Obj-C Graphing Packages
Certainly one of the nicer graphing packages I've used is the VantagePoint graphing library from Visualize Inc. It's 100% Java, it's fast, well designed, and very feature-complete. Sure, there are a few things I'd like to see them put into the product, but it's very few, and that's impressive. What I've been looking for is an Objective-C/Cocoa version of the same kind of thing so that the code that I'm working on in OS X can have stellar graphing as well. Specifically, right now, I'm looking at the heat/contour graphs in VantagePoint and wishing I had something like that in Obj-C for my Poission's Equation solver code - Potentials.
Potentials is meant to be a very simple solver of Poission's equation in 2D - and as such - be very fast. Once we have the solution in 2D, there's always the time factor which could yield interesting capacitance calculations if that was where we wanted to go, or maybe put in a little fluid and see charge distributed over time. It's something that might be very interesting to play with, but the first step is to be able to see the results in the code without having to run a stand-alone plotting package.
I came across Visual Data Tools, Inc. and their two products DataTank and DataGraph. While DataTank looks to be certainly more than I need, it's also much more expensive, and at $1195 for a license, that's a for a hobby project. And DataGraph looks pretty nice, but is lacking a few of the graph types that VantagePoint has - specifically, the 3D and 3D-mapped-to-2D like the heat and contour graphs. These are the ones that I wanted to use in Potentials, so it's bit of a bind. I wrote the developers to ask if there were these plot types in DataGraph and they mentioned that they were thinking of putting out a new version, targeted somewhere between DataGraph and DataTank, and that the new Bar graph would be in DataGraph soon. While this is good news, I had to write back and ask what the new product would have - I really need the different graph types.
I hope there's something coming that's reasonably priced and has the features I need and integrates well with Xcode. It'd be great to get this code to the next level and have the plotting contained within it. We'll just have to hope that they come back with good news.
UPDATE: it looks like the DataGraph developer is going to keep the low-end product without the two plot types I need for Potentials. I can respect that, but there's no way I can see dropping $1195 for this code... not without some proof that it'll make money, and I don't expect to sell it, so that's especially hard. So I sent an email to the Red Rock Software guys - they make DeltaGraph which has all kinds of nice graphs in it, asking if they had anything that would allow me to incorporate their graphs into my code. I didn't see anything on their site, but it's possible they are thinking about it - or have it. Who knows. It's priced as a nice, graphing package - $300+, but it's not the $1000+ of DataTank. We'll see what they come back with, but I'm not holding out a great deal of hope. I also looked at the VVI Vvidgets and while they seem to have the bases covered, it's more low level, and not nearly as clear-cut as the DataGraph or DeltaGraph tools.