Hi again, Hazen, all: I just noticed that the patch I sent contains a bug. I used malloc where I ought to have used calloc in one place.
Would it be possible for me to get SVN access so I can just fix this myself? I'd also like to look into the possibility of adding optional alpha channel support for the memcairo driver in the future. Thanks much! --Doug Hunt [EMAIL PROTECTED] Software Engineer III UCAR - COSMIC, Tel. (303) 497-2611 On Sun, 9 Mar 2008, Hazen Babcock wrote: > > 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
