1 files changed, 120 insertions, 0 deletions
diff --git a/xs/src/libslic3r/Flow.cpp b/xs/src/libslic3r/Flow.cpp
new file mode 100644
index 000000000..1592e0c35
--- /dev/null
+++ b/xs/src/libslic3r/Flow.cpp
@@ -0,0 +1,120 @@
+#include "Flow.hpp"
+#include <cmath>
+
+namespace Slic3r {
+
+/* This constructor builds a Flow object from an extrusion width config setting
+   and other context properties. */
+Flow
+Flow::new_from_config_width(FlowRole role, const ConfigOptionFloatOrPercent &width, float nozzle_diameter, float height, float bridge_flow_ratio) {
+    // we need layer height unless it's a bridge
+    if (height <= 0 && bridge_flow_ratio == 0) CONFESS("Invalid flow height supplied to new_from_config_width()");
+    
+    float w;
+    if (bridge_flow_ratio > 0) {
+        // if bridge flow was requested, calculate bridge width
+        w = Flow::_bridge_width(nozzle_diameter, bridge_flow_ratio);
+    } else if (!width.percent && width.value == 0) {
+        // if user left option to 0, calculate a sane default width
+        w = Flow::_auto_width(role, nozzle_diameter, height);
+    } else {
+        // if user set a manual value, use it
+        w = width.get_abs_value(height);
+    }
+    
+    return Flow(w, height, nozzle_diameter, bridge_flow_ratio > 0);
+}
+
+/* This constructor builds a Flow object from a given centerline spacing. */
+Flow
+Flow::new_from_spacing(float spacing, float nozzle_diameter, float height, bool bridge) {
+    // we need layer height unless it's a bridge
+    if (height <= 0 && !bridge) CONFESS("Invalid flow height supplied to new_from_spacing()");
+
+    float w = Flow::_width_from_spacing(spacing, nozzle_diameter, height, bridge);
+    return Flow(w, height, nozzle_diameter, bridge);
+}
+
+/* This method returns the centerline spacing between two adjacent extrusions 
+   having the same extrusion width (and other properties). */
+float
+Flow::spacing() const {
+    if (this->bridge) {
+        return this->width + BRIDGE_EXTRA_SPACING;
+    }
+    
+    // rectangle with semicircles at the ends
+    float min_flow_spacing = this->width - this->height * (1 - PI/4.0);
+    return this->width - OVERLAP_FACTOR * (this->width - min_flow_spacing);
+}
+
+/* This method returns the centerline spacing between an extrusion using this
+   flow and another one using another flow.
+   this->spacing(other) shall return the same value as other.spacing(*this) */
+float
+Flow::spacing(const Flow &other) const {
+    assert(this->height == other.height);
+    assert(this->bridge == other.bridge);
+    
+    if (this->bridge) {
+        return this->width/2 + other.width/2 + BRIDGE_EXTRA_SPACING;
+    }
+    
+    return this->spacing()/2 + other.spacing()/2;
+}
+
+/* This method returns extrusion volume per head move unit. */
+double
+Flow::mm3_per_mm() const {
+    if (this->bridge) {
+        return (this->width * this->width) * PI/4.0;
+    }
+    
+    // rectangle with semicircles at the ends
+    return this->width * this->height + (this->height*this->height) / 4.0 * (PI-4.0);
+}
+
+/* This static method returns bridge width for a given nozzle diameter. */
+float
+Flow::_bridge_width(float nozzle_diameter, float bridge_flow_ratio) {
+    if (bridge_flow_ratio == 1) return nozzle_diameter;  // optimization to avoid sqrt()
+    return sqrt(bridge_flow_ratio * (nozzle_diameter*nozzle_diameter));
+}
+
+/* This static method returns a sane extrusion width default. */
+float
+Flow::_auto_width(FlowRole role, float nozzle_diameter, float height) {
+    // here we calculate a sane default by matching the flow speed (at the nozzle) and the feed rate
+    // shape: rectangle with semicircles at the ends
+    float width = ((nozzle_diameter*nozzle_diameter) * PI + (height*height) * (4.0 - PI)) / (4.0 * height);
+    
+    float min = nozzle_diameter * 1.05;
+    float max = -1;
+    if (role == frExternalPerimeter || role == frSupportMaterial) {
+        min = max = nozzle_diameter;
+    } else if (role != frInfill) {
+        // do not limit width for sparse infill so that we use full native flow for it
+        max = nozzle_diameter * 1.7;
+    }
+    if (max != -1 && width > max) width = max;
+    if (width < min) width = min;
+    
+    return width;
+}
+
+/* This static method returns the extrusion width value corresponding to the supplied centerline spacing. */
+float
+Flow::_width_from_spacing(float spacing, float nozzle_diameter, float height, bool bridge) {
+    if (bridge) {
+        return spacing - BRIDGE_EXTRA_SPACING;
+    }
+    
+    // rectangle with semicircles at the ends
+    return spacing + OVERLAP_FACTOR * height * (1 - PI/4.0);
+}
+
+#ifdef SLIC3RXS
+REGISTER_CLASS(Flow, "Flow");
+#endif
+
+}