Splitting out the preset chooser to its own class from Plater for ease of testing purposes.

src/GUI/Plater/PresetChooser.cpp

@@ -0,0 +1,119 @@
+#include "PresetChooser.hpp"
+
+namespace Slic3r { namespace GUI {
+
+PresetChooser::PresetChooser(wxWindow* parent) :
+    wxPanel(parent, wxID_ANY, wxDefaultPosition, wxDefaultSize, wxTAB_TRAVERSAL, "") 
+{
+    for (auto group : { preset_t::Print, preset_t::Material, preset_t::Printer }) {
+        wxString name = "";
+        switch(group) {
+            case preset_t::Print:
+                name << _("Print settings:");
+                break;
+            case preset_t::Material:
+                name << _("Material:");
+                break;
+            case preset_t::Printer:
+                name << _("Printer:");
+                break;
+            default:
+                break;
+        }
+//        auto* text {new wxStaticText(this, wxID_ANY, name, wxDefaultPosition, wxDefaultSize, wxALIGN_RIGHT)};
+//        text->SetFont(ui_settings->small_font());
+
+        auto* choice {new wxBitmapComboBox(this, wxID_ANY, "", wxDefaultPosition, wxDefaultSize, 0, nullptr, wxCB_READONLY)};
+        this->preset_choosers[get_preset(group)].push_back(choice);
+        
+        // setup listener. 
+        // On a combobox event, puts a call to _on_change_combobox() on the evt_idle stack.
+        choice->Bind(wxEVT_COMBOBOX, 
+            [=](wxCommandEvent& e) { 
+                wxTheApp->CallAfter([=]() { this->_on_change_combobox(group, choice);} );
+            });
+    }
+}
+
+void PresetChooser::load(std::array<Presets, preset_types> presets) {
+    for (const auto& group : { preset_t::Print, preset_t::Material, preset_t::Printer }) {
+        auto current_list = presets.at(get_preset(group));
+        if (current_list.size() > 1) {
+            current_list = grep(presets.at(get_preset(group)), [] (const Preset& x) -> bool { return !x.default_preset; });
+        }
+        
+        // populate the chooser
+        for (auto* chooser :  this->preset_choosers[get_preset(group)]) {
+            chooser->Clear();
+            for (auto preset : current_list) {
+                wxBitmap bitmap;
+                switch (group) {
+                    case preset_t::Print:
+                        bitmap = wxBitmap(var("cog.png"), wxBITMAP_TYPE_PNG);
+                        break;
+                    case preset_t::Material: 
+                        if (auto config =  preset.config().lock()) {
+                            if (preset.default_preset || !config->has("filament_colour"))
+                                bitmap = wxBitmap(var("spool.png"), wxBITMAP_TYPE_PNG);
+                        } else { // fall back if for some reason the config is dead.
+                            bitmap = wxBitmap(var("spool.png"), wxBITMAP_TYPE_PNG);
+                        }
+                        break;
+                    case preset_t::Printer: 
+                        bitmap = wxBitmap(var("printer_empty.png"), wxBITMAP_TYPE_PNG);
+                        break;
+                    default: break;
+                }
+                chooser->Append(preset.name, bitmap);
+                __chooser_names[get_preset(group)].push_back(preset.name);
+            }
+        }
+    }
+}
+
+void PresetChooser::_on_change_combobox(preset_t preset, wxBitmapComboBox* choice) {
+    
+    // Prompt for unsaved changes and undo selections if cancelled and return early
+    // Callback to close preset editor tab, close editor tabs, reload presets.
+    wxTheApp->CallAfter([this](){
+
+//        this->_on_select_preset(preset);
+        // reload presets; removes the modified mark
+        this->load();
+    });
+    /*
+    sub _on_change_combobox {
+    my ($self, $group, $choice) = @_;
+    
+    if (0) {
+        # This code is disabled because wxPerl doesn't provide GetCurrentSelection
+        my $current_name = $self->{preset_choosers_names}{$choice}[$choice->GetCurrentSelection];
+        my $current = first { $_->name eq $current_name } @{wxTheApp->presets->{$group}};
+        if (!$current->prompt_unsaved_changes($self)) {
+            # Restore the previous one
+            $choice->SetSelection($choice->GetCurrentSelection);
+            return;
+        }
+    } else {
+        return 0 if !$self->prompt_unsaved_changes;
+    }
+    wxTheApp->CallAfter(sub {
+        # Close the preset editor tab if any
+        if (exists $self->GetFrame->{preset_editor_tabs}{$group}) {
+            my $tabpanel = $self->GetFrame->{tabpanel};
+            $tabpanel->DeletePage($tabpanel->GetPageIndex($self->GetFrame->{preset_editor_tabs}{$group}));
+            delete $self->GetFrame->{preset_editor_tabs}{$group};
+            $tabpanel->SetSelection(0); # without this, a newly created tab will not be selected by wx
+        }
+        
+        $self->_on_select_preset($group);
+        
+        # This will remove the "(modified)" mark from any dirty preset handled here.
+        $self->load_presets;
+    });
+}
+*/
+}
+
+
+}} // Slic3r::GUI

src/GUI/Plater/PresetChooser.hpp

@@ -0,0 +1,45 @@
+#ifndef PRESET_CHOOSER_HPP
+#define PRESET_CHOOSER_HPP
+#include <wx/wxprec.h>
+#ifndef WX_PRECOMP
+    #include <wx/wx.h>
+    #include <wx/panel.h>
+    #include <wx/sizer.h>
+    #include <wx/bmpcbox.h>
+#endif
+
+#include "misc_ui.hpp"
+#include "Preset.hpp"
+#include "GUI.hpp"
+
+namespace Slic3r { namespace GUI {
+
+using Choosers = std::vector<wxBitmapComboBox*>;
+using chooser_name_list = std::vector<wxString>;
+using chooser_name_map = std::array<chooser_name_list, preset_types>;
+
+class PresetChooser : public wxPanel {
+public:
+    PresetChooser(wxWindow* parent);
+
+    std::array<Choosers, preset_types> preset_choosers;
+
+
+    /// Load the presets from the backing store and set up the choosers
+    void load(std::array<Presets, preset_types> presets);
+    
+    /// Call load() with the app's own presets
+    void load() { this->load(SLIC3RAPP->presets); }
+
+    /// Const reference to internal name map (used for testing)
+    const chooser_name_map& _chooser_names() const { return this->__chooser_names; }
+
+private:
+    wxSizer* local_sizer {};
+    void _on_change_combobox(preset_t preset, wxBitmapComboBox* choice);
+    chooser_name_map __chooser_names; 
+
+};
+
+}} // Slic3r::GUI
+#endif // PRESET_CHOOSER_HPP