850692 - consider adjusting default scaling on larger hidpi screens

Status: RESOLVED INVALID

(Core Graveyard :: Widget: WinRT, defect)

Description

[Jonathan Kew [:jfkthame]]

This is a followup to bug 816709. The patch there aims to make our scaling (the ratio of CSS pixels to actual device pixels) respect the ResolutionScale factor from Windows::Graphics::Display, which will give us 100%, 140% or 180% scaling depending on the display's size and resolution, and whether the Ease of Access option to "Make everything bigger" has been turned on.

However, I've observed that on my 13" ultrabook, where ResolutionScale defaults to 100% (which accords with the documentation that suggests it would scale up content for screens of less than 12.5", IIRC), the actual behavior of IE in Metro mode is more complex.

In particular, on this machine, when ResolutionScale is 100%, IE/Metro appears to be following the -Desktop- Windows environment's preference for "text size" (the 100%/125%/150% or Custom options in the Display control panel). So with my Desktop environment set to "Medium" (125%) or "Larger" (150%) scaling, IE/Metro also defaults to a 125% or 150% view, even though ResolutionScale is 100%.

Then, if I use the Metro Ease of Access setting to bump ResolutionScale up to the next value, IE/Metro's view does -not- scale by a corresponding amount; in all cases, it ends up at about 175%, regardless of what the original scale was. So with the desktop env set to "Normal", the "Make everything bigger" option has a HUGE effect, while if the desktop env is set to "Larger", it makes relatively little further difference.

It's not clear to me exactly what the optimal combination of these factors will be, but I do think we probably want to make FF/Metro's default scaling take some account of the resolution chosen in the desktop environment, similarly to what IE10 seems to be doing.

Comment 1

[BMO Automation]

This component is no longer valid. Closing bug as INVALID.