Add button to toggle train purchase window dual pane mode

src/build_vehicle_gui.cpp

@@ -61,6 +61,9 @@ static constexpr NWidgetPart _nested_build_vehicle_widgets[] = {
 	NWidget(NWID_HORIZONTAL),
 		NWidget(WWT_CLOSEBOX, COLOUR_GREY),
 		NWidget(WWT_CAPTION, COLOUR_GREY, WID_BV_CAPTION), SetDataTip(STR_JUST_STRING, STR_TOOLTIP_WINDOW_TITLE_DRAG_THIS), SetTextStyle(TC_WHITE),
+		NWidget(NWID_SELECTION, INVALID_COLOUR, WID_BV_TOGGLE_DUAL_PANE_SEL),
+			NWidget(WWT_IMGBTN, COLOUR_GREY, WID_BV_TOGGLE_DUAL_PANE), SetDataTip(SPR_LARGE_SMALL_WINDOW, STR_BUY_VEHICLE_TRAIN_TOGGLE_DUAL_PANE_TOOLTIP),
+		EndContainer(),
 		NWidget(WWT_SHADEBOX, COLOUR_GREY),
 		NWidget(WWT_DEFSIZEBOX, COLOUR_GREY),
 		NWidget(WWT_STICKYBOX, COLOUR_GREY),
@@ -101,6 +104,7 @@ static constexpr NWidgetPart _nested_build_vehicle_widgets_train_advanced[] = {
 	NWidget(NWID_HORIZONTAL),
 		NWidget(WWT_CLOSEBOX, COLOUR_GREY),
 		NWidget(WWT_CAPTION, COLOUR_GREY, WID_BV_CAPTION), SetDataTip(STR_JUST_STRING, STR_TOOLTIP_WINDOW_TITLE_DRAG_THIS), SetTextStyle(TC_WHITE),
+		NWidget(WWT_IMGBTN, COLOUR_GREY, WID_BV_TOGGLE_DUAL_PANE), SetDataTip(SPR_LARGE_SMALL_WINDOW, STR_BUY_VEHICLE_TRAIN_TOGGLE_DUAL_PANE_TOOLTIP),
 		NWidget(WWT_SHADEBOX, COLOUR_GREY),
 		NWidget(WWT_DEFSIZEBOX, COLOUR_GREY),
 		NWidget(WWT_STICKYBOX, COLOUR_GREY),
@@ -1393,6 +1397,7 @@ enum BuildVehicleHotkeys {
 
 struct BuildVehicleWindowBase : Window {
 	VehicleType vehicle_type;                   ///< Type of vehicles shown in the window.
+	TileIndex tile;                             ///< Original tile.
 	bool virtual_train_mode;                    ///< Are we building a virtual train?
 	Train **virtual_train_out;                  ///< Virtual train ptr
 	bool listview_mode;                         ///< If set, only display the available vehicles and do not show a 'build' button.
@@ -1400,6 +1405,7 @@ struct BuildVehicleWindowBase : Window {
 	BuildVehicleWindowBase(WindowDesc *desc, TileIndex tile, VehicleType type, Train **virtual_train_out) : Window(desc)
 	{
 		this->vehicle_type = type;
+		this->tile = tile;
 		this->window_number = tile == INVALID_TILE ? (int)type : tile;
 		this->virtual_train_out = virtual_train_out;
 		this->virtual_train_mode = (virtual_train_out != nullptr);
@@ -1505,6 +1511,18 @@ struct BuildVehicleWindowBase : Window {
 		te = {};
 		te.FillDefaultCapacities(e);
 	}
+
+	void ChangeDualPaneMode(bool new_value)
+	{
+		_settings_client.gui.dual_pane_train_purchase_window = new_value;
+		SetWindowDirty(WC_GAME_OPTIONS, WN_GAME_OPTIONS_GAME_SETTINGS);
+
+		if (this->virtual_train_out != nullptr) {
+			ShowTemplateTrainBuildVehicleWindow(this->virtual_train_out);
+		} else {
+			ShowBuildVehicleWindow(this->tile, this->vehicle_type);
+		}
+	}
 };
 
 /**
@@ -1625,6 +1643,8 @@ struct BuildVehicleWindow : BuildVehicleWindowBase {
 
 		this->details_height = ((this->vehicle_type == VEH_TRAIN) ? 10 : 9);
 
+		this->GetWidget<NWidgetStacked>(WID_BV_TOGGLE_DUAL_PANE_SEL)->SetDisplayedPlane((this->vehicle_type == VEH_TRAIN) ? 0 : SZSP_NONE);
+
 		this->FinishInitNested(this->window_number);
 
 		this->querystrings[WID_BV_FILTER] = &this->vehicle_editbox;
@@ -2054,6 +2074,11 @@ struct BuildVehicleWindow : BuildVehicleWindowBase {
 				}
 				break;
 			}
+
+			case WID_BV_TOGGLE_DUAL_PANE: {
+				this->ChangeDualPaneMode(true);
+				break;
+			}
 		}
 	}
 
@@ -2788,6 +2813,10 @@ struct BuildVehicleWindowTrainAdvanced final : BuildVehicleWindowBase {
 		}
 
 		switch (widget) {
+			case WID_BV_TOGGLE_DUAL_PANE: {
+				this->ChangeDualPaneMode(false);
+				break;
+			}
 
 			/* Locomotives */
 

src/lang/extra/english.txt

@@ -1574,6 +1574,7 @@ STR_BUY_VEHICLE_TRAIN_RENAME_LOCOMOTIVE_BUTTON                  :{BLACK}Rename L
 STR_BUY_VEHICLE_TRAIN_RENAME_WAGON_BUTTON                       :{BLACK}Rename Wagon
 STR_BUY_VEHICLE_TRAIN_RENAME_LOCOMOTIVE_TOOLTIP                 :{BLACK}Rename locomotive or power car
 STR_BUY_VEHICLE_TRAIN_RENAME_WAGON_TOOLTIP                      :{BLACK}Rename wagon
+STR_BUY_VEHICLE_TRAIN_TOGGLE_DUAL_PANE_TOOLTIP                  :{BLACK}Toggle separate locomotives and wagons
 
 STR_QUERY_RENAME_TRAIN_TYPE_LOCOMOTIVE_CAPTION                  :{WHITE}Rename locomotive type
 STR_QUERY_RENAME_TRAIN_TYPE_WAGON_CAPTION                       :{WHITE}Rename wagon type

src/tbtr_template_gui_create.cpp

@@ -105,8 +105,6 @@ static WindowDesc _template_create_window_desc(__FILE__, __LINE__,
 	std::begin(_widgets), std::end(_widgets)
 );
 
-void ShowTemplateTrainBuildVehicleWindow(Train **virtual_train);
-
 static void TrainDepotMoveVehicle(const Vehicle *wagon, VehicleID sel, const Vehicle *head)
 {
 	const Vehicle *v = Vehicle::Get(sel);

src/vehicle_gui.h

@@ -57,6 +57,7 @@ void DrawShipImage(const Vehicle *v, const Rect &r, VehicleID selection, EngineI
 void DrawAircraftImage(const Vehicle *v, const Rect &r, VehicleID selection, EngineImageType image_type);
 
 void ShowBuildVehicleWindow(TileIndex tile, VehicleType type);
+void ShowTemplateTrainBuildVehicleWindow(Train **virtual_train);
 
 uint ShowRefitOptionsList(int left, int right, int y, EngineID engine);
 StringID GetCargoSubtypeText(const Vehicle *v);

src/widgets/build_vehicle_widget.h

@@ -25,6 +25,8 @@ enum BuildVehicleWidgets : WidgetID {
 	WID_BV_SHOW_HIDE,                 ///< Button to hide or show the selected engine.
 	WID_BV_BUILD_SEL,                 ///< Build button.
 	WID_BV_RENAME,                    ///< Rename button.
+	WID_BV_TOGGLE_DUAL_PANE,          ///< Toggle dual pane windows.
+	WID_BV_TOGGLE_DUAL_PANE_SEL,      ///< Selection for WID_BV_TOGGLE_DUAL_PANE.
 
 	WID_BV_CAPTION_LOCO,                   ///< Caption of locomotive half of the window.
 	WID_BV_SORT_ASCENDING_DESCENDING_LOCO, ///< Sort direction.