Directional input helper methods added.

1 files changed, 77 insertions, 0 deletions

diff --git a/dragon/directional_input_helper_methods.rb b/dragon/directional_input_helper_methods.rb
new file mode 100644
index 0000000..b64839b
--- /dev/null
+++ b/dragon/directional_input_helper_methods.rb
@@ -0,0 +1,77 @@
+# coding: utf-8
+# Copyright 2019 DragonRuby LLC
+# MIT License
+# directional_input_helper_methods.rb has been released under MIT (*only this file*).
+
+module GTK
+  # normalization of behavior related to up|down|left|right on keyboards and controllers
+  module DirectionalInputHelperMethods
+    def self.included klass
+      key_state_methods = [:key_held, :key_down]
+      directional_methods = [:up, :down, :left, :right]
+      method_results = (directional_methods + key_state_methods).map {|m| [m, klass.instance_methods.include?(m)] }
+
+      error_message = <<-S
+* ERROR
+The GTK::DirectionalKeys module should only be included in objects that respond to the following api heirarchy:
+
+- (#{ directional_methods.join("|") })
+- key_held.(#{ directional_methods.join("|") })
+- key_down.(#{ directional_methods.join("|") })
+
+#{klass} does not respond to all of these methods (here is the diagnostics):
+#{method_results.map {|m, r| "- #{m}: #{r}"}.join("\n")}
+
+Please implement the methods that returned false inthe list above.
+S
+      unless method_results.map {|m, result| result}.all?
+        raise error_message
+      end
+    end
+
+    def left_right
+      return -1 if self.left
+      return  1 if self.right
+      return  0
+    end
+
+    def up_down
+      return  1 if self.up
+      return -1 if self.down
+      return  0
+    end
+
+    def directional_vector
+      lr, ud = [self.left_right, self.up_down]
+
+      if lr == 0 && ud == 0
+        return nil
+      elsif lr.abs == ud.abs
+        return [lr.half, ud.half]
+      else
+        return [lr, ud]
+      end
+    end
+
+    def method_missing m, *args
+      # combine the key with ctrl_
+      if m.to_s.start_with?("ctrl_")
+        other_key = m.to_s.split("_").last
+        define_singleton_method(m) do
+          return self.key_up.send(other_key.to_sym) && self.key_up.control
+        end
+
+        return send(m)
+      # see if the key is either held or down
+      elsif self.key_down.respond_to? m
+        define_singleton_method(m) do
+          self.key_down.send(m) || self.key_held.send(m)
+        end
+
+        return send(m)
+      end
+
+      super
+    end
+  end
+end