On Mar 6, 2008, at 6:52 PM, Doug Hunt wrote: > Hi Hazen, all: I think I was able to get the memcairo driver > working. Attached is a patch to plplot-5.9.0:drivers/cairo.c. > > The immediate problem was that the X and Y dimensions of the plot > were not correct in plD_eop_memcairo. The PLstream record values > pls->phyxma and pls->phyyma were updated during plotting (made > larger) so that when the cairo drawing surface memory was copied > back out to the user-supplied memory area, a SEGFAULT occurred. > > I replaced pls->phyxma and pls->phyyma in the loop with pls- > >xlength and pls->ylength (these were set up for this purpose in > plD_init_memcairo) and that seemed to do the trick. > > The other changes I made were more basic. It seems that the > memcairo driver as it stands was designed to overwrite the user- > input memory area, initializing it to all black. This behavior is > not useful, as the purpose of the 'mem' drivers (as I understand > it) is to be able to add decoration to a user-supplied image (see > the attachment). > > In order to get this behavior, I had to initialize the cairo > drawing surface with the user-input memory area, using > > 'cairo_image_surface_create_for_data' > > instead of > > 'cairo_image_surface_create'. > > I also added an empty subroutine plD_bop_memcairo which is used > instead of plD_bop_cairo. This is done because plD_bop_cairo > zeroes out the image, which is not what is desired. > > Please take a look at this patch and consider including it in > plplot. It has no effect on any driver other than memcairo.
Hi Doug, It looks good. I applied it and now the memcairo driver works as expected (v8261). Thanks for your work to make this driver functional. best, -Hazen ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Plplot-devel mailing list Plplot-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/plplot-devel
