Re: Shouldn't Cairo use/offer degrees rather than radians?
Bill Spitzak <[email protected]>
| Newsgroups | gmane.comp.lib.cairo |
|---|---|
| Message-ID | <CAL-8oAhqtK20sGVdGBNq3ZMSRJver0hUSV7vpEoEq6=uufLhJw@mail.gmail.com> |
I had to change the format to CAIRO_FORMAT_ARGB32 to get this to work (otherwise I got CAIRO_STATUS_INVALID_FORMAT) and my output image is "correct" in that both ends are the same y pixel. The path prints exactly the same numbers as you show. I suspect fiddling with your y value would get the error back however. On Thu, Jul 6, 2017 at 10:37 AM, Andreas Lobinger <[email protected]> wrote: > Hello colleague(s), > > On Wed, Jul 5, 2017 at 10:37 PM, David Kastrup <[email protected]> wrote: > >> With this print format, the numbers would look the same. Do they >> compare equal when comparing them with == ? And/or can you print with >> something like 20 significant digits? >> >> The reason I ask: if the y coordinates of the curveto are _exactly_ >> identical, this artifact would not actually be a consequence of >> trigonometric functions unless cairo_copy_path is responsible for >> minuscule changes as well. > > step1: i'm attaching the c-code i used to print the data > step2: output (with %.20f) > > lobi@orange4:~/juliarepo$ gcc attachment1.c -I/usr/include/cairo/ -lcairo > lobi@orange4:~/juliarepo$ ./a.out > moveto 20.00000000000000000000,0.50390625000000000000 > curveto 20.00000000000000000000,7.16796875000000000000 > 10.00000000000000000000,7.16796875000000000000 > 10.00000000000000000000,0.50390625000000000000 > > (and i'm pretty much convinced that path_copy just copies data without > interfering) > > Without further debugging or looking into the code i'd assume we see > here the process of cairo modeling the arc piecewise by curveto > operators. And in this case a single curve - regarding the scaling and > resolution of the output device seems to be enough. > > step3: please run and post. I'm really interested how your cairo is > creating a different curve. > > -- > cairo mailing list > [email protected] > https://lists.cairographics.org/mailman/listinfo/cairo -- cairo mailing list [email protected] https://lists.cairographics.org/mailman/listinfo/cairo