ENH: new seam strategy from prusa2.5

As title. Thanks @Prusa

Signed-off-by: salt.wei <salt.wei@bambulab.com>
Change-Id: I2fa177e27ac53211952ea9b6c62e98182b8f05ce

src/libslic3r/ShortEdgeCollapse.hpp

@@ -0,0 +1,16 @@
+#ifndef SRC_LIBSLIC3R_SHORTEDGECOLLAPSE_HPP_
+#define SRC_LIBSLIC3R_SHORTEDGECOLLAPSE_HPP_
+
+#include "libslic3r/TriangleMesh.hpp"
+
+namespace Slic3r{
+
+// Decimates the model by collapsing short edges. It starts with very small edges and gradually increases the collapsible length,
+// until the target triangle count is reached (the algorithm will certainly undershoot the target count, result will have less triangles than target count)
+//  The algorithm does not check for triangle flipping, disconnections, self intersections or any other degeneration that can appear during mesh processing.
+void its_short_edge_collpase(indexed_triangle_set &mesh, size_t target_triangle_count);
+
+}
+
+
+#endif /* SRC_LIBSLIC3R_SHORTEDGECOLLAPSE_HPP_ */