hi koen, that's a little bit more information than i needed ;)
would it be wise to make a subclass from WCartesianChart (say WVirtualCartesianChart) and put all the things you described (WPaintedWidget, chartArea(), JavaScript) into this class. or inherit from WAbstractChart and make calculating, drawing and rendering in a completely different way than it is done in WCartesianChart? an other thing is that WAbstractItemModel which is used for rendering the chart has to be newly calculated and replaced after every scrolling in the case you have a lot of data which can not be hold by the model at one time. therefore the chart has to manipulate the model on itself. is that wise/possible? thanx, johannes. > Hey Johannes, > > 2010/1/26 Johannes Kepler <[email protected]>: > > i'm using continuous data for rendering a WCartesianChart which is > > working very well. > > now i was wondering if it would be possible to render that chart in that > > way that you can scroll through data just in time by clicking and draging > > with the mouse, similar to the mandelbrot WVirtualImage example. > > > > the thing is, my data is going on through month and years, so if i want > > to see a larger interval i have to give the time interval which is > > rendered every time anew. that's not really comfortable. > > We have had this feature request before, and the concept is obviously > totally likable. > Unfortunately, I didn't have it in mind when designing the charts. I > think the biggest hurdle is that you want to render the different > parts of the chart as different WPaintedWidget's: > > - the contents > - the axes (and legend) > > When a user drags the contents (dx, dy), both axes can then be dragged > along but only using the corresponding coordinate (dx or dy). When the > user releases the drag, you can trigger the backend to update the > rendered view. > > So it needs a bit of work to fit it in the current WCartesianChart design: > - make WCartesianChart a composite which contains (3 ?) WPaintedWidget's > - move the chartArea() calculations from the renderer into cartesian > chart which uses this to layout the painted > widgets > - call the relevant parts of the renderer on relevant parts of the axes > - copy some the JavaScript over from WVirtualImage to implement the > client-side dragging > - (optionally, optimize rendering so that you only render currently > visible things) > > That is already a decent sized feature request ticket, but it is > obviously also a fun one. > > > does someone have an idea? > > My idea is that someone should get really enthousiastic about this and > do the work :-) > > Regards, > koen > > --------------------------------------------------------------------------- > --- The Planet: dedicated and managed hosting, cloud storage, colocation > Stay online with enterprise data centers and the best network in the > business Choose flexible plans and management services without long-term > contracts Personal 24x7 support from experience hosting pros just a phone > call away. http://p.sf.net/sfu/theplanet-com > _______________________________________________ > witty-interest mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/witty-interest > ------------------------------------------------------------------------------ The Planet: dedicated and managed hosting, cloud storage, colocation Stay online with enterprise data centers and the best network in the business Choose flexible plans and management services without long-term contracts Personal 24x7 support from experience hosting pros just a phone call away. http://p.sf.net/sfu/theplanet-com _______________________________________________ witty-interest mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/witty-interest
