The code was wrong, because it deleted the ChartItems in the
main UI thread, not the render thread. This would delete the
QSG nodes in the UI thread and then crash on mobile.
Therefore refactor this part of the code by adding the
items to be deleted to a list that will be deleted by the
render thread.
As a drop in replacement of std::unique_ptr, implement
a silly ChartItemPtr class, which auto-initializes to null.
This turns the deterministic and easily controlled memory
management into a steaming pile of insanity. Obviously,
this can be made much more elegant, but this has to do for now.
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
Turn the background grid into QSGNodes. Each grid line is
represented by a QSG line item. An alternative would be
drawing the grid into a QImage and blasting that onto the
screen. It is unclear which one is preferred.
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
Android and iOS use qmake, so add the code to the .pro file.
This also removes all remnants of QCharts includes and uses and all the
references to QCharts in our various build systems.
That was a brief but extremely useful detour.
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
It turns out that the wrong base class was used for the chart.
QQuickWidget can only be used on desktop, not in a mobile UI.
Therefore, turn this into a QQuickItem and move the container
QQuickWidget into desktop-only code.
Currently, this code is insane: The chart is rendered onto a
QGraphicsScene (as it was before), which is then rendered into
a QImage, which is transformed into a QSGTexture, which is then
projected onto the device. This is performed on every mouse
move event, since these events in general change the position
of the info-box.
The plan is to slowly convert elements such as the info-box into
QQuickItems. Browsing the QtQuick documentation, this will
not be much fun.
Also note that the rendering currently tears, flickers and has
antialiasing artifacts, most likely owing to integer (QImage)
to floating point (QGraphicsScene, QQuickItem) conversion
problems. The data flow is
QGraphicsScene (float) -> QImage (int) -> QQuickItem (float).
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
