options should be available for certain model outputs and script
algorithm outputs
We do this by swapping the test for non-file based output support
from checking only the algorithm's provider to instead checking
on a parameter-by-parameter basis.
This is done in order to support models. For models, depending
on what child algorithm a model output is based off, an individual
model may or may not have support for non-file based outputs. E.g
a model may generate outputs from a native qgis alg (supporting
these outputs) AND an output from a GDAL alg (with no support
for these outputs). In this case we need to enable or disable
the ui controls for non-file based outputs on an individual
output basis.
For scripts (for now) we blindly just say all outputs support
non-file based formats. This is going to be the case most of
the time, since scripts will usually be written using PyQGIS
API. For the exceptions (e.g. scripts which call other algs
like GDAL algs) we probably should add some way for the script
to indicate whether an individual output supports this, but
for now we just say they all do.
Fixes#17949
I realise this adds another toolbar button... but I'd strongly
argue that the toolbox is used FAR FAR more often than many of the
other toolbar actions!
Brings the behaviour into line with the styling dock, where
the action is checkable and checked only when the toolbox
is open AND user visible (i.e. not hidden behind another tab). If
the toolbox is open but hidden, then hitting the Toolbox action
brings it to the front tab.
Otherwise it's often necessary to hit to Toolbox shortcut twice -
once to close a hidden toolbox tab, and a second time to open
and raise it.
And implement some fixes/improvements (refs discussion on the dev mailing list):
- allow user to specify created field name
- allow optional creation of a summary table showing new class value vs original
value
This algorithm has become a model-only algorithm, since it's
functionality is now present in the native c++ buffer algorithm
(which can now buffer by field or expression).
Ideally we'd remove this algorithm entirely, but data defined
parameters are not yet supported by the modeler gui, so we need
to keep it around for use in models for now.
...to help clarify for users what the different input types mean.
Fixes#17671, which is a result of unclear distinction between
the uses of vector features vs vector layer inputs.
Tagged as needs-docs, as it may help with documentation for 3.0
Ensure that dialogs are always correctly deleted when appropriate.
Also, if an algorithm is running in a background task and hits
an error, we automatically re-show the algorithm dialog and the
associated log for debugging.
Fixes#16858
A much better way of doing this would be to have the dialog extend qgsprocessingalgorithmdialogbase, or to take an approach like the one used in the raster calculator, with wrapper widgets.
This is just a patch, since that option might require a larger amount of work.
which cannot run in background tasks
This is not fantastic UX, but we have lots of constraints here:
- The algorithm dialog itself cannot be made modal. There's child
widgets (such as the point and extent parameter widgets) which
interact with the main QGIS window.
- There is no reliable way in Qt to make a dialog modal after
it's shown (e.g. make it modal only when the algorithm is
running). Trust me - I've tried everything, and all approaches
break with some corner case.
- For non-background algorithms, we must have processEvents calls
in order to show the algorithm feedback and progress to users,
and detect cancel button clicks. Yet these processEvents calls
means that users can interact with other parts of QGIS, e.g.
removing layers from a project, and other operations which
could cause the algorithm to crash. So we MUST have some modal
dialog in order to block interactions outside of allowing
the cancel button clicks/progress repainting.
I've tried many approaches, but this is the only one which
works reliably...
