Include descriptive text with the specified parameter value
in error, and always check that sources were loaded to avoid
raw Python exceptions when they are not
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.
Inside the modeler, there is not enough knowledge about the layer on
which the refactor fields algorithm will run.
Let's be graceful with error messages here therefore.
And use it when we need to clone parameters (instead of more fragile
conversion to and from variants)
This fixes model loading which use algorithms which create python
subclasses of parameter definitions
Check that all parameter's values pass the validity check,
even if not returned as QgsProcessingModelChildParameterSource.
In case of list, tests that it is really a QgsProcessingModelChildParameterSource list,
and create a QgsProcessingModelChildParameterSource from the list if it is not the case
(useful for custom parameters that return lists as ParameterFieldsMapping).
initAlgorithm() method
This allows 2 benefits:
- algorithms can be subclassed and have subclasses add additional
parameters/outputs to the algorithm. With the previous approach
of declaring parameters/outputs in the constructor, it's not
possible to call virtual methods to add additional parameters/
outputs (since you can't call virtual methods from a constructor).
- initAlgorithm takes a variant map argument, allowing the algorithm
to dynamically adjust its declared parameters and outputs according
to this configuration map. This potentially allows model algorithms which
can be configured to have variable numbers of parameters and
outputs at run time. E.g. a "router" algorithm which directs
features to one of any number of output sinks depending on some
user configured criteria.
have specific icons, instead of generic qgis icon
We consider these 'top level' algorithms, and using the
standard algorithm icon should help reflect this and
differentiate them from 3rd party algorithms.
Algorithms and other processing code should use this method
(instead of dataobjects.getLayerFromString) to
retrieve layers from a string, as it considers the processing
context and allows resolving strings to temporarily stored layers.
This permits processing models to function correctly when
intermediate results are stored as memory layers. Subsequent
model algorithms can then access these temporary layers as inputs.
All temporary layers will be removed when the context object
is destroyed after the model algorithm is run.
- setEllipsoidalMode() was removed. Ellipsoidal calculations are
now enabled whenever a valid ellipsoid() has been set. Set the
ellipsoid to 'NONE' to disable ellipsoidal calculations.
- ellipsoidalEnabled() was removed. Ellipsoidal calculations
are now enabled whenever a valid ellipsoid() is set. Check
willUseEllipsoid() to determine whether ellipsoidal
calculations will be performed.
- sourceCrs() and setSourceCrs() now always take and return
QgsCoordinateReferenceSystem objects. All string/ID based CRS
methods were removed.
- geographic() was removed. This was only used internally
in one place, so was replaced with sourceCrs().isGeographic() instead.
- some largely overlapping measurement functions were consolidated
Also
- simplify and add tests
- remove large memory leak (persistant store of all non-project layers)
- remove broken support for direct loading postgres/virtual layers
by string (Python version was very broken and would never match
a postgres/virtual layer)
