Dave Howorth escribió: > Martin (OpenGeoMap) wrote: > >> I am building an intermediate unit system for engineeres in Gobject and >> i hope publish this library soon. >> With this system you always work in lineal measures in meters (double), >> and you can input others (inches, centimeters) >> >> input system - intermediate system -out system >> >> you can input in a entry for example (22m, 22 m, 220cm,...) and >> internally you have a double always in meters. >> > > How do you deal with precision? 22 m is not the same as 22.000 m > >
Internally you always have doubles, but you show to the people only 3, 2 or 0 dezimals,... You have 16 mantise numbers: 1234.567890123456 123456.7890123456 123456789.0123456 12345678901.23456 In DXF files for example you see always 16 numbers . This is the double precision IEEE standard: This is explained very well in GSL API: http://linux.duke.edu/~mstenner/free-docs/gsl-ref-1.1/gsl-ref_38.html The important here in mantain the double (16 numbers) in an intermediate system. It doesn`t matter what you see in a gtk_entry (22.34555, 22.346,22.35,). Regards. _______________________________________________ gtk-app-devel-list mailing list gtk-app-devel-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-app-devel-list
