From af24fc86908838278c74d959f95ba89e9e942f51 Mon Sep 17 00:00:00 2001
From: Cyberarm <matthewlikesrobots@gmail.com>
Date: Sun, 31 Jan 2021 09:44:46 -0600
Subject: [PATCH] Added vertical scrolling support for containers (no scrollbar
 yet)

---
 lib/cyberarm_engine/ui/element.rb            | 16 ++++++++
 lib/cyberarm_engine/ui/elements/container.rb | 39 ++++++++++++++------
 2 files changed, 44 insertions(+), 11 deletions(-)

diff --git a/lib/cyberarm_engine/ui/element.rb b/lib/cyberarm_engine/ui/element.rb
index 6395048..4ad7421 100644
--- a/lib/cyberarm_engine/ui/element.rb
+++ b/lib/cyberarm_engine/ui/element.rb
@@ -226,6 +226,22 @@ module CyberarmEngine
       (@style.border_thickness_top + @style.padding_top) + (@style.padding_bottom + @style.border_thickness_bottom)
     end
 
+    def scroll_width
+      @children.sum { |c| c.width } + noncontent_width
+    end
+
+    def scroll_height
+      @children.sum { |c| c.height } + noncontent_height
+    end
+
+    def max_scroll_width
+      scroll_width - width
+    end
+
+    def max_scroll_height
+      scroll_height - height
+    end
+
     def dimensional_size(size, dimension)
       raise "dimension must be either :width or :height" unless %i[width height].include?(dimension)
 
diff --git a/lib/cyberarm_engine/ui/elements/container.rb b/lib/cyberarm_engine/ui/elements/container.rb
index 4c29d1f..67903af 100644
--- a/lib/cyberarm_engine/ui/elements/container.rb
+++ b/lib/cyberarm_engine/ui/elements/container.rb
@@ -4,14 +4,13 @@ module CyberarmEngine
       include Common
 
       attr_accessor :stroke_color, :fill_color
-      attr_reader :children, :gui_state, :scroll_x, :scroll_y
+      attr_reader :children, :gui_state, :scroll_position
 
       def initialize(options = {}, block = nil)
         @gui_state = options.delete(:gui_state)
         super
 
-        @scroll_x = 0
-        @scroll_y = 0
+        @scroll_position = Vector.new(0, 0)
         @scroll_speed = 10
 
         @text_color = options[:color]
@@ -98,6 +97,8 @@ module CyberarmEngine
 
       def recalculate
         @current_position = Vector.new(@style.margin_left + @style.padding_left, @style.margin_top + @style.padding_top)
+        @current_position += @scroll_position
+
         return unless visible?
 
         Stats.increment(:gui_recalculations_last_frame, 1)
@@ -189,15 +190,31 @@ module CyberarmEngine
         @current_position.y += element.outer_height
       end
 
-      # def mouse_wheel_up(sender, x, y)
-      #   @children.each {|c| c.y -= @scroll_speed}
-      #   @children.each {|c| c.recalculate}
-      # end
+      def mouse_wheel_up(sender, x, y)
+        return unless @style.scroll
+        return if height < max_scroll_height
 
-      # def mouse_wheel_down(sender, x, y)
-      #   @children.each {|c| c.y += @scroll_speed}
-      #   @children.each {|c| c.recalculate}
-      # end
+        if @scroll_position.y < 0
+          @scroll_position.y += @scroll_speed
+          @scroll_position.y = 0 if @scroll_position.y > 0
+          recalculate
+
+          return :handled
+        end
+      end
+
+      def mouse_wheel_down(sender, x, y)
+        return unless @style.scroll
+        return if height < max_scroll_height
+
+        if @scroll_position.y.abs < max_scroll_height
+          @scroll_position.y -= @scroll_speed
+          @scroll_position.y = -max_scroll_height if @scroll_position.y.abs > max_scroll_height
+          recalculate
+
+          return :handled
+        end
+      end
 
       def value
         @children.map { |c| c.class }.join(", ")