class GObject::GValue
Represent a GValue
. Example use:
“‘ruby gvalue = GValue::alloc
gvalue.init GObject::GDOUBLE_TYPE gvalue.set 3.1415 value = gvalue.get # optional – drop any ref the gvalue had gvalue.unset “`
Lifetime is managed automatically. It doesn’t know about all GType values, but it does know the ones that libvips uses.
Public Class Methods
Source
# File lib/vips/gvalue.rb, line 63 def self.alloc # allocate memory memory = FFI::MemoryPointer.new GValue # make this alloc autorelease ... we mustn't release in # GValue::release, since we are used to wrap GValue pointers # made by other people pointer = FFI::Pointer.new GValue, memory # ... and wrap in a GValue return GValue.new pointer end
Allocate memory for a GValue
and return a class wrapper. Memory will be freed automatically when it goes out of scope. The GValue
is inited to 0, use {GValue.init} to set a type.
@return [GValue] a new gvalue set to 0
Source
# File lib/vips/gvalue.rb, line 28 def self.from_nick(gtype, value) value = value.to_s if value.is_a? Symbol if value.is_a? String # libvips expects "-" as a separator in enum names, but "_" is more # convenient for ruby, eg. :b_w value = Vips::vips_enum_from_nick "ruby-vips", gtype, value.tr("_", "-") if value == -1 raise Vips::Error end end value end
convert an enum value (str/symb/int) into an int ready for libvips
Source
# File lib/vips/gvalue.rb, line 53 def self.release ptr # GLib::logger.debug("GObject::GValue::release") {"ptr = #{ptr}"} ::GObject::g_value_unset ptr end
Source
# File lib/vips/gvalue.rb, line 44 def self.to_nick(gtype, enum_value) enum_name = Vips::vips_enum_nick gtype, enum_value if enum_name == nil raise Vips::Error end enum_name.to_sym end
convert an int enum back into a symbol
Public Instance Methods
Source
# File lib/vips/gvalue.rb, line 171 def get gtype = self[:gtype] fundamental = ::GObject::g_type_fundamental gtype result = nil case gtype when GBOOL_TYPE result = ::GObject::g_value_get_boolean(self) != 0 ? true : false when GINT_TYPE result = ::GObject::g_value_get_int self when GUINT64_TYPE result = ::GObject::g_value_get_uint64 self when GDOUBLE_TYPE result = ::GObject::g_value_get_double self when GSTR_TYPE result = ::GObject::g_value_get_string self when Vips::REFSTR_TYPE len = Vips::SizeStruct.new result = ::Vips::vips_value_get_ref_string self, len when Vips::ARRAY_INT_TYPE len = Vips::IntStruct.new array = Vips::vips_value_get_array_int self, len result = array.get_array_of_int32 0, len[:value] when Vips::ARRAY_DOUBLE_TYPE len = Vips::IntStruct.new array = Vips::vips_value_get_array_double self, len result = array.get_array_of_double 0, len[:value] when Vips::ARRAY_IMAGE_TYPE len = Vips::IntStruct.new array = Vips::vips_value_get_array_image self, len result = array.get_array_of_pointer 0, len[:value] result.map! do |pointer| ::GObject::g_object_ref pointer Vips::Image.new pointer end when Vips::BLOB_TYPE len = Vips::SizeStruct.new array = Vips::vips_value_get_blob self, len result = array.get_bytes 0, len[:value] else case fundamental when GFLAGS_TYPE result = ::GObject::g_value_get_flags self when GENUM_TYPE enum_value = ::GObject::g_value_get_enum(self) result = GValue.to_nick self[:gtype], enum_value when GOBJECT_TYPE obj = ::GObject::g_value_get_object self # g_value_get_object() does not add a ref ... we need to add # one to match the unref in gobject release ::GObject::g_object_ref obj result = Vips::Image.new obj else raise Vips::Error, "unimplemented gtype for get: " + "#{::GObject::g_type_name gtype} (#{gtype})" end end # GLib::logger.debug("GObject::GValue.get") { # "result = #{result.inspect[0..50]}" # } return result end
Get the value of a GValue
. The value is converted to a Ruby type in the obvious way.
@return [Any] the value held by the GValue
Source
# File lib/vips/gvalue.rb, line 79 def init gtype ::GObject::g_value_init self, gtype end
Set the type of thing a gvalue can hold.
@param gtype [GType] the type of thing this GValue
can hold.
Source
# File lib/vips/gvalue.rb, line 87 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
Set the value of a GValue
. The value is converted to the type of the GValue
, if possible.
@param value [Any] The value to set