to Processing. These are useful for 3rd party tools as outputs can be
automatically loaded on algorithm completion.
It is an API change not visible for users.
for layers
There's two reasons why someone would be calling this method:
- to determine which layers should be rendered by a render job
- to determine which layers are actually visible in the map
Depending on which is required, we either want to expand out
groups and remove the group layer itself from the list (or not)
A group layer is a map layer which consists of a set of
child layers, where all component layers are rendered as a single
flattened object during map renders.
This commit sets up the base framework for QgsGroupLayer only
(i.e. no rendering changes).
a static value in a specified QgsExpressionContext
Allows us to short-cut some calculations, e.g. by pre-evaluating
the property once during a QgsSymbol startRender instead of once
for every feature rendered.
whether the first/last vertex option should respect multipart geometries
The default is not to respect these, so first and last vertices
are symbolized for every part of a multi-part geometry (this matches
the old behaviour). By opting in to the "respect multipart geometries"
option, the symbols will only be placed on the VERY first or very LAST
vertex in the whole multi-part geometry.
Sponsored by North Road, thanks to SLYR
with "on inner vertices"
This new mode places the symbols on all inner vertices (ie all
vertices except the first or last). (We can safely do this now
that its easy for users to also set the symbols to show on
first/last vertex by clicking those checkboxes too!)
The motivation here is that when the "Vertex" mode puts the
symbols on the first/last vertex as well as inner vertices,
it's basically impossible to style a line with a different
marker on the first/last vertex to the rest of the line's
vertices. (The best you can get is just hiding the unwanted
first/last vertex by overlaying a second symbol layer on
the first/last vertices with a larger symbol)
Sponsored by North Road, thanks to SLYR
Makes it considerably quicker to create a marker line with the
markers on the first AND last vertex, amongst other things...
Fixes#18433
Sponsored by North Road, thanks to SLYR
