On 19/11/14 09:55, Morten Johan Sørvig wrote:
> Meeting summary:
>
> * Qt Quick will operate in device pixels and get one or more “device
> independent” units (pt, cm, mm, inches, …)
After chatting with the involved parties, this is a bit more detailed
breakdown:
QtQuick, from an API pow (Item { width: 500}) will continue to work in
logical pixels. Logical, because on at least two platforms (iOS and OSX)
the pixel is not a physical device pixel. On other platforms the logical
pixel is typically the same as a device/physical pixel, partly because
the platform doesn't have a concept of devicePixelRatio (yet), and
partly because we haven't implemented support for it in the platform
plugin, for platforms where it exists. The latter needs to be fixed by us.
There will be a way to override the device-pixel-ratio on an application
global level, typically by setting it to 1, in case you want to
explicitly work in device/physical pixels throughout your app. This will
influence the entire Qt coordinate system, eg. mouse events, etc, just
like device-pixel-ratio does today. This is typically not what you would
do for a cross-platform app, as you would have to deal with density
differences between platforms yourself.
Work will have to be done on asset management in Qt to make it easier to
support assets with multiple density levels in a cross-platform manner.
There may be introduced units in Quick that refer to an explicit pixel
reference, eg 'px' for an explicit device/physical pixel, and 'dp' for a
density-independent (logical) pixel (these are the names used on
Android, just as a reference). This topic is still undecided.
tor arne
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