Fix issues with 'create alternative tile' button

Fix button sizing for small tile sizes.
Stop button from preventing MMB panning.
Support undo operations for the button.
Hide button when "Paint" mode is active.

editor/plugins/tiles/tile_set_atlas_source_editor.cpp

@@ -971,40 +971,44 @@ void TileSetAtlasSourceEditor::_update_atlas_view() {
 		tile_create_help->set_visible(tools_button_group->get_pressed_button() == tool_setup_atlas_source_button);
 	}
 
-	Vector2i pos;
-	Vector2 texture_region_base_size = tile_set_atlas_source->get_texture_region_size();
-	int texture_region_base_size_min = MIN(texture_region_base_size.x, texture_region_base_size.y);
-	for (int i = 0; i < tile_set_atlas_source->get_tiles_count(); i++) {
-		Vector2i tile_id = tile_set_atlas_source->get_tile_id(i);
-		int alternative_count = tile_set_atlas_source->get_alternative_tiles_count(tile_id);
-		if (alternative_count > 1) {
-			// Compute the right extremity of alternative.
-			int y_increment = 0;
-			pos.x = 0;
-			for (int j = 1; j < alternative_count; j++) {
-				int alternative_id = tile_set_atlas_source->get_alternative_tile_id(tile_id, j);
-				Rect2i rect = tile_atlas_view->get_alternative_tile_rect(tile_id, alternative_id);
-				pos.x = MAX(pos.x, rect.get_end().x);
-				y_increment = MAX(y_increment, rect.size.y);
-			}
-
-			// Create and position the button.
-			Button *button = memnew(Button);
-			button->set_flat(true);
-			button->set_button_icon(get_editor_theme_icon(SNAME("Add")));
-			button->add_theme_style_override(CoreStringName(normal), memnew(StyleBoxEmpty));
-			button->add_theme_style_override(SceneStringName(hover), memnew(StyleBoxEmpty));
-			button->add_theme_style_override("focus", memnew(StyleBoxEmpty));
-			button->add_theme_style_override(SceneStringName(pressed), memnew(StyleBoxEmpty));
-			button->connect(SceneStringName(pressed), callable_mp(tile_set_atlas_source, &TileSetAtlasSource::create_alternative_tile).bind(tile_id, TileSetSource::INVALID_TILE_ALTERNATIVE));
-			button->set_rect(Rect2(Vector2(pos.x, pos.y + (y_increment - texture_region_base_size.y) / 2.0), Vector2(texture_region_base_size_min, texture_region_base_size_min)));
-			button->set_expand_icon(true);
-			alternative_tiles_control->add_child(button);
-
-			pos.y += y_increment;
-		}
-	}
-	tile_atlas_view->set_padding(Side::SIDE_RIGHT, texture_region_base_size_min);
+	if (tools_button_group->get_pressed_button() != tool_paint_button) {
+		Vector2i pos;
+		Vector2 texture_region_base_size = tile_set_atlas_source->get_texture_region_size();
+		int texture_region_base_size_min = MIN(texture_region_base_size.x, texture_region_base_size.y);
+		for (int i = 0; i < tile_set_atlas_source->get_tiles_count(); i++) {
+			Vector2i tile_id = tile_set_atlas_source->get_tile_id(i);
+			int alternative_count = tile_set_atlas_source->get_alternative_tiles_count(tile_id);
+			if (alternative_count > 1) {
+				// Compute the right extremity of alternative.
+				int y_increment = 0;
+				pos.x = 0;
+				for (int j = 1; j < alternative_count; j++) {
+					int alternative_id = tile_set_atlas_source->get_alternative_tile_id(tile_id, j);
+					Rect2i rect = tile_atlas_view->get_alternative_tile_rect(tile_id, alternative_id);
+					pos.x = MAX(pos.x, rect.get_end().x);
+					y_increment = MAX(y_increment, rect.size.y);
+				}
+
+				// Create and position the button.
+				Button *button = memnew(Button);
+				button->set_flat(true);
+				button->set_button_icon(get_editor_theme_icon(SNAME("Add")));
+				button->add_theme_style_override(CoreStringName(normal), memnew(StyleBoxEmpty));
+				button->add_theme_style_override(SceneStringName(hover), memnew(StyleBoxEmpty));
+				button->add_theme_style_override("focus", memnew(StyleBoxEmpty));
+				button->add_theme_style_override(SceneStringName(pressed), memnew(StyleBoxEmpty));
+				button->add_theme_constant_override("align_to_largest_stylebox", false);
+				button->set_mouse_filter(Control::MOUSE_FILTER_PASS);
+				button->connect(SceneStringName(pressed), callable_mp(this, &TileSetAtlasSourceEditor::_tile_alternatives_create_button_pressed).bind(tile_id));
+				button->set_rect(Rect2(Vector2(pos.x, pos.y + (y_increment - texture_region_base_size.y) / 2.0), Vector2(texture_region_base_size_min, texture_region_base_size_min)));
+				button->set_expand_icon(true);
+				alternative_tiles_control->add_child(button);
+
+				pos.y += y_increment;
+			}
+		}
+		tile_atlas_view->set_padding(Side::SIDE_RIGHT, texture_region_base_size_min);
+	}
 
 	// Redraw everything.
 	tile_atlas_control->queue_redraw();
@@ -2009,6 +2013,17 @@ void TileSetAtlasSourceEditor::_tile_alternatives_control_mouse_exited() {
 	alternative_tiles_control_unscaled->queue_redraw();
 }
 
+void TileSetAtlasSourceEditor::_tile_alternatives_create_button_pressed(const Vector2i &p_atlas_coords) {
+	EditorUndoRedoManager *undo_redo = EditorUndoRedoManager::get_singleton();
+
+	// FIXME: Doesn't undo changes to `next_alternative_id` counter.
+	undo_redo->create_action(TTR("Create tile alternatives"));
+	int next_id = tile_set_atlas_source->get_next_alternative_tile_id(p_atlas_coords);
+	undo_redo->add_do_method(tile_set_atlas_source, "create_alternative_tile", p_atlas_coords, next_id);
+	undo_redo->add_undo_method(tile_set_atlas_source, "remove_alternative_tile", p_atlas_coords, next_id);
+	undo_redo->commit_action();
+}
+
 void TileSetAtlasSourceEditor::_tile_alternatives_control_draw() {
 	// Update the hovered alternative tile.
 	if (tools_button_group->get_pressed_button() == tool_select_button) {

editor/plugins/tiles/tile_set_atlas_source_editor.h

@@ -253,6 +253,7 @@ private:
 	PopupMenu *alternative_tile_popup_menu = nullptr;
 	Control *alternative_tiles_control = nullptr;
 	Control *alternative_tiles_control_unscaled = nullptr;
+	void _tile_alternatives_create_button_pressed(const Vector2i &p_atlas_coords);
 	void _tile_alternatives_control_draw();
 	void _tile_alternatives_control_unscaled_draw();
 	void _tile_alternatives_control_mouse_exited();