new framework

lib/bbs/container.rb

@@ -0,0 +1,66 @@
+# frozen_string_literal: true
+
+module BBS
+  # A Widget that holds children.
+  class Container < Widget
+    attr_reader :children
+
+    def initialize(**kw)
+      super
+      @children = []
+    end
+
+    def add(child)
+      child.parent = self
+      @children << child
+      child
+    end
+
+    def remove(child)
+      child.parent = nil if @children.delete(child)
+    end
+
+    def clear
+      @children.each { |c| c.parent = nil }
+      @children.clear
+    end
+
+    def focusable_descendants
+      result = []
+      walk { |w| result << w if w.focusable? && w.visible }
+      result
+    end
+
+    def walk(&block)
+      yield self
+      @children.each do |c|
+        c.is_a?(Container) ? c.walk(&block) : (yield c)
+      end
+    end
+
+    def find(id)
+      walk { |w| return w if w.id == id }
+      nil
+    end
+
+    def render(frame)
+      @children.each { |c| c.render(frame) if c.visible }
+    end
+
+    def hit_test(x, y)
+      return nil unless bounds.contains?(x, y) && visible
+      # iterate top-most last so we test in reverse
+      @children.reverse.each do |child|
+        next unless child.visible
+        hit = child.hit_test(x, y)
+        return hit if hit
+      end
+      self
+    end
+
+    def theme=(value)
+      super
+      @children.each { |c| c.theme = value }
+    end
+  end
+end