QGIS processing scripts - restrict vector input to geometry type

Question

In QGIS processing scripts we define input vector layers by

##inputlayer=vector

wich in the gui generates a drop down list from what the user can select one of all available layers.

Normaly, processing is defined for only one distinct geometry type, let's say Point. If the project contains of a great bunch of, let's say Line Layers, we have all these Line layers in a dropdown, where only the Point layer should be selectable.

So the question is:

In QGIS processing scripts, is there a way to restrict vector input to certain geometry type (sth. like ##input=vector point)?

Answer 1

The guess in my question really works. So as I have tried so far the declarations

##input_points=vector point
##input_lines=vector line
##input_polygons=vector polygon

are valid and restrict the combo box to the declared geometry type.

Answer 2

In QGIS 3.x suppose you have an input file, using the template file it uses the following code:

def initAlgorithm(self, config=None):
    """
    Here we define the inputs and output of the algorithm, along
    with some other properties.
"""

# We add the input vector features source. It can have any kind of
# geometry.
self.addParameter(
    QgsProcessingParameterFeatureSource(
        self.INPUT,
        self.tr('Input Layer'),
        [QgsProcessing.TypeVectorAnyGeometry] # accepts any geometry
    )
)

The default input will look like this in the tool:

You can change the default line [QgsProcessing.TypeVectorAnyGeometry] that accepts any geometry to use only specific geometry as follows:

[QgsProcessing.TypeVectorPoint] # accepts only point geometry.
[QgsProcessing.TypeVectorLine] # accepts only Line geometry.
[QgsProcessing.TypeVectorPolygon] # accepts only polygon geometry.

In case of point geometry the tool will look like this after customising the above line for point geometry:

In case of polygon geometry the tool will look like this after customising the above line for polygon geometry: