I have modified the code as you suggested: GimpRGB *colore; GimpChannelOps parametri; gboolean success; gimp_rgb_set_uchar(colore, pixel[0], pixel[1], pixel[2]); parametri = GIMP_CHANNEL_OP_REPLACE; success = gimp_by_color_select(drawable->drawable_id, colore, termogramma.scarto, parametri, FALSE, FALSE, 0.0, FALSE); The compiler returns me no error but when I execute the gimp return a fatal error: "segmentation fault". I think the problem is in one of this line but, with my few experience, I can't find it... >> Hi, >> I think I already pointed you to the API reference for GimpRGB and > gimp_rgb_set_uchar() in particular. GimpChannelOps is an enum and the > possible values are listed in the API reference. Just follow the link. >> You can also save yourself the hassle of working with pixel regions if > all you want to do is to get the color of a single pixel. There's gimp_drawable_get_pixel() for that purpose. >>> Sven>> _________________________________________________________________ Crea i tuoi biglietti da visita con Windows Live Messenger! http://www.messenger.it/biglietti_da_visita.html _______________________________________________ Gimp-developer mailing list Gimp-developer@xxxxxxxxxxxxxxxxxxxxxx https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-developer