Also exposes this capability to modeler - so that model algorithms
can use data defined parameters within their child algorithms.
TODO:
- tests
- setting the associated vector layer
A new widget which handles parameter values for child algorithms
within a model. Instead of the previous approach of requiring
individual widget wrappers to handle creation of a suitable
model widget, we do all this automatically for them.
This widget uses a stacked widget with a toolbutton to select
the parameter's source, instead of the previous combo box approach
(which didn't scale well for large models). I.e. users select
first whether the value is taken from a static value, a
model input, or an output from a different child algorithm. The
widget then changes appearance and behavior based on this
choice.
Additionally, a new option is present for all parameters
of using a "precalculated expression". This expression is
evaluated once before the child algorithm is executed
and used during the execution of that algorithm.
- Add abstract base class for Processing widget wrappers to c++
- Add wrapper factory interface to c++
- Make QgsProcessingGuiRegistry also register widget wrapper
factories, and be responsible for creation of new c++
processing widget wrapper instances
- Start on private c++ implementation of boolean widget wrapper,
including unit tests
When an algorithm has a distance parameter in meters/feet/etc (i.e.
non-geographic distances), show a combo box allowing choice of
unit type.
(We don't (and should never) expose this for distances in degrees --
it's up to users in this situation to choose a suitable local
projection and reproject their data to match. Refs: a recent
talk by @volaya)
Fixes#19329 (https://issues.qgis.org/issues/19329)
Optional layer parameters in processing algorithms used in the graphical modeler
add an empty string as the default parameter value, which can raise an exception
during algorithm execution. This update replaces the default empty string with a
default 'Not selected' option.
It turns out that an empty QComboBox evaluates to False:
>>> t=QLineEdit()
>>> bool(t)
True
>>> c=QComboBox()
>>> bool(c)
False
Due to that, the 'TABLE' parameter was missing if its (editable) combo box was empty.
Original error - while updating an algorithm's parameters (gdal:importvectorintopostgisdatabaseavailableconnections)
Traceback (most recent call last):
File "/home/martin/qgis/git-master/build-debug/output/python/plugins/processing/algs/gdal/GdalAlgorithmDialog.py", line 121, in parametersHaveChanged
or (not p.checkValueIsAcceptable(parameters[p.name()])):
KeyError: 'TABLE'
their underlying algorithm's provider
E.g. for model outputs generated by a saga algorithm, only
sdat and shp files are valid outputs. So only give users choices
of these instead of all formats.
Also fixes temporary file names generated as part of model
execution may use formats which are not compatible with the
algorithm's provider.
Fixes#18908
