Guide: Allow to move back and forth in alternates

callbacks.lua

@@ -160,8 +160,8 @@ minetest.register_on_player_receive_fields(function(player, formname, fields)
 				{to_player=player_name, gain = 1.0})
 	end
 
-	-- alternate button
+	-- alternate buttons
-	if not fields.alternate then
+	if not (fields.alternate or fields.alternate_prev) then
 		return
 	end
 	minetest.sound_play("click",
@@ -178,10 +178,18 @@ minetest.register_on_player_receive_fields(function(player, formname, fields)
 	if alternates <= 1 then
 		return
 	end
-	local alternate = unified_inventory.alternate[player_name] + 1
+	local alternate
+	if fields.alternate then
+		alternate = unified_inventory.alternate[player_name] + 1
 		if alternate > alternates then
 			alternate = 1
 		end
+	elseif fields.alternate_prev then
+		alternate = unified_inventory.alternate[player_name] - 1
+		if alternate < 1 then
+			alternate = alternates
+		end
+	end
 	unified_inventory.alternate[player_name] = alternate
 	unified_inventory.set_inventory_formspec(player,
 			unified_inventory.current_page[player_name])

locale/de.txt

@@ -51,6 +51,10 @@ Copy to craft grid: = Ins Fertigungsraster kopieren:
 All = Alles
 Alternate = Alternative
 Crafting Grid = Fertigungsraster
+Show next recipe = Nächstes Rezept zeigen
+Show next usage = Nächste Verwendung zeigen
+Show previous recipe = Vorheriges Rezept zeigen
+Show previous usage = Vorherige Verwendung zeigen
 Recipe %d of %d = Rezept %d von %d
 Usage %d of %d = Verwendung %d von %d
 No recipes = Keine Rezepte

locale/template.txt

@@ -53,6 +53,10 @@ Copy to craft grid: =
 All = 
 Alternate = 
 Crafting Grid =  
+Show next recipe = 
+Show next usage = 
+Show previous recipe = 
+Show previous usage = 
 Recipe %d of %d = 
 Usage %d of %d = 
 No recipes =

register.lua

@@ -207,6 +207,14 @@ local role_text = {
 	recipe = "Result",
 	usage = "Ingredient",
 }
+local next_alt_text = {
+	recipe = "Show next recipe",
+	usage = "Show next usage",
+}
+local prev_alt_text = {
+	recipe = "Show previous recipe",
+	usage = "Show previous usage",
+}
 local other_dir = {
 	recipe = "usage",
 	usage = "recipe",
@@ -313,7 +321,10 @@ unified_inventory.register_page("craftguide", {
 		if alternates and alternates > 1 then
 			formspec = formspec.."label[5.5,"..(formspecy + 1.6)..";"
 					..string.format(F(recipe_text[dir]), alternate, alternates).."]"
-					.."button[5.5,"..(formspecy + 2)..";2,1;alternate;" .. F("Alternate") .. "]"
+					.."image_button[5.5,"..(formspecy + 2)..";1,1;ui_left_icon.png;alternate_prev;]"
+					.."image_button[6.5,"..(formspecy + 2)..";1,1;ui_right_icon.png;alternate;]"
+					.."tooltip[alternate_prev;"..F(prev_alt_text[dir]).."]"
+					.."tooltip[alternate;"..F(next_alt_text[dir]).."]"
 		end
 		return {formspec = formspec}
 	end,