dpi (xhdpi): 2x > > The problem is quite obvious if you compare the tables: ignoring ldpi > screens, our calculation puts half of the Android hdpi (1.5x) devices > out there as ratio=1x, and most of the xhdpi (2x) devices as > ratio=1.5x. > > I would imagine this could result a lot of surprises to our hardware > partners; with the same BSP, we somehow downgrade or upgrade their > devices and make the UI too small (or too big)[3]. > > I propose we fix this by amend the calculations to: > > < 200dpi : 1x > < 280dpi : 1.5x >>= 280dpi : 2x > > If this sounds alright, I will file a bug and submit a patch. Thanks. > > > [1] https://bugzilla.mozilla.org/show_bug.cgi?id=845182 > [2] See > https://developer.android.com/guide/practices/screens_support.html#NewQualifiers > on definition and > https://developer.android.com/guide/practices/screens_support.html#DesigningResources > on pixel ratio > [3] You might not know it because Gaia comes with it's own > |responsive.css| fix to resize the UIs -- which is the wrong approach > and is due to be removed. > > -- > Tim Guan-tin Chien, Engineering Manager and Front-end Lead, Firefox > OS, Mozilla Corp. (Taiwan) > _______________________________________________ > dev-b2g mailing list > [email protected] > https://lists.mozilla.org/listinfo/dev-b2g -- Tim Guan-tin Chien, Engineering Manager and Front-end Lead, Firefox OS, Mozilla Corp. (Taiwan) _______________________________________________ dev-b2g mailing list [email protected] https://lists.mozilla.org/listinfo/dev-b2g
