On 10-02-16 15:28, Sebastian Kügler wrote:
On Wednesday, February 10, 2016 03:24:38 PM Jan Mulder wrote:
As has been noticed by a number of people that are active in the android
mobile development, the scrolling/swiping from dive-detail to
dive-detail is not "smooth". It stops and moves forward at (lets say)
80% of the width of the profile window, and up to now it is unclear if
it is a QML/Qt thing or something in our code.
This is most likely the profile being rendered, which is quite slow. Ideas to
make it faster:
- cache the dive profiles, so only render them one for a given size, re-read
from disk; this would of course only help after a dive has been shown at
least once
- use an imageprovider *1 for the dive profile; this allows to load them
asynchronous, could be combined with the above cache idea
*1 http://doc.qt.io/qt-5/qquickimageprovider.html
Tempted by the hypothesis of the slow profile rendering being the the
issue of the "strange scrolling behavior", I did the following
experiment. Commented the entire QMLProfile block (and the references to
it) from the DiveDetails.qml. This does result in a page without the
profile, so, with knowing much about the internals of QML, I assume that
this suppresses any dive profile rendering related computations.
This does not change the strange scrolling behavior.
I agree that the profile rendering is an computational serious effort,
and that asynchronous computation, and caching are very relevant ideas
to tackle this, but I doubt that it touches the "80% scrolling" behavior.
best,
--jan
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