QML charts api

2beers

Hi everyone. I'm interested if someone is working on a qml charts api. I'm asking because I might help him. If not I will start working on one.

geronik

I am also interested in qml charts api. One thing I haven't done it clear is whether it is worthy to invest time in extending qml elements with C++.
The current paint model in qml is based on QGraphicsView, which may replaced by the graphscene in the future. The question is if this is true, then what's gonna happen to previously extended-user-custom qml elements?

2beers

it's a good question geronik. hope we get some official response, cause I wouldn't want to work and then to be forced to start over

lynardo

Hi there,

there is a way to make charts with the QML Canvas modul ("link":http://qt.gitorious.org/qt-labs/qmlcanvas), but its not the easiest way. So a charts api would be really nice!

Much luck, if you wanna do that

lynardo

andre

Wouldn't it make sense to wrap an existing qt charts library for use with QML? No need to re-do the actual chart rendering, is there?

2beers

yea. but I was thinking to make it with some animated transitions and some eye-candy :D

[quote author="Andre" date="1297613877"]Wouldn't it make sense to wrap an existing qt charts library for use with QML? No need to re-do the actual chart rendering, is there?[/quote]

andre

OK, best of luck then!

mbrasser

[quote author="geronik" date="1297322779"]The current paint model in qml is based on QGraphicsView, which may replaced by the graphscene in the future. The question is if this is true, then what's gonna happen to previously extended-user-custom qml elements?[/quote]

You'll almost certainly need to port them. We'll try to make porting a QDeclarativeItem subclass to the scene graph as painless as possible (for example, we might try to offer an item that allows QPainter-based painting, which is cached to a pixmap). For something with lots of drawing (like graphing), it may be to your advantage to rewrite those bits when the time comes, to take advantage of the performance boosts that scenegraph should provide.

Regards,
Michael

jimknopf

hi 2beers,
have you made any progress in writing a QML charting component? I'd be interested in seeing this happen and would be happy to help...

2beers

I postponed my project until qml scene graph is released.

[quote author="jimknopf" date="1298803401"]hi 2beers,
have you made any progress in writing a QML charting component? I'd be interested in seeing this happen and would be happy to help... [/quote]

geronik

Waiting for scene graph.. and how long is that? Scene graph porting could be not such a difficult task, and I suppose Trolls will do it quite easy for us. I am in for the graph charts api..

2beers

don't know how long it will take until scene graph is ready, but you are free to start the charts project

[quote author="geronik" date="1299158941"]Waiting for scene graph.. and how long is that? Scene graph porting could be not such a difficult task, and I suppose Trolls will do it quite easy for us. I am in for the graph charts api..[/quote]

ZapB

I have a reasonable Qt Charting component already and I am looking at adding QML support to it soon. See this "thread":http://developer.qt.nokia.com/forums/viewthread/4209/

geronik

[quote author="ZapB" date="1299169271"]I have a reasonable Qt Charting component already and I am looking at adding QML support to it soon. See this "thread":http://developer.qt.nokia.com/forums/viewthread/4209/[/quote]

Very nice job, it really looks great..

ZapB

[quote author="geronik" date="1299228355"]
Very nice job, it really looks great..
[/quote]

Thank you. Is there anything missing from what I have shown that would be useful to you in a charting component?

I am still thinking about how to add various levels of interactivity to the plots.