Hi all,
While fixing bug #1227193 i have encoutered strange behaviour of SPGenericEllipse. When a new ellipse is drawn, the "d" attribute in corresponding svg:path element is set by SPGenericEllipse::write and contains arcs. However in SPGenericEllipse::update_patheffect, triggered by document idle handler, "d" attribute is regenerated from SPCurve and has other value. Instead of two arcs there are four curve elements.
I would like to address this issue. Since those are my first steps in inkscape development, I have some quesions. 1) Should I add arcto method to SPCurve and make both SPGeneralEllipse methods generate the same "d" attribute value? 2) Why there are two different methods that generate "d" attribute value? Should one of them (sp_arc_set_elliptical_path_attribute or sp_svg_write_path call in update_patheffect) be removed? 3) Should static function sp_arc_set_elliptical_path_attribute be c++-fied to private member method?
Regards, Tomasz Boczkowski
Hi Tomasz,
- Should I add arcto method to SPCurve and make both SPGeneralEllipse
methods generate the same "d" attribute value?
- Why there are two different methods that generate "d" attribute value?
Should one of them (sp_arc_set_elliptical_path_attribute or sp_svg_write_path call in update_patheffect) be removed? Be careful as there are three different classes mixed in this single file: SPEllipse, SPCircle, and SPArc. I'm not sure whether there is a good reason for creating different methods for generating the d attribute value. Maybe that's just because different people worked on that. Note that SPCurve should be eliminated from as many places as possible in favor of 2geom. I'll show you a simple example:
// Old void SPDropperContext::setup() { ... SPCurve *c = new SPCurve(); const double C1 = 0.552; c->moveto(-1,0); c->curveto(-1, C1, -C1, 1, 0, 1 ); c->curveto(C1, 1, 1, C1, 1, 0 ); c->curveto(1, -C1, C1, -1, 0, -1 ); c->curveto(-C1, -1, -1, -C1, -1, 0 ); c->closepath(); ... }
// New void SPDropperContext::setup() { ... Geom::PathVector path; Geom::Circle(0, 0, 1).getPath(path);
SPCurve *c = new SPCurve(path); // SPCurve used only as a wrapper ... }
So if you like geometry, this is a nice job to do ;) .
- Should static function sp_arc_set_elliptical_path_attribute be c++-fied
to private member method? Yes, that's a leftover of my refactoring, I simply didn't have the time yet to turn all these functions into members.
Regards, Markus
participants (2)
-
Markus Engel -
Tomasz Boczkowski