This line symbol type is designed to replicate the ArcGIS Hash Line
symbol layer type. It allows for a repeating line segment to be
drawn over the length of a feature, with a line-sub symbol used
to render each individual segment.
To reduce code duplication, this is heavily based off the current
line marker symbol layer, since the functionality is almost
identical (draw some sub symbol at some interval along a line).
Accordingly, I've split off QgsMarkerLineSymbolLayer to move
as much of the common functionality as possible to a new abstract
base class, so that only the actual marker/line segment rendering
occurs in the marker line/hash line subclasses.
This also gives the hash line all the existing placement options
permissible for marker lines -- e.g. first/last vertex, mid points,
regular intervals, etc.
The hash line length and angle can have data defined overrides,
which are evaluated per-line segment, allowing for the hash line
to change size and angle over the length of a single rendered
feature.
are displayed
Turns out there is NO reliable way to create a proxy model
which adds new rows to a model, so just bite the bullet and
do it in the underlying model (yuck)
Fixes:
- enum parameters set to "allow multiple" only allow a single
value selection when used in modeler
- optional enum parameters cannot be set to no value when
used outside of modeler
Fixes#20406
And add a Processing setting to allow these to be shown. When shown, they
are highlighted in red with a tooltip explaining that the algorithm
has known issues
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!
* fixes#20516 : Allow Constraint widget in attribute type form to be empty so expression could be removed
per widget modification
* correct tests
* Add the clear button on field expression widget when widget is allowed to be empty
* Change API since version to 3.6
If they are deleted, any other python wrappers which have been parented to these singletons are deleted too.
One of the most common issues with this is, that subclasses of registry items are deleted and lost.
