[css-device-adapt] Remove support for device-width, device-height

There have been experimentation with enabling viewport meta for all  
products in Blink and I was brought into the discussion.

Device-width and device-height works when the browser window uses the  
whole screen and isn't resizable. When you start to support @viewport (or  
viewport meta) in browsers where the window is smaller than the screen,  
you'll get undesireable results. The question is if there is really a need  
for device-width/device-height at all since the author would normally mean  
"@viewport { width: auto; height: auto; }" instead.

The viewport meta background is that Safari and Presto, at least, have  
been truly using device-width and device-height as what they are: width  
and height of the device in CSS px. It's detectable for device-height as  
content="initial-scale=1" will give you an ICB height that subtracts the  
height of the UI chrome from the device-height, while  
content="height=device-height" will give you the height of the screen in  
CSS px regardless of the presence of UI chrome. Now, the current  
implementation in Blink will actually translate device-width/height to the  
width/height of the ICB established by the browser window showing no  
difference between content="initial-scale=1" and content="height".

An important argument in favor of removing the support for the device-*  
values in @viewport is that authors would likely continue to use those  
values as they match what they're used to from viewport meta, which would  
be bad.

PROPOSAL: Remove device-width and device-height from <viewport-length> and  
keep them in the viewport meta part.

-- 
Rune Lillesveen

Received on Wednesday, 29 May 2013 08:22:32 UTC