to have a file filter string defined
Previously only an extension was settable, which prevented use when
multiple extension types are possible. A file filter string allows
for flexible file selection instead.
In processing, if an algorithm has a boolean as an output, it cannot be defined as boolean but as a number.
To be more precise in algorithms description, the commit add QgsProcessingOutputBoolean.
which will be available to a parameter when it is evaluated.
Specifying variables via this method is for metadata purposes only.
It is the algorithm's responsibility to correctly set the value of
these additional variables in all expression context used when evaluating
the parameter, in whichever way is appropriate for that particular variable.
This adds a new parameter type specifically for map scales,
QgsProcessingParameterScale. The values are evaluated using
self.parameterAsDouble, which returns the map scale
denominator (matching the standard in other parts of the
QGIS API).
Scale parameters are displayed to users using the standard
QgsScaleWidget, which includes the combo box of predefined
scales and a shortcut button to match the current map scale.
Returns a descriptive list of the possible string values acceptable
for the parameter.
E.g. for a QgsProcessingParameterVectorLayer this may include
"Path to a vector layer", for QgsProcessingParameterBoolean
"1 for true, 0 for false" etc.
For the c++ api dox this expands to "\c nullptr" (the
\c directive indicates a code literal value), and for sipify/Python
it expands to ``None`` (`` is sphinx annotation for literal values)
Makes for nicer dox for both c++ and Python!
Instead of requiring clients to generate temporary file names themselves,
(or use the cryptic "memory:" string!), this PR adds a static constant
QgsProcessing.TEMPORARY_OUTPUT
If a layer/sink output parameter is set to QgsProcessing.TEMPORARY_OUTPUT,
then the temporary output filename will be generated automatically at
algorithm run time. This means callers don't need to mess around with
finding appropriate temporary folders and paths.
Another benefit is that TEMPORARY_OUTPUT is stored in the processing
history, so if you re-run a previous algorithm which was set to
output to a temporary file, it no longer tries to use that same
previous temporary path and instead generates a new one.
This adds a new available parameter type for processing algorithms,
QgsProcessingParameterAuthConfig, allowing selection from available
authentication configurations (and creation of new ones).
It allows creation of processing algorithm which can fully take
advantage of QGIS' mature authentication handling, avoiding the
need to use insecure string parameters for users to input
sensitive logon credentials.
QgsProcessingParameterAuthConfig parameters are evaluated using
QgsProcessingAlgorithm.parameterAsString(), which returns the
selected authentication configuration ID.
to show in numeric/distance widgets
E.g. to only show 2 decimal places:
# only show two decimal places in parameter's widgets, not 6:
param.setMetadata( {'widget_wrapper':
{ 'decimals': 2 }
})
