bool
CanvasView::on_duck_angle_changed(const synfig::Angle &rotation,const synfigapp::ValueDesc& value_desc)
{
+ if (ValueNode_BLineCalcTangent::Handle bline_tangent = ValueNode_BLineCalcTangent::Handle::cast_dynamic(value_desc.get_value_node()))
+ {
+ int offset_index(bline_tangent->get_link_index_from_name("offset"));
+ Angle old_offset((*(bline_tangent->get_link(offset_index)))(get_time()).get(Angle()));
+ return canvas_interface()->change_value(synfigapp::ValueDesc(bline_tangent,offset_index), old_offset + rotation);
+ }
+
// \todo will this really always be the case?
assert(value_desc.get_value_type() == ValueBase::TYPE_ANGLE);
return canvas_interface()->change_value(value_desc, value_desc.get_value(get_time()).get(Angle()) + rotation);