This feature allows other layout items (such as scalebars,
north arrows, inset maps, etc) to be marked as a blockers for
the map labels in a map item. This prevents any map labels from
being placed under those items - causing the labeling engine
to either try alternative placement for these labels (or
discarding them altogether)
This allows for more cartographically pleasing maps -- placing
labels under other items can make them hard to read, yet without
this new setting it's non-trivial to get QGIS to avoid placing
the labels in these obscured areas.
The blocking items are set through a map item's properties, under
the label settings panel. The setting is per-map item, so you can have
a scalebar block the labels for one map in your layout and not others
(if you so desire!)
should show partial labels
Layout map items no longer respect the default project setting
for "show partial labels", and instead have their own, per map
setting for this option. (Under the map item properties,
labeling settings button).
The map item setting always defaults to off (unlike the canvas
setting, which defaults to true for a new project) as layouts
should always default to the settings which produce the highest
quality cartographic outputs.
In general I suspect that most users would always want to avoid
rendering partial labels in layouts, but this setting was
previously so deeply hidden that most are unaware of how to
change it. (And previous discussion about changing the canvas
setting to hide partial labels deemed this default undesirable
for the canvas, where showing even a small part of a label
on the map border can help identify what sits just on/off
the edges of the map)
This controls how close labels are permitted to the edges of the map
item. The labeling engine will then try other candidate positions
in order to avoid placing labels within this margin.
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.
