Part 3.1: refactor BeltTransform pipeline

add BeltGCodeWriter

add BeltGCode

consolidate changes into shared classes for BeltGcode

src/libslic3r/BeltGCodeWriter.hpp

@@ -0,0 +1,50 @@
+#pragma once
+
+#include "GCodeWriter.hpp"
+#include "GCode/BeltBackTransform.hpp"
+
+namespace Slic3r {
+
+// Belt-printer-specific GCode writer.
+//
+// Inherits from GCodeWriter and overrides movement methods to apply
+// coordinate transformation (back-transform, axis remap, origin snap)
+// and emit coupled XYZ moves (Y and Z are coupled due to belt tilt).
+class BeltGCodeWriter : public GCodeWriter
+{
+public:
+    BeltGCodeWriter() : GCodeWriter() {}
+
+    // Belt configuration
+    void set_belt_angle(double angle_deg);
+    bool is_belt_printer() const { return m_belt_angle_rad != 0.; }
+    void set_axis_remap(int rx, int ry, int rz);
+    void set_build_volume_max(const Vec3d &max);
+    void set_belt_back_transform(const PrintConfig &config);
+    void set_origin_snap(int axis, bool enable, double offset, double bbox_min);
+    Vec3d to_machine_coords(const Vec3d &pos) const;
+
+    // Overridden movement methods
+    std::string travel_to_xy(const Vec2d &point, const std::string &comment = std::string()) override;
+    std::string travel_to_xyz(const Vec3d &point, const std::string &comment = std::string(), bool force_z = false) override;
+    std::string extrude_to_xy(const Vec2d &point, double dE, const std::string &comment = std::string(), bool force_no_extrusion = false) override;
+    std::string extrude_to_xyz(const Vec3d &point, double dE, const std::string &comment = std::string(), bool force_no_extrusion = false) override;
+    std::string lazy_lift(LiftType lift_type = LiftType::NormalLift, bool spiral_vase = false) override;
+    std::string eager_lift(const LiftType type) override;
+
+protected:
+    std::string _travel_to_z(double z, const std::string &comment) override;
+
+private:
+    double          m_belt_angle_rad = 0.;
+    int             m_remap_x = 0;
+    int             m_remap_y = 1;
+    int             m_remap_z = 2;
+    Vec3d           m_build_vol_max = Vec3d::Zero();
+    BeltBackTransform m_belt_back_transform;
+    bool            m_origin_snap[3]     = {false, false, false};
+    double          m_origin_offset[3]   = {0., 0., 0.};
+    double          m_origin_bbox_min[3] = {0., 0., 0.};
+};
+
+} // namespace Slic3r