Aside from the performance benefits, the Python version of this
algorithm occasionally fails on Travis with odd errors. Hopefully
by porting to c++ it will fix these, or at least give useful
debug information in the event of a fail.
Also add support for curved input geometries.
- Output interpolated points when travel cost falls mid-way along
an edge
- Output all intermediate reachable points also
- Make outputting upper/lower bound points optional, and non-default.
Now by default we just output all definitely reachable points and
the interpolated points along edges which correspond to the travel cost.
This allows the output to be used to correctly generate service areas
e.g. by concave/convex polygons and all reachable nodes will be
included in the area.
- Allow algorithm to optionally output a line layer (and make the
point layer optional too, and default to just the line layer output)
containing all reachable line segments (including interpolated
segments of lines when the travel cost sits midway along that
edge). This output is more easily understandably for users.
Instead of returning a single QgsFeature from processFeature, we now
return a list of features.
This allows feature based algorithms which return multiple features
per input feature, e.g. "explode" type algorithms which split a
single input feature into multiple output features.
always add a consistent amount of attributes regardless of the
code paths taken
Some algorithms were adding features to data providers with
different number of attributes vs the layer's fields - this is
not supported and depending on the data provider will have
different (bad) results.
be prepared
There's cases where this happens without reflecting an invalid
expression. So we can try to prepare, but not abort if the
preparation fails.
Fixes#18103
- Fix missing format call for string when calculated number
of points is 0
- Fix incorrect progress reports which were spamming the dialog
and causing UI hangs, and slow algorithm execution
