From 9fe42ecbdc7927aec643d7a9449b42ffbb7a2af8 Mon Sep 17 00:00:00 2001
From: enricoturri1966 <enricoturri@seznam.cz>
Date: Tue, 18 Jul 2023 15:23:40 +0200
Subject: [PATCH] Method GCodeProcessor::process_G2_G3() modified to process
 lines G2/G3 R

---
 src/libslic3r/GCode/GCodeProcessor.cpp | 44 +++++++++++++++++++-------
 1 file changed, 32 insertions(+), 12 deletions(-)

diff --git a/src/libslic3r/GCode/GCodeProcessor.cpp b/src/libslic3r/GCode/GCodeProcessor.cpp
index c8485a319c..e654d88f93 100644
--- a/src/libslic3r/GCode/GCodeProcessor.cpp
+++ b/src/libslic3r/GCode/GCodeProcessor.cpp
@@ -6,6 +6,7 @@
 #include "libslic3r/I18N.hpp"
 #include "libslic3r/GCode/GCodeWriter.hpp"
 #include "libslic3r/I18N.hpp"
+#include "libslic3r/Geometry/ArcWelder.hpp"
 #include "GCodeProcessor.hpp"
 
 #include <boost/algorithm/string/case_conv.hpp>
@@ -2698,13 +2699,39 @@ void GCodeProcessor::process_G1(const std::array<std::optional<double>, 4>& axes
 
 void GCodeProcessor::process_G2_G3(const GCodeReader::GCodeLine& line, bool clockwise)
 {
-    if (!line.has('I') || !line.has('J'))
+    enum class EFitting { None, IJ, R };
+    const EFitting fitting = line.has('R') ? EFitting::R : (line.has('I') && line.has('J')) ? EFitting::IJ : EFitting::None;
+
+    if (fitting == EFitting::None)
         return;
 
+    const float filament_diameter = (static_cast<size_t>(m_extruder_id) < m_result.filament_diameters.size()) ? m_result.filament_diameters[m_extruder_id] : m_result.filament_diameters.back();
+    const float filament_radius = 0.5f * filament_diameter;
+    const float area_filament_cross_section = static_cast<float>(M_PI) * sqr(filament_radius);
+
+    AxisCoords end_position = m_start_position;
+    for (unsigned char a = X; a <= E; ++a) {
+        end_position[a] = extract_absolute_position_on_axis((Axis)a, line, double(area_filament_cross_section));
+    }
+
     // relative center
     Vec3f rel_center = Vec3f::Zero();
-    if (!line.has_value('I', rel_center.x()) || !line.has_value('J', rel_center.y()))
-        return;
+    double radius = 0.0;
+    if (fitting == EFitting::R) {
+        float r;
+        if (!line.has_value('R', r) || r == 0.0f)
+            return;
+        radius = (double)std::abs(r);
+        const Vec2f start_pos((float)m_start_position[X], (float)m_start_position[Y]);
+        const Vec2f end_pos((float)end_position[X], (float)end_position[Y]);
+        const Vec2f c = Geometry::ArcWelder::arc_center(start_pos, end_pos, r, !clockwise);
+        rel_center.x() = c.x() - m_start_position[X];
+        rel_center.y() = c.y() - m_start_position[Y];
+    }
+    else {
+        if (!line.has_value('I', rel_center.x()) || !line.has_value('J', rel_center.y()))
+            return;
+    }
 
     // scale center, if needed
     if (m_units == EUnits::Inches)
@@ -2740,15 +2767,6 @@ void GCodeProcessor::process_G2_G3(const GCodeReader::GCodeLine& line, bool cloc
     // arc center
     arc.center = arc.start + rel_center.cast<double>();
 
-    const float filament_diameter = (static_cast<size_t>(m_extruder_id) < m_result.filament_diameters.size()) ? m_result.filament_diameters[m_extruder_id] : m_result.filament_diameters.back();
-    const float filament_radius = 0.5f * filament_diameter;
-    const float area_filament_cross_section = static_cast<float>(M_PI) * sqr(filament_radius);
-
-    AxisCoords end_position = m_start_position;
-    for (unsigned char a = X; a <= E; ++a) {
-        end_position[a] = extract_absolute_position_on_axis((Axis)a, line, double(area_filament_cross_section));
-    }
-
     // arc end endpoint
     arc.end = Vec3d(end_position[X], end_position[Y], end_position[Z]);
 
@@ -2757,6 +2775,8 @@ void GCodeProcessor::process_G2_G3(const GCodeReader::GCodeLine& line, bool cloc
         // what to do ???
     }
 
+    assert(fitting != EFitting::R || std::abs(radius - arc.start_radius()) < EPSILON);
+
     // updates feedrate from line
     std::optional<float> feedrate;
     if (line.has_f())