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.
This is a subclass of QgsProcessingParameterNumber, but specifically
for numeric parameters which represent distances. It is linked
to a parent parameter, from which the distance unit will
be determined, and is shown using a dedicated distance widget
within the processing parameters panel. This widget shows
the distance unit.
This avoids the confusion when running algorithms which
use distances where the unit depends on a layer or CRS parameter -
e.g. the distance parameter in the buffer algorithm gives
the distance in layer units... so now we can show those units
directly within the dialog. Hopefully this leads to less
user confusion and accidental "1000 degree buffers"!
Additionally - if the unit is in degrees, a small warning
icon is shown next to the parameter. The tooltip for this
icon advises users to reproject data into a suitable
projected local coordinate system.
Initially implemented for the native buffer and single
sided buffer algorithm only - but more will be added.
Fixes#16290
ModelerParametersDialog and ParametersPanel have to keep list of
wrappers only. widget and label( if needed) are created through
WidgetWrapper.createLabel()
in model child algorithms
Prior to this change if you edited an algorithm in a model and
tried to enter a preset string for certain parameter types, this
string would get silently discarded on closing the dialog. E.g.
with a dissolve algorithm it was not possible to have a fixed
field name within the model to dissolve by.
This was caused by WidgetWrapper.comboValue returning the customData
for these manually entered values in the parameters combo box,
yet manually entered values never have custom data.
To work around this we only return the custom data if its
set for the selected item - otherwise we return the text unchanged.
In order to handle the "[not set]" options, a new static custom
data value of WidgetWrapper.NOT_SET_OPTION is added to that
comboValue can detect this and return the appropriate None value.
This was a missing capability in the processing API - while algorithms
could declare multiple layer input parameters, there was no corresponding
multi-layer output. This meant that algorithms (such as Package Layers,
Vector Split) which create a set of layers which cannot be determined
in advance had no way to pass these generated layers on for further model
processing steps.
It's also useful for algorithms which operate on a specified folder,
processing all layers found there, and allowing these generated
outputs to be utilised in other model steps (e.g. packaging
all of them, merging them, etc)
When running algorithms through the toolbox, which have dynamic
numeric parameters, add a data defined property override button
next to the widget so that users can set the overrides for these
parameters.
Previously this was available only in the backend, but not
exposed anywhere in the GUI.
Note that currently no algorithms support dynamic parameters,
so don't expect to see this everywhere. It's also only available
in toolbox/batch processing modes, not in models.
Since these expressions were only evaluated immediately, it led to
confusing behavior for users who were expecting that the expression
would be applied per-feature.
Given that expressions can be directly entered into spin boxes, we already
have a way of users evaluating simple calculations for numeric
parameters at least.
I don't think there's a strong enough use case for needing to
calculate string results to leave the confusing expression builder
option in place.
This should be re-evaluated when we add UI support for dynamic
parameters (which are already supported in the backend), where
expressions are evaluated per-feature.
Fixes#17267
* A new createopt textbox has been added to the parameters dialog for algorithms which exports to raster files.
* A new metaopt textbox has also been added to the Algorithm parameters dialog.
* Raster file format is detected from output filename extension.
* GdalUtils has been improved to correctly detect raster formats supported for creation.
* QFileDialog for output rasters now display only file filters for supported output raster file formats.
Previously we took a harsher approach to filtering which inputs
were acceptable for child algorithm parameters. E.g. a child algorithm
with a vector layer input would only show outputs from other algorithms
which generated a vector layer output.
But this can needlessly restrict what's possible in models. E.g.
an algorithm which outputs a QgsProcessingOutputFile or
QgsProcessingOutputString could potentially be a valid source
to a vector layer. So we should allow these as possible
inputs for vector layer parameters too.
This commit adds many extra acceptable input types for
child parameters. It will probably expose "corner cases" where
algorithms may get unexpected input types, but these will
not affect existing model stability and can be fixed when
identified.
The payoff is a much more flexible modeler.
