lib/shoes/swt/slot.rb in shoes-swt-4.0.0.pre12 vs lib/shoes/swt/slot.rb in shoes-swt-4.0.0.rc1

@@ -1,6 +1,7 @@
 # frozen_string_literal: true
+
 class Shoes
   module Swt
     class Slot
       include Common::Container
       include Common::Clickable
@@ -12,30 +13,40 @@
         @dsl = dsl
         @parent = parent
         @real = parent.real
 
         @app = @parent.app
+
+        @scroll = ::Swt::Widgets::Slider.new(@app.real, ::Swt::SWT::VERTICAL)
+        @scroll.add_selection_listener do |_event|
+          update_scroll
+        end
       end
 
       # needed by Layouter code, but slots are no physical elements so they
       def update_position
       end
 
-      # This is more like a temporary work around until slots have a real
-      # backend representations that can just hide their contents all together
-      # I decided to put this logic in the backend since the hiding is a backend
-      # responsibility, although this is more DSL code
-      # #904 #905
-      def update_visibility
-        # Only alter contents on a visibility change
-        return if @last_hidden_state == dsl.hidden?
+      def update_scroll
+        @dsl.scroll_top = @scroll.selection
+      end
 
-        @last_hidden_state = dsl.hidden?
+      # This is more than the scrollbar is expected to be on any OS
+      SCROLLBAR_MAX_WIDTH = 20
 
-        if @last_hidden_state
-          dsl.contents.each(&:hide)
-        else
-          dsl.contents.each(&:show)
+      # For some reason, if we set max to match, you can't get past last 10!
+      SCROLLBAR_PADDING = 10
+
+      def update_visibility
+        @scroll.set_visible(@dsl.scroll && @dsl.scroll_max.positive?)
+
+        if @dsl.scroll
+          @scroll.selection = @dsl.scroll_top
+          @scroll.maximum = @dsl.scroll_max + SCROLLBAR_PADDING
+          @scroll.set_bounds @dsl.element_right - SCROLLBAR_MAX_WIDTH + 1,
+                             @dsl.element_top,
+                             SCROLLBAR_MAX_WIDTH,
+                             @dsl.element_height
         end
       end
 
       def redraw_target
         @dsl