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
Since it's safe to evaluate parameters in background threads
now, it's usually going to be ok to evaluate everything in
the processAlgorithm step.
This keeps the algorithm code as simple as possible, and will
make porting faster.
Note that the prepare/postProcess virtual methods still exist
and can be used when an algorithm MUST do setup/cleanup work
in the main thread.
require all input layers to be in the same CRS
The default behaviour is to assume that algorithms are well behaved
and can handle multi-CRS inputs, but algs have the option to
flag that they do not allow this and require the input CRS check.
Those algs should document that they require all inputs to have
matching CRS - processing 3.0 behaviour is to assume that algs
can handle this.
Intended as a registry for the various processing components,
including providers, algorithms and various parameters and outputs.
Currently handles only registration of providers, as a step toward
removing processing's algList (this requires first porting
the algorithm class to c++)
A QgsProcessingRegistry instance is attached to QgsApplication,
and is retrieved by QgsApplication::processingRegistry()
Nothing particularly exciting here yet, but this commit
moves the definition of the provider base class to a c++
QgsProcessingProvider abstract base class.
As part of this some existing python methods were renamed
to make their use clearer and to fit with the QGIS c++
api conventions:
- getName was renamed to id
- getDescription was renamed to name
- getIcon was renamed to icon
These API breaks are documented
spell check will be done automatically in words by default (when some conditions are fulfilled)
possibility to avoid in words checking by adding :* at the end in spelling.dat
one can add #spellok at the end of a line of code to skip spell check on this line
