Michael Lawrence <lawrence.michael <at> gene.com> writes: > > The objects in RGtk2 (and cairoDevice) are externalptr objects in R. One > approach would be to create an externalptr in C, and then call some R code > that sets the class attribute accordingly, i.e., to the result of > gTypeGetAncestors("GtkDrawingArea"), and then calls asCairoDevice() on that > object. > > Michael >
Thank's Michael but I don't understand how to do what you've explained. How can I change an external pointer (created in C) to be an GtkDrawingArea using R? What I've tried so far is: -1-store the existing GtkDrawingArea* from my app in a DLL callable variable -2-set up a DrawingArea in R with: DA <- gtkDrawingArea -3-call the DLL-function with .Call ("R_Interface_get_da", DA ) -4-the DLL-function R_Interface_get_da takes DA as an SEXP and lets it point to the variable created in step 1 (i.e. my apps DrawingArea). Doing it that way I thought DA would be an object of the correct class allready, because I only let it point to some other DrawingArea. But that doesn't work in conjunction with asCairoDevice. Thomas _______________________________________________ R-SIG-GUI mailing list R-SIG-GUI@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-gui