start/stop animations with show/hide and pass show/hide down children

graphics/element.lua

@@ -141,6 +141,14 @@ function element.new(args)
         return nil
     end
 
+    -- start animations
+    function protected.start_anim()
+    end
+
+    -- stop animations
+    function protected.stop_anim()
+    end
+
     -- get public interface
     ---@return graphics_element element, element_id id
     function protected.get() return public, self.id end
@@ -272,10 +280,20 @@ function element.new(args)
     -- show the element
     function public.show()
         protected.window.setVisible(true)
+        protected.start_anim()
+
+        for i = 1, #self.children do
+            self.children[i].show()
+        end
     end
 
     -- hide the element
     function public.hide()
+        protected.stop_anim()
+        for i = 1, #self.children do
+            self.children[i].hide()
+        end
+
         protected.window.setVisible(false)
     end
 

graphics/elements/animations/waiting.lua

@@ -16,6 +16,7 @@ local element = require("graphics.element")
 ---@return graphics_element element, element_id id
 local function waiting(args)
     local state = 0
+    local run_animation = false
 
     args.width = 4
     args.height = 3
@@ -28,7 +29,8 @@ local function waiting(args)
     local blit_fg_2x = e.fg_bg.blit_fgd .. e.fg_bg.blit_fgd
     local blit_bg_2x = e.fg_bg.blit_bkg .. e.fg_bg.blit_bkg
 
-    local function update()
+    -- tick the animation
+    local function animate()
         e.window.clear()
 
         if state >= 0 and state < 7 then
@@ -82,10 +84,23 @@ local function waiting(args)
         state = state + 1
         if state >= 12 then state = 0 end
 
-        tcd.dispatch(0.5, update)
+        if run_animation then
+            tcd.dispatch(0.5, animate)
+        end
     end
 
-    update()
+    -- start the animation
+    function e.start_anim()
+        run_animation = true
+        animate()
+    end
+
+    -- stop the animation
+    function e.stop_anim()
+        run_animation = false
+    end
+
+    e.start_anim()
 
     return e.get()
 end