Hey Charles, 2009/11/3 Hubbard, Charles W <[email protected]>: > Recently I've been working with the WCartesianChart widget to graph data > sets (as some of you may recall from my recent earlier posts). As > things stand now, I've got a WCartesianChart solution that is working > well. I would like the ability to zoom in on a portion of the plot > data, and, for that, I am having some difficulty. > > I debated whether or not I should post this as two separate posts, but > finally decided to do it all in one, because my two issues are related. > First, I'll tell you what I'd like to do and then what I'm currently > trying to do, but seem to have some buggy behavior. > > 1) To zoom in on a section of the chart data, what I'd really like to be > able to do is drag a bounding box around the area of interest with the > mouse and then have the chart widget automatically replot with the axes > adjusted to just display the data that fell within the region of the > bounding box. Naturally, there would also need to be some way to undo > the "zoom" and get back to the original plot limits. I have no idea how > to do this. I don't even know if it is possible. It's not supported by > the current WCartesianChart widget. If it is possible and doesn't > involve an enormous amount of overhead, I wonder if the developers would > consider implementing such a feature in some future version of the > library.
This would be not too hard, and indeed quite useful. However, I believe it would immediately prompt for a next feature: to be able to navigate also by dragging the charting area (correct me if I'm wrong?). That feature is a lot harder if you want to be clever enough to only render the part of the chart that is visible (or nearby). Ideally, I would therefore implement these changes together. But, see also your new post... > 2) Okay, so much for the feature request. Here's what I am actually > doing now. For my current application, It's acceptable to leave the I guess this has been refined already a bit since, as explained in your newer post ? > Y-axis scaled the way it is and only zoom in on a portion of the X-axis. > As a test, I set up two WLineEdit widgets into which I can manually > enter the minimum and maximum X-axis values I'd like to see plotted, and > then I call the X-axis (WAxis) setRange() method to limit the range of > the X-axis data to those values. That *almost* works fine, but I am > seeing some odd behavior that might be a bug. In my full dataset, I > have maybe 10 series to plot, and I can select which ones to plot and > which ones not to plot using WCheckBox widgets. If I select three > series (for example), then the first two plot perfectly, with the left > and right edges of the series data being properly clipped at the X-axis > boundaries previously set with setRange(). However, the third series > doesn't get clipped at the axis boundaries. Instead, it clips further > to the left and right, at what appears to be the boundary of the entire > WCartesianChart widget (that is, the series starts on the far left over > the top of the Y-axis label and ends on the far right over the top of > the chart legend). If I then add a 4th series to the mix, the three > original series now clip perfectly, and only the 4th series clips to the > edges of the WCartesianChart rather than the edges of the X-axis. This > behavior is consistent in that all series selected always clip exactly > right except for the very last series, which always clips long. Any > ideas? That seems like a real bug indeed. To narrow down whether this a bug in the charting library, the painter, or a specific rendering backend, do you have the same behavior using different renderers (for example using VML on IE and using Canvas/SVG on Firefox ?) ? Regards, koen ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july _______________________________________________ witty-interest mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/witty-interest
