Some optimizations of the color print preview.

src/libslic3r/GCode/PreviewData.cpp

@@ -479,16 +479,13 @@ GCodePreviewData::LegendItemsList GCodePreviewData::get_legend_items(const std::
         }
     case Extrusion::ColorPrint:
         {
-            const size_t color_cnt = tool_colors.size()/4;
+            const int color_cnt = (int)tool_colors.size()/4;
 
-            const auto color_print_cnt = cp_values.size();
+            const auto color_print_cnt = (int)cp_values.size();
-            for (size_t i = color_print_cnt; i >= 0 ; --i)
+            for (int i = color_print_cnt; i >= 0 ; --i)
             {
-                size_t val = i;
-                while (val >= color_cnt)
-                    val -= color_cnt;
                 GCodePreviewData::Color color;
-                ::memcpy((void*)color.rgba, (const void*)(tool_colors.data() + val * 4), 4 * sizeof(float));
+                ::memcpy((void*)color.rgba, (const void*)(tool_colors.data() + (i % color_cnt) * 4), 4 * sizeof(float));
                 
                 if (color_print_cnt == 0) {
                     items.emplace_back(Slic3r::I18N::translate(L("Default print color")), color);

src/slic3r/GUI/GLCanvas3D.cpp

@@ -7288,31 +7288,15 @@ void GLCanvas3D::_load_print_object_toolpaths(const PrintObject& print_object, c
         const float*                 color_tool(size_t tool) const { return tool_colors->data() + tool * 4; }
         int                          volume_idx(int extruder, int feature) const
         {
-            return this->color_by_tool() ? std::min<int>(this->number_tools() - 1, std::max<int>(extruder - 1, 0)) : feature;
+            return this->color_by_color_print() ? 0 : this->color_by_tool() ? std::min<int>(this->number_tools() - 1, std::max<int>(extruder - 1, 0)) : feature;
         }
 
         // For coloring by a color_print(M600), return a parsed color.
         bool                         color_by_color_print() const { return color_print_values!=nullptr; }
         const float*                 color_print_by_layer_idx(const size_t layer_idx) const
         {
-            double z = layers[layer_idx]->print_z;
+            auto it = std::lower_bound(color_print_values->begin(), color_print_values->end(), layers[layer_idx]->print_z - EPSILON);
-            size_t layer = 0;
+            return color_tool((it - color_print_values->begin()) % number_tools());
-            const size_t clr_change_cnt = color_print_values->size();
-            for (size_t i = 0; i < clr_change_cnt; i++)
-            {
-                if (z < (*color_print_values)[i]-EPSILON) {
-                    layer = i;
-                    break;
-                }
-                if (layer == 0 && i == clr_change_cnt - 1)
-                    layer = clr_change_cnt;
-            }
-
-            const size_t clr_cnt = number_tools();
-            while (layer >= clr_cnt)
-                layer -= clr_cnt;
-
-            return color_tool(layer);
         }
     } ctxt;
 

src/slic3r/GUI/GUI_Preview.cpp

@@ -737,9 +737,12 @@ void Preview::load_print_as_fff()
     if (m_gcode_preview_data->extrusion.view_type == GCodePreviewData::Extrusion::ColorPrint)
     {
         colors = GCodePreviewData::ColorPrintColors();
-            
+        if (! gcode_preview_data_valid) {
-        const auto& config = wxGetApp().preset_bundle->full_config();
+            //FIXME accessing full_config() is pretty expensive.
-        color_print_values = config.option<ConfigOptionFloats>("colorprint_heights")->values;
+            // Only initialize color_print_values for the initial preview, not for the full preview where the color_print_values is extracted from the G-code.
+            const auto& config = wxGetApp().preset_bundle->full_config();
+            color_print_values = config.option<ConfigOptionFloats>("colorprint_heights")->values;
+        }
     }
     else if (gcode_preview_data_valid || (m_gcode_preview_data->extrusion.view_type == GCodePreviewData::Extrusion::Tool) )
     {
@@ -758,10 +761,9 @@ void Preview::load_print_as_fff()
                     color = "#FFFFFF";
             }
 
-            colors.push_back(color);
+            colors.emplace_back(color);
         }
-        if (!color_print_values.empty())
+        color_print_values.clear();
-            color_print_values.clear();
     }
 
     if (IsShown())