ENH: speed gcode export up again

thanks prusa

Signed-off-by: salt.wei <salt.wei@bambulab.com>
Change-Id: Ifbe5e2ea55b16a7fe281b54ca16c37695c15f5b1

src/libslic3r/GCode/RetractWhenCrossingPerimeters.hpp

@@ -0,0 +1,32 @@
+#ifndef slic3r_RetractWhenCrossingPerimeters_hpp_
+#define slic3r_RetractWhenCrossingPerimeters_hpp_
+
+#include <vector>
+
+#include "../AABBTreeIndirect.hpp"
+
+namespace Slic3r {
+
+// Forward declarations.
+class ExPolygon;
+class Layer;
+class Polyline;
+
+class RetractWhenCrossingPerimeters
+{
+public:
+    bool    travel_inside_internal_regions(const Layer &layer, const Polyline &travel);
+
+private:
+    // Last object layer visited, for which a cache of internal islands was created.
+    const Layer                        *m_layer;
+    // Internal islands only, referencing data owned by m_layer->regions()->surfaces().
+    std::vector<const ExPolygon*>       m_internal_islands;
+    // Search structure over internal islands.
+    using AABBTree = AABBTreeIndirect::Tree<2, coord_t>;
+    AABBTree                            m_aabbtree_internal_islands;
+};
+
+} // namespace Slic3r
+
+#endif // slic3r_RetractWhenCrossingPerimeters_hpp_