# element.rb: base class of all drawable elements
# copyright (c) 2006, 2007, 2008, 2009 by Vincent Fourmond: 
  
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
  
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details (in the COPYING file).


require 'ctioga2/utils'
require 'ctioga2/log'

# This module contains all the classes used by ctioga
module CTioga2

  # This module contains all graphical elements of CTioga2
  module Graphics

    # All elements that can be drawn onto a FigureMaker object
    module Elements
      
      # The base class for every single object that is drawn on
      # Tioga's output.
      class TiogaElement
        include Log

        # The parent Container.
        attr_accessor :parent

        # Details pertaining to the location of the object, as a
        # LocationStyle object
        attr_writer :location

        # Whether the object is clipped by default or not.
        attr_accessor :clipped

        
        # Depth
        attr_writer :depth

        def initialize()
          @clipped = true

          @depth = 50           # Hey, like xfig
          
          @gp_cache = {}
        end

        def depth
          @depth || 50
        end

        # Makes sure there is a location when one asks for it.
        def location
          @location ||= Styles::LocationStyle.new
          return @location
        end

        # This function must be called with a FigureMaker object to
        # draw the contents of the TiogaElement onto it. It calls
        # #real_do, which should be redefined by the children. You can
        # redefine _do_ too if you need another debugging output.
        def do(f)
          debug { "plotting #{self.inspect}" }
          @gp_cache = {}
          real_do(f)
        end

        # We plot everything but parent. If a prefix is given, it is prepended
        # to all lines but the first (for indentation)
        def inspect(prefix="")
          ret = "#<#{self.class.name}:\n"
          for i in instance_variables
            next if i == "@parent"
            var = instance_variable_get(i)
            ret += "#{prefix}  - #{i} -> "
            if var.is_a? TiogaElement
              ret += "#{var.inspect("#{prefix}  ")}\n"
            else
              ret += "#{var.inspect}\n"
            end
          end
          ret += "#{prefix}>"
          return ret
        end

        protected
        
        def real_do(t)
          raise "Should be reimplemented by children"
        end
      end 


      # The base class for all dataset-based elements
      class PlotBasedElement < TiogaElement

        # The Data::Dataset object that should get plotted.
        attr_accessor :dataset

        # A Styles::CurveStyle object saying how the curve should be
        # drawn.
        attr_accessor :curve_style

        undef :location=, :location

        # Returns the LocationStyle object of the curve. Returns the
        # one from #curve_style.
        def location
          return @curve_style.location
        end

        undef :clipped, :clipped=

        def clipped
          return @curve_style.clipped
        end

        undef :depth, :depth=

        def depth
          return @curve_style.depth
        end

        def initialize()
          super()
        end
      end

    end
  end
end