Most colors were already collected there, but a few were dispersed
throughout the source files.
For future themeability, move the remaining colors to this common
place.
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
The position of the legend was reset when resizing. This was
OK as long as the legend wasn't movable.
To avoid resetting the position, store the center position
of the legend relatively to the size of the canvas. On
resize restore the center to the same relative size.
To avoid code duplication, move the sanitizing of the
coordinates from the StatsView to the Legend.
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
The chart items were drawn in order of creation. To control this,
add a notion of Z-value. In contrast to QGraphicsScene, make
this a small integer value.
To controll order of drawing, a plain QSGNode is created for
every possible Z-Value and items are added to these nodes.
Thus, items are rendered by Z-value and if the Z-value is equal
by order of creation.
Likewise split the list of chart-items into Z-values, so that
items can be quickly unregistered: The items that will be
removed individually will usuall be part of Z-levels with only
few items (e.g. legend, infobox). Z-levels with many items
(notably the series) will always be fully rebuilt.
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
In order not to waste CPU by constantly rerendering the chart,
we must use these weird OpenGL QSGNode things. The interface
is appallingly low-level and unfriendly.
As a first test, try to convert the legend. Create a wrapper
class that represents a rectangular item with a texture
and that will certainly need some (lots of) optimization.
Make sure that all low-level QSG-objects are only accessed
in the rendering thread. This means that the wrapper has
to maintain a notion of "dirtiness" of the state. I.e.
which part of the QSG-objects have to be modified.
From the low-level wrapper derive a class that draws a rounded
rectangle for every resize. The child class of that must then
paint on the rectangle after every resize.
That looks all not very fortunate, but it displays a
legend and will make it possible to move the legend
without and drawing operations, only shifting around
an OpenGL surface.
The render thread goes through all chart-items and
rerenders them if dirty. Currently, on deletion
of these items, this list is not reset. I.e. currently
it is not supported to remove individual items.
Only the full scene can be cleared!
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
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>
Dirk says rounded corners look better. This now looks a bit
extreme to me and probably the border size should be increased.
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
After each column, instead of setting the new x-variable, the
new value was added to the old value. This led to ever increasing
gaps.
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
Two warnings concerning division by zero and non-initialization
of a member variable, respectively.
Both are false positives. However, Coverity is excused because
it probably doesn't understand std::vector<> and also can't
know whether the object in question is generated in a different
source file.
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
z-values determine the order in which objects on the chart are
painted. To reduce chaos, collect all z-values in a header file.
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
For some chart (e.g. pie charts or stacked bar charts), we want
to display a legend. QtCharts' legend interface happens to be
private and therefore is of no use.
This introduces a legend box which is implemented using
QGraphicItems, which can be placed on top of QCharts. It's very
unfancy, but works for now. If there are too many items, not
all are shown. Currently, the legend is configured to fill
at most half of the width and half of the height of the chart.
This might need some optimization.
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
