Adds a new QGIS processing provider for 3d algorithms, available
only when QGIS is built WITH_3D
Currently includes only a single algorithm for tesselating geometries,
which exposes the functionality of QgsTesselator to processing.
Like the native c++ algorithm provider, algorithms in the 3d
provider are transparently merged with the other QGIS providers
(i.e. they aren't separated into their own group)
This change ensures that searching for algorithms always returns
native algorithms before matching 3rd party algorithms
TODO: we really need to replace the toolbox tree with a proper
model and redo the sorting/filtering using a sort/filter proxy
model.
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.
in processing toolbox
Helps aid in user discoverability of these algorithms, and
indicates to users that these should generally be the
preferred algorithm choices if duplicates exist from other
providers.
This somewhat changes the meaning of outputs from processing 2.x.
In 2.x processing outputs were used both as a method of specifying
inputs to algorithms (file paths to destination layers created
by the algorithm) AND pure outputs (such as statistics calculated
by the algorithm).
This is now split. The old input-type-outputs (destination layers)
are now input parameters (since the parameter value IS an input to the
algorithm). To differentiate them from parameters indicating pure
input layers a new "isDestination()" method was added to
QgsProcessingParameterDefinition.
Output definitions are now purely indications of values CREATED
by the algorithms. Suitable candidates are the existing calculated
stats and actual file path/URI of any layers created by the algorithm.
Moving forward we should ensure all algorithms output as much
useful information as possible - e.g. number of features processed,
number of skipped features, count null geometries encountered, etc...
Add an interface method to show the options dialog at a specific
page. This is required since plugins can now embed their options
in the main options dialog, so they may also need a way to
force this dialog to open.
Implement this in processing so that enabling additional providers
works again.
