Due to the current gap in continued funding from the U.S. National Science Foundation (NSF), the NSF Unidata Program Center has temporarily paused most operations. See NSF Unidata Pause in Most Operations for details.
Due to the current gap in continued funding from the U.S. National Science Foundation (NSF), the NSF Unidata Program Center has temporarily paused most operations. See NSF Unidata Pause in Most Operations for details.
Hi Bill- Thanks for the suggestion. Bill Hibbard wrote:
Strange your original message never appeared on the list. What you generally need is a way to find the closest point on a 1-D manifold to a ray (the ray defined by the cursor). There are two similar things in the system: 1. DataRenderer.findRayManifoldIntersection() uses Newton's method to find the intersection of a ray with a 2-D manifold. 2. DataRenderer.java, lines 2140-2155 finds the closest point on a 1-D line (a straight 1-D manifold) to a ray. If I were you, I'd start with a simple approach and add complexity only as needed. So I'd start with a manipulable point initialized somewhere on your 1-D manifold, linked to your Display via a DirectManipulationRendererJ3D. As the user drags this point, it will move in a plane parallel to the screen but not be constrained to move along your 1-D manifold. In fact, such constraint is impossible given that in general the ray defined by the user's cursor location will not intersect the 1-D manifold. So render the manipulable point as just a single dim point. But also display a more prominent point that moves along the 1-D manifold, at the sample along the manifold that your CellImpl (triggered by changes in the manipulable point) calculates to be the nearest point on the 1-D maniold to the manipulable point.
This is a good suggestion. The only downside would be having the manipulable point visible. It might be better to have some display listener listen for clicks and do the screen transforms below.
Given the visual feedback to the user of the prominent point moving along the 1-D manifold, this may be good enough. If it isn't, the next iteration would be for the CellImpl to compute the closest point on the 1-D manifold to the ray defined by the manipulable point. You might get this ray by converting from the Data coords of the manipulable point to (XAxis, YAxis, ZAxis) via the ScalarMaps, then pass this to MouseBehaviorJ3D.cursorRay() to get the ray. But only do this ray business if the firts approach isn't good enough. Given the general utility of this answer, I will take the liberty of CC'ing to the list.
In either case, the suggestion of having the indicator on the line not be the manipulable one is the way to go. I'll just move it with either another manipulable point or a display listener. We already have the latter on the IDV map display, so it might just be a matter of connecting to that. Thanks again. Don ************************************************************* Don Murray UCAR Unidata Program dmurray@xxxxxxxxxxxxxxxx P.O. Box 3000 (303) 497-8628 Boulder, CO 80307 http://www.unidata.ucar.edu/staff/donm "Time makes everyone interesting, even YOU!" *************************************************************
visad archives: