# File lib/rubygame/gfx.rb, line 459
  def self.rotozoom_size( size, angle, zoom )
    w, h = size

    case zoom
    when Array
      zx, zy = zoom.collect { |n| n.to_f }
      SDL::Gfx.rotozoomSurfaceSizeXY(w, h, angle, zx, zy)
    when Numeric
      zoom = zoom.to_f
      SDL::Gfx.rotozoomSurfaceSize(w, h, angle, zoom)
    else
      raise ArgumentError, "Invalid zoom factor: #{zoom.inspect}"
    end
  end