Add elephant foot compensation to SLA print

Work in progress


Convert efc input to the right scaling


Apply EFC on the slice index to make it visible in the preview.

src/libslic3r/PrintConfig.cpp

@@ -2442,6 +2442,16 @@ void PrintConfigDef::init_sla_params()
                       "to the sign of the correction.");
     def->mode = comExpert;
     def->set_default_value(new ConfigOptionFloat(0.0));
+    
+    def = this->add("elefant_foot_compensation", coFloat);
+    def->label = L("Elephant foot compensation");
+    def->category = L("Advanced");
+    def->tooltip = L("The first layer will be shrunk in the XY plane by the configured value "
+                     "to compensate for the 1st layer squish aka an Elephant Foot effect.");
+    def->sidetext = L("mm");
+    def->min = 0;
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionFloat(0.2));
 
     def = this->add("gamma_correction", coFloat);
     def->label = L("Printer gamma correction");