Attempts to set the input band for the renderer.
Returns TRUE if the band was successfully set, or FALSE if the
band could not be set.
This was implemented in various raster renderer subclasses,
but it was necessary to down cast and then call the individual
methods (which don't have consistent names!).
Instead, add a top level virtual method so that it's easy to
change the input band for the renderers.
Allows raster nodata pixels to be colored in a specific (non-transparent) color.
Designed to match the "Display background value" option from ArcMap.
Sponsored by SLYR
Fixes#26087
Adds a new visitor pattern API for creation of visitors which visit
all the style entities (symbols, color ramps, text formats, and
label styles) associated with different objects. Can be used on a
renderer, map layer, or project wide level.
E.g. on a project wide level, allows collection of ALL the style
symbols/color ramps/text settings inside a project, including those
in layouts or annotations!
