1) Removed the already commented-out scaling / unscaling when doing
"safe offsetting"
2) Removed some of the "safe offsetting" at calls where it never was used.
3) Reworked Clipper & ClipperUtils to pass Polygons / ExPolygons / Surfaces
as input parameters without conversion to ClipperLib::Paths. This
should save a lot of memory allocation and copying.
4) Reworked conversions from ClipperLib::Paths & PolyTree to Polygons /
ExPolygons to use the move operator to avoid many unnecessary allocations.
5) Reworked some "union with safe ofsetting" to "offset_ex", which should
be cheaper.
Serialization and deserialization in TriangleSelector were extended to support up to 16 materials (3 unused states left for possible later extension). These changes also affect the encoding of data from custom supports and seams, but it is backward compatible with the previous encoding. And for custom supports and seams, it is produced exactly the same data encoding as before.
1) Using boost::preprocessor to reduce code duplicities when defining
new configuration values.
2) Implemented static hash() and operator== on StaticPrintConfig derived
classes to support hash tables of instances thereof.
the code more readable and to highlight where PrintObject::region_volumes
are actually set and consumed.
2) Replaced Slic3r::clamp() with std::clamp(). They differ in the order
of their parameters, thus hopefully no new bugs were introduced.
3) Some refactoring of MultiMaterialSegmentation for efficiency.
Thus the first_layer_height is no more object specific. That makes
a lot of sense due to the brim calculation being performed over
all layers at once and due to future merging of supports of
different objects at first layer.
2) Because now first_layer_height is print specific, the relative
first layer height derived from the object layer height was partially
disabled: First the relative first layer height is converted to
an absolute value when importing config, second the side text
was changed from "mm or %" to "mm". Still the UI allows entering %.
Both changes may be controversial, let's wait for user feedback.
