Adds an explicit choice between SVG or raster image sources,
which allows us to clean up the configuration panel for layout pictures
by hiding options which don't apply to a certain picture source. Also permits
us to:
- Reuse the standard svg selector tree widget, which loads images
in a background thread and fixes#17061
- Uses the standard SVG and image selector line edit, which permit
drag and drop of images and expose options to embed images
and link to online sources
Ultimately this is motivated by a desire to allow users to embed
images in layouts and layout templates
Sponsored by SLYR
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, only rasterize that one item and pre-apply it's opacity
to the rasterized version. This keeps all the rest of the layout
content as vectors/text.
Checks whether a function declaration has parameters that are
top level const.
const values in declarations do not affect the signature of a
function, so they should not be put there.
