Commit graph

10 commits

Author SHA1 Message Date
Dirk Hohndel
b40354c7f2 build-system: compile stats code on mobile OSs
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>
2021-01-10 15:16:52 -08:00
Berthold Stoeger
e7907c494f statistics: convert chart to QQuickItem
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>
2021-01-10 15:16:52 -08:00
Berthold Stoeger
b5c8d0dbb4 statistics: fix range in categorical axes
The range for a one-bin chart is [-0.5,0.5], thus the range
in an n-bin chart is [-0.5,n-0.5], not [-0.5,n+0.5].

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
2021-01-09 14:25:02 -08:00
Berthold Stoeger
2a850025b2 statistics: add ticks at beginning and end of the axis
The grid is based on the axis ticks. If labels in histogram
axes were skipped (because there are too many bins), it could
happen that the grid was incomplete, because the first and/or
last tick were missing. Add these explicitly.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
2021-01-07 10:39:52 -08:00
Berthold Stoeger
405e6b6b69 statistics: fix chart features: regression line and median/mean
The coordinates of these were calculated when creating the feature.
This is wrong, because the min/max values of the axes can change
on resize to get "nice" number. Therefore, recalculate after resizing.
This means that the general "LineMarker" class has to be split into
two classes, one for regression lines and one for median/mean
markers.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
2021-01-06 12:31:22 -08:00
Berthold Stoeger
ab324ed769 statistics: paint custom grid
With removal of QtCharts' axes, the grid was lost. Readd it.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
2021-01-06 12:31:22 -08:00
Berthold Stoeger
8dfa3f6db3 statistics: draw title of axes
Easy enough to implement, but one weirdness:
To get the height of the rotated text, one has to access the
width() member of the boundingRect. I'm not sure if that makes
sense, but so be it.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
2021-01-06 12:31:22 -08:00
Berthold Stoeger
4ab9f1c6b0 statistics: replace QtCharts' axes
Replace by custom implementation, with the ultimate goal to
remove the QtCharts module. This doesn't yet display axis
titles or a grid.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2021-01-06 12:31:22 -08:00
Berthold Stoeger
23d781deba statistics: save chart in axis class
The chart was passed as argument to the function recalculating
the axis labels. Instead, pass the chart in the constructor of
the axes and save it. This gains us flexibility for the future:
There will be more functions that need to access the chart (e.g.
resizing of the axes).

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
2021-01-06 12:31:22 -08:00
Berthold Stoeger
31da037701 statistics: implement axes
Implement five kinds of axes:
 - ValueAxis: a standard axis for plotting numerical linear data.
 - CountAxis: a ValueAxis for plotting counts of dives.
 - CategoryAxis: an axis for plotting discrete variables without
   any notion of distance.
 - HistogramAxis: an axis for plotting bins with a numeric value.
 - DateAxis: a HistogramAxis that formats dates.

The axes derive from a common virtual base class that defines
a small interface, notably, returning the minimum and maximum
displayed value and redrawing the axis.

The mapping and painting is performed by QtCharts' axes. On
the one hand, using QtCharts turned out to be too inflexible.
On the other hand it allowed us to quickly prototype the charts.
Ultimately, we should do our own drawing of the axis.

As a testament to the inflexibility, QtCharts' axes do not
allow for repeated labels is needed for quarter-based date
charts (year, Q2, Q3, Q4, year, Q2, Q3, ...). Therefore the
code disambiguates labels by adding unicode zero-width spaces.
Wonderful.

When omitting labels due to space reasons, the histogram
axis attempts to show "preferred" labels. In the quarter
example above, it tries to show full years.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
2021-01-02 11:04:03 -08:00