class GObject::GValue

def set value
  # GLib::logger.debug("GObject::GValue.set") {
  #     "value = #{value.inspect[0..50]}"
  # }
  gtype = self[:gtype]
  fundamental = ::GObject.g_type_fundamental gtype
  case gtype
  when GBOOL_TYPE
    ::GObject.g_value_set_boolean self, (value ? 1 : 0)
  when GINT_TYPE
    ::GObject.g_value_set_int self, value
  when GUINT64_TYPE
    ::GObject.g_value_set_uint64 self, value
  when GDOUBLE_TYPE
    ::GObject.g_value_set_double self, value
  when GSTR_TYPE
    ::GObject.g_value_set_string self, value
  when Vips::REFSTR_TYPE
    ::Vips.vips_value_set_ref_string self, value
  when Vips::ARRAY_INT_TYPE
    value = [value] unless value.is_a? Array
    Vips.vips_value_set_array_int self, nil, value.length
    ptr = Vips.vips_value_get_array_int self, nil
    ptr.write_array_of_int32 value
  when Vips::ARRAY_DOUBLE_TYPE
    value = [value] unless value.is_a? Array
    # this will allocate an array in the gvalue
    Vips.vips_value_set_array_double self, nil, value.length
    # pull the array out and fill it
    ptr = Vips.vips_value_get_array_double self, nil
    ptr.write_array_of_double value
  when Vips::ARRAY_IMAGE_TYPE
    value = [value] unless value.is_a? Array
    Vips.vips_value_set_array_image self, value.length
    ptr = Vips.vips_value_get_array_image self, nil
    ptr.write_array_of_pointer value
    # the gvalue needs a ref on each of the images
    value.each { |image| ::GObject.g_object_ref image }
  when Vips::BLOB_TYPE
    len = value.bytesize
    ptr = GLib.g_malloc len
    Vips.vips_value_set_blob self, GLib::G_FREE, ptr, len
    ptr.write_bytes value
  else
    case fundamental
    when GFLAGS_TYPE
      ::GObject.g_value_set_flags self, value
    when GENUM_TYPE
      enum_value = GValue.from_nick(self[:gtype], value)
      ::GObject.g_value_set_enum self, enum_value
    when GOBJECT_TYPE
      ::GObject.g_value_set_object self, value
    else
      raise Vips::Error, "unimplemented gtype for set: " \
        "#{::GObject.g_type_name gtype} (#{gtype})"
    end
  end
end