Feature: Add "All" filter to build-picker show types from all classes.

Toggling the "All" filter causes the class selection to be ignored, so
that items from all classes can be displayed together. The class text
filter is still applied.

This makes it easier to search amongst types for a feature.

src/lang/english.txt

@@ -2797,6 +2797,9 @@ STR_STATION_BUILD_PLATFORM_LENGTH_TOOLTIP                       :{BLACK}Select l
 STR_STATION_BUILD_DRAG_DROP                                     :{BLACK}Drag & Drop
 STR_STATION_BUILD_DRAG_DROP_TOOLTIP                             :{BLACK}Build a station using drag & drop
 
+STR_PICKER_MODE_ALL                                             :All
+STR_PICKER_MODE_ALL_TOOLTIP                                     :Toggle showing items from all classes
+
 STR_PICKER_STATION_CLASS_TOOLTIP                                :Select a station class to display
 STR_PICKER_STATION_TYPE_TOOLTIP                                 :Select a station type to build. Ctrl+Click to add or remove in saved items
 STR_PICKER_WAYPOINT_CLASS_TOOLTIP                               :Select a waypoint class to display

src/picker_gui.cpp

@@ -107,6 +107,8 @@ void PickerWindow::ConstructWindow()
 	this->classes.SetFilterFuncs(_class_filter_funcs);
 
 	if (this->has_type_picker) {
+		SetWidgetDisabledState(WID_PW_MODE_ALL, !this->callbacks.HasClassChoice());
+
 		this->GetWidget<NWidgetCore>(WID_PW_TYPE_ITEM)->tool_tip = this->callbacks.GetTypeTooltip();
 
 		auto *matrix = this->GetWidget<NWidgetMatrix>(WID_PW_TYPE_MATRIX);
@@ -228,7 +230,9 @@ void PickerWindow::OnClick(Point pt, WidgetID widget, int)
 			auto it = vscroll->GetScrolledItemFromWidget(this->classes, pt.y, this, WID_PW_CLASS_LIST);
 			if (it == this->classes.end()) return;
 
-			if (this->callbacks.GetSelectedClass() != *it) {
+			if (this->callbacks.GetSelectedClass() != *it || HasBit(this->callbacks.mode, PFM_ALL)) {
+				ClrBit(this->callbacks.mode, PFM_ALL); // Disable showing all.
+				SetWidgetLoweredState(WID_PW_MODE_ALL, false);
 				this->callbacks.SetSelectedClass(*it);
 				this->InvalidateData(PFI_TYPE | PFI_POSITION | PFI_VALIDATE);
 			}
@@ -237,6 +241,12 @@ void PickerWindow::OnClick(Point pt, WidgetID widget, int)
 			break;
 		}
 
+		case WID_PW_MODE_ALL:
+			ToggleBit(this->callbacks.mode, widget - WID_PW_MODE_ALL);
+			SetWidgetLoweredState(widget, HasBit(this->callbacks.mode, widget - WID_PW_MODE_ALL));
+			this->InvalidateData(PFI_TYPE | PFI_POSITION);
+			break;
+
 		/* Type Picker */
 		case WID_PW_TYPE_ITEM: {
 			int sel = this->GetWidget<NWidgetBase>(widget)->GetParentWidget<NWidgetMatrix>()->GetCurrentElement();
@@ -268,6 +278,10 @@ void PickerWindow::OnInvalidateData(int data, bool gui_scope)
 	this->BuildPickerTypeList();
 	if ((data & PFI_VALIDATE) != 0) this->EnsureSelectedTypeIsValid();
 	if ((data & PFI_POSITION) != 0) this->EnsureSelectedTypeIsVisible();
+
+	if (this->has_type_picker) {
+		SetWidgetLoweredState(WID_PW_MODE_ALL, HasBit(this->callbacks.mode, PFM_ALL));
+	}
 }
 
 EventState PickerWindow::OnHotkey(int hotkey)
@@ -358,9 +372,23 @@ void PickerWindow::BuildPickerTypeList()
 	if (!this->types.NeedRebuild()) return;
 
 	this->types.clear();
+	bool show_all = HasBit(this->callbacks.mode, PFM_ALL);
 	int cls_id = this->callbacks.GetSelectedClass();
 
-	{
+	if (show_all) {
+		/* Reserve enough space for everything. */
+		int total = 0;
+		for (int class_index : this->classes) total += this->callbacks.GetTypeCount(class_index);
+		this->types.reserve(total);
+		/* Add types in all classes. */
+		for (int class_index : this->classes) {
+			int count = this->callbacks.GetTypeCount(class_index);
+			for (int i = 0; i < count; i++) {
+				if (this->callbacks.GetTypeName(class_index, i) == INVALID_STRING_ID) continue;
+				this->types.emplace_back(this->callbacks.GetPickerItem(class_index, i));
+			}
+		}
+	} else {
 		/* Add types in only the selected class. */
 		if (cls_id >= 0 && cls_id < this->callbacks.GetClassCount()) {
 			int count = this->callbacks.GetTypeCount(cls_id);
@@ -442,6 +470,9 @@ std::unique_ptr<NWidgetBase> MakePickerTypeWidgets()
 				NWidget(WWT_PANEL, COLOUR_DARK_GREEN),
 					NWidget(WWT_EDITBOX, COLOUR_DARK_GREEN, WID_PW_TYPE_FILTER), SetPadding(2), SetResize(1, 0), SetFill(1, 0), SetDataTip(STR_LIST_FILTER_OSKTITLE, STR_LIST_FILTER_TOOLTIP),
 				EndContainer(),
+				NWidget(NWID_HORIZONTAL, NC_EQUALSIZE),
+					NWidget(WWT_TEXTBTN, COLOUR_DARK_GREEN, WID_PW_MODE_ALL), SetFill(1, 0), SetResize(1, 0), SetDataTip(STR_PICKER_MODE_ALL, STR_PICKER_MODE_ALL_TOOLTIP),
+				EndContainer(),
 				NWidget(NWID_HORIZONTAL),
 					NWidget(WWT_PANEL, COLOUR_DARK_GREEN), SetScrollbar(WID_PW_TYPE_SCROLL),
 						NWidget(NWID_MATRIX, COLOUR_DARK_GREEN, WID_PW_TYPE_MATRIX), SetPIP(0, 2, 0), SetPadding(WidgetDimensions::unscaled.picker),

src/picker_gui.h

@@ -79,6 +79,8 @@ class PickerCallbacks {
 
 	Listing type_last_sorting = { false, 0 }; ///< Default sorting of #PickerTypeList.
 	Filtering type_last_filtering = { false, 0 }; ///< Default filtering of #PickerTypeList.
+
+	uint8_t mode = 0; ///< Bitmask of \c PickerFilterModes.
 };
 
 /** Helper for PickerCallbacks when the class system is based on NewGRFClass. */
@@ -115,6 +117,10 @@ using PickerTypeList = GUIList<PickerItem, std::nullptr_t, PickerFilterData &>;
 
 class PickerWindow : public PickerWindowBase {
 public:
+	enum PickerFilterModes {
+		PFM_ALL = 0, ///< Show all classes.
+	};
+
 	enum PickerFilterInvalidation {
 		PFI_CLASS = 1U << 0, ///< Refresh the class list.
 		PFI_TYPE = 1U << 1, ///< Refresh the type list.

src/widgets/picker_widget.h

@@ -21,6 +21,7 @@ enum PickerClassWindowWidgets : WidgetID {
 
 	WID_PW_TYPE_SEL, ///< Stack to hide the type picker.
 	WID_PW_TYPE_FILTER, ///< Text filter.
+	WID_PW_MODE_ALL, ///< Toggle "Show all" filter mode.
 	WID_PW_TYPE_MATRIX, ///< Matrix with items.
 	WID_PW_TYPE_ITEM, ///< A single item.
 	WID_PW_TYPE_SCROLL, ///< Scrollbar for the matrix.