matching VCL to touch screen coordinates

[Ptyl Dragon]

Hi,
We are working on an iOS mobile LibreOffice app.
We got the pan and zoom to follow the pinch and pan gestures, in screen
coordinates, to which we will submit fixes to the lo core - once we solve
this last piece of the puzzle. Apologies for the delay on this. It is
mainly due to logistic issues on our part.

:-|

Well, anyway
It appears, the granularity, or resolution, by which VCL elements are
rendered (such as text for example) is somewhat scaled down from the screen
resolution. for example, when scrolling, the scrolling appear jerky, as
elements "jump" approx 5 - 10 pixels at a time. I have checked to see if
perhaps the scroll command itself is limiting the resolution, but that is
not the case: first, the scrolling is equally jerky regardless of the zoom
level, so it cannot be dependent on the total length of the document or
something like that, and also, when the scroll command was given a delta of
1 pixel, i saw it was transformed to 18 scroll-bar ticks.

In short, it appears, the VCL rendering is the root cause for this jerking,
and i wanted to know if you may have a clue why this is so, and how can we
fix it - so to have the smooth scrolling associated with touch devices.

additionally, we are trying to get the zoom to be continuous, so to follow
a pinch gesture as native touch devices do. currently, i believe zooming is
done in integers, representing percentages. we need to get it to work with
float or double values, so to allow the continuous zooming behavior, common
to touch devices, and we would very much appreciate any help on this:
is this even possible, in terms of - can VCL objects such as text or
images, scale to any size we wish, and if so, what would be the easiest way
to do this.
Also, if this in some way clashes with required behavior of the desktop
version of libre office, we should know, so to add ifndef statements as
required, to allow dual behavior - one for touch - one for desktop - if
necessary.

also, if there is something we need to know and we did not ask, please tell
us (as we are sure there are)

thank you very much in advance

ptyl
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