From 73a912d76d6513a675742967f491eb53af6260ce Mon Sep 17 00:00:00 2001
From: igiannakas <ioannis@my-spot.co.uk>
Date: Wed, 6 Nov 2024 18:19:08 +0000
Subject: [PATCH 1/3] Optimisation: Reduce volume of output gcode commands for
 pressure equalizer

---
 src/libslic3r/GCode/PressureEqualizer.cpp | 23 +++++++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)

diff --git a/src/libslic3r/GCode/PressureEqualizer.cpp b/src/libslic3r/GCode/PressureEqualizer.cpp
index 806ef768e71..c3d54ae81d1 100644
--- a/src/libslic3r/GCode/PressureEqualizer.cpp
+++ b/src/libslic3r/GCode/PressureEqualizer.cpp
@@ -482,11 +482,25 @@ void PressureEqualizer::output_gcode_line(const size_t line_idx)
     if (*comment != ';')
         comment = nullptr;
 
-    // Emit the line with lowered extrusion rates.
+    // get the gcode line length
     float l = line.dist_xyz();
-    if (auto nSegments = size_t(ceil(l / m_max_segment_length)); nSegments == 1) { // Just update this segment.
+    // number of segments this line can be broken down to
+    auto nSegments = size_t(ceil(l / m_max_segment_length));
+    
+    // Orca:
+    // Calculate the absolute difference in volumetric extrusion rate between the start and end point of the line.
+    // Quantize it to 1mm3/min (0.016mm3/sec).
+    int delta_volumetric_rate = std::round(fabs(line.volumetric_extrusion_rate_end - line.volumetric_extrusion_rate_start));
+    
+    // Emit the line with lowered extrusion rates.
+    // Orca:
+    // First, check if the change in volumetric extrusion rate is negligible.
+    // Or if the line size is equal in length with the smallest segment.
+    // If so, then emit the line as a single extrusion, i.e. dont split into segments.
+    if ( nSegments == 1 || delta_volumetric_rate == 0) {
         push_line_to_output(line_idx, line.feedrate() * line.volumetric_correction_avg(), comment);
-    } else {
+    } else // The line needs to be split the line into segments and apply extrusion rate smoothing
+    {
         bool accelerating = line.volumetric_extrusion_rate_start < line.volumetric_extrusion_rate_end;
         // Update the initial and final feed rate values.
         line.pos_start[4] = line.volumetric_extrusion_rate_start * line.pos_end[4] / line.volumetric_extrusion_rate;
@@ -769,7 +783,8 @@ void PressureEqualizer::push_line_to_output(const size_t line_idx, float new_fee
     // Orca: sanity check, 1 mm/s is the minimum feedrate.
     if (new_feedrate < 60)
         new_feedrate = 60;
-    new_feedrate = std::round(new_feedrate);
+    // Quantize speed changes to a minimum of 1mm/sec, to reduce gcode volume for trivial speed changes.
+    new_feedrate = std::round(new_feedrate / 60.0) * 60.0;
     const GCodeLine &line = m_gcode_lines[line_idx];
     if (line_idx > 0 && output_buffer_length > 0) {
         const std::string prev_line_str = std::string(output_buffer.begin() + int(this->output_buffer_prev_length),

From a1811b24b864fb3c274ff013df227fe1422db30b Mon Sep 17 00:00:00 2001
From: igiannakas <ioannis@my-spot.co.uk>
Date: Wed, 6 Nov 2024 19:00:48 +0000
Subject: [PATCH 2/3] Update thresholds

---
 src/libslic3r/GCode/PressureEqualizer.cpp | 4 ++--
 src/libslic3r/PrintConfig.cpp             | 1 +
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/libslic3r/GCode/PressureEqualizer.cpp b/src/libslic3r/GCode/PressureEqualizer.cpp
index c3d54ae81d1..d5ddc50d919 100644
--- a/src/libslic3r/GCode/PressureEqualizer.cpp
+++ b/src/libslic3r/GCode/PressureEqualizer.cpp
@@ -494,10 +494,10 @@ void PressureEqualizer::output_gcode_line(const size_t line_idx)
     
     // Emit the line with lowered extrusion rates.
     // Orca:
-    // First, check if the change in volumetric extrusion rate is negligible.
+    // First, check if the change in volumetric extrusion rate is trivial (less than 10mm3/min -> 0.16mm3/sec (5mm/sec speed for a 0.25 mm nozzle).
     // Or if the line size is equal in length with the smallest segment.
     // If so, then emit the line as a single extrusion, i.e. dont split into segments.
-    if ( nSegments == 1 || delta_volumetric_rate == 0) {
+    if ( nSegments == 1 || delta_volumetric_rate < 10) {
         push_line_to_output(line_idx, line.feedrate() * line.volumetric_correction_avg(), comment);
     } else // The line needs to be split the line into segments and apply extrusion rate smoothing
     {
diff --git a/src/libslic3r/PrintConfig.cpp b/src/libslic3r/PrintConfig.cpp
index b93e7920d31..c62eea9da73 100644
--- a/src/libslic3r/PrintConfig.cpp
+++ b/src/libslic3r/PrintConfig.cpp
@@ -3330,6 +3330,7 @@ void PrintConfigDef::init_fff_params()
     				 "Allowed values: 1-5");
     def->min = 1;
     def->max = 5;
+    def->sidetext = L("mm");
     def->mode = comAdvanced;
     def->set_default_value(new ConfigOptionInt(3));
 

From b2f222dcc2e2170c93fa58b724300b1682585630 Mon Sep 17 00:00:00 2001
From: igiannakas <ioannis@my-spot.co.uk>
Date: Wed, 6 Nov 2024 19:01:26 +0000
Subject: [PATCH 3/3] Update PrintConfig.cpp

---
 src/libslic3r/PrintConfig.cpp | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/libslic3r/PrintConfig.cpp b/src/libslic3r/PrintConfig.cpp
index c62eea9da73..b93e7920d31 100644
--- a/src/libslic3r/PrintConfig.cpp
+++ b/src/libslic3r/PrintConfig.cpp
@@ -3330,7 +3330,6 @@ void PrintConfigDef::init_fff_params()
     				 "Allowed values: 1-5");
     def->min = 1;
     def->max = 5;
-    def->sidetext = L("mm");
     def->mode = comAdvanced;
     def->set_default_value(new ConfigOptionInt(3));