Qt Charting Component - Feedback request
hi, really nice plots !
Do you use QGraphicsPathItems for the “line” plots? And the points symbols?
Almost. I have written my own custom QGraphicsItem subclasses. In this case the lines are drawn by a ZSplinePathItem and the points are drawn by ZPointItem. Both these classes inherit from another class of mine called ZTransformedPlotItem which allows the subclasses to easily perform transformations between the natural plot coordinate system and the usual QGraphicsView parent item coordinate system. The idea being that by replacing the coordinate system in use you can change the plot type ie switch to a polar coordinate system.
The ZSplinePathItem uses a QPainterPath internally.
the look and feel seems to be really well defined, yes I’d like to play with !
Thank you again. I have a little more work left to do before I will make a first release but I am slowly getting there. Things left to do include:
- Contour plots (these are almost done)
- Bar/column charts
- More style abstractions for easier customisation
- Peformance optimisations
- Lots more testing ;-)
I’ll post back here as I make progress.
Woohoo! I’ve just managed to get the basic plot example (shown above running in the simulator) to run natively on Symbian^3. This feels like a major step for me and it shows that we can now relatively easily create applications containing charts on desktop, embedded and mobile targets. :D
The only changes I made compared to the same example built for desktop was to make the font size a little smaller to make better use of the available space and to call QWidget::showFullScreen() rather than QWidget::show() on the QGraphicsView. I’ll try to factor the font size adjustments into the library. The choice between show() and showFullScreen() is down to the application writer.
Charttypes that I miss in your list are the financial stock charts like bar charts (open, high, low, close) and candlestick charts. I know that many developers are looking for something like that. I am using qwt for that purpose but it does not support these types either.
It would be great to have these as well.
How can I use your widget from within QML?
Can I draw xy science plots using data from a C++ class (say a std::vector) ?
In my app, the data may arrive any time, so how can I notify the plot widget to draw the new data?
Is there an example ?
Thank you for the great work. It seems what a lot of people have been waiting for!