Instead of a separate Points In Polygon algorithm just for this
extra option, add it to the original Points In Polygon algorithm
as a non-default option.
The dialogs are parented to the main window, which means sip
transfers the ownership to the main window - and they are
never deleted as a result. This results in various error
messages caused by the widgets hanging around forever
and listening out for various signals they are connected to.
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.
and pure virtual createInstance
Allows us to add logic which always need applying within
create(), leaving createInstance() free to just return a
raw new instance of the class
Well... kind of. It fixes the toolbar button size, but for some
reason the actual icon content itself isn't being resized. I can't
work out why this is...
The previous naming was too easily confused with processing outputs.
Rename them to QgsProcessingParameterFileDestination, etc... to
make it clearer what they are used for.
model execution
And use this function to determine in advance dependencies between
child algorithm parameters with expression based values and
which other child algorithms they depend upon.
