These values were used for items on the QGraphicsScene and
have been replaced by integer values used on the QSG scene.
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>
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>
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>
