The two new config keys define a minimum vertical shell thickness.
The top shell thickness is calculated as a maximum of sum over
top_solid_layers * layer heights and top_solid_min_thickness,
the bottom shell thickness is calculated as a maximum of sum over
bottom_solid_layers * layer heights and bottom_solid_min_thickness.
The results of the formula above are shown at the Print parameter page
below the two new values to hint the user about the interaction
of the old versus new config values.
top_solid_min_thickness has no meaning if top_solid_layers is zero,
bottom_solid_min_thickness has no meaning if bottom_solid_layers is zero.
If the Elephant foot compensation is applied to the 1st object's layer,
the uncompensated 1st object's slice is newly used for calculation
of bridges, overhans, skirt, brim, raft and supports.
Layer::slices were renamed to Layer::lslices to simplify reading
of the code, to differentiate from LayerRegion::slices.
Layer newly remembers bounding boxes of slices,
the bounding boxes are used by G-code generator & newly the support
generator.
Slices are stored as ExPolygons, not ExPolygonCollection.
Fix of "Bridging infill not connecting with infill set to 0%" #1301
Top, bottom and bridging areas are extended into infill as long
as the infill is not zero. If the infill is zero,
top, bottom and bridging areas wound not expand into these "void" areas.
With this commit, the top, bottom and bridging areas are allowed to expand
into the "void" areas as long as these "void" areas are supported below
with perimeters or some other non-empty infill, and slightly beyond
these supporting areas into the voids (currently hard coded to 1mm).
