Lists all GIF tag identifiers.

Values:

IGMDTAG_ID_GIF_FORMAT	GIF metadata format identifier.
IGMDTAG_ID_GIF_HEADER	GIF header.
IGMDTAG_ID_GIF_HDR_SIGNATURE	Identifies the GIF Data Stream.
IGMDTAG_ID_GIF_HDR_VERSION	Version number.
IGMDTAG_ID_GIF_SCREEN_DESCRIPTOR	Logical screen descriptor.
IGMDTAG_ID_GIF_SCR_SCREEN_WIDTH	Logical screen width.
IGMDTAG_ID_GIF_SCR_SCREEN_HEIGHT	Logical screen height.
IGMDTAG_ID_GIF_SCR_BACKGROUND_COLOR	Background color index.
IGMDTAG_ID_GIF_SCR_ASPECT_RATIO	Pixel aspect ratio.
IGMDTAG_ID_GIF_SCR_FIELDS	Logical screen packed fields.
IGMDTAG_ID_GIF_SCR_FLD_GL_COLOR_TABLE	Global color table flag.
IGMDTAG_ID_GIF_SCR_FLD_COLOR_RES	Color resolution.
IGMDTAG_ID_GIF_SCR_FLD_SORT	Sort flag.
IGMDTAG_ID_GIF_SCR_FLD_SIZE	Global color table size.
IGMDTAG_ID_GIF_GLOBAL_COLOR_TABLE	Global color table.
IGMDTAG_ID_GIF_IMAGE_DESCRIPTOR	Image descriptor.
IGMDTAG_ID_GIF_IMG_LEFT_POSITION	Image left position.
IGMDTAG_ID_GIF_IMG_TOP_POSITION	Image top position.
IGMDTAG_ID_GIF_IMG_IMAGE_WIDTH	Image width.
IGMDTAG_ID_GIF_IMG_IMAGE_HEIGHT	Image height.
IGMDTAG_ID_GIF_IMG_FIELDS	Image descriptor packed field.
IGMDTAG_ID_GIF_IMG_FLD_LOC_COLOR_TABLE	Local color table flag.
IGMDTAG_ID_GIF_IMG_FLD_INTERLACE	Interlace flag.
IGMDTAG_ID_GIF_IMG_FLD_SORT	Sort flag.
IGMDTAG_ID_GIF_IMG_FLD_SIZE	Local color table size.
IGMDTAG_ID_GIF_LOCAL_COLOR_TABLE	Local color table.
IGMDTAG_ID_GIF_GRAPHIC_CONTROL_EXT	Graphic control extension.
IGMDTAG_ID_GIF_GCE_FIELDS	Graphic control extension packed fields.
IGMDTAG_ID_GIF_GCE_FLD_DISPOSAL_METHOD	Disposal method.
IGMDTAG_ID_GIF_GCE_FLD_USER_INPUT	User input flag.
IGMDTAG_ID_GIF_GCE_FLD_TRANSPARENT	Transparent color flag.
IGMDTAG_ID_GIF_GCE_DELAY_TIME	Delay time.
IGMDTAG_ID_GIF_GCE_TRANSPARENT_COLOR	Transparent color index.
IGMDTAG_ID_GIF_COMMENT_EXTENSION	Comment extension.
IGMDTAG_ID_GIF_PLAIN_TEXT_EXTENSION	Plain text extension.
IGMDTAG_ID_GIF_TXT_GRID_LEFT	Text grid left position.
IGMDTAG_ID_GIF_TXT_GRID_TOP	Text grid top position.
IGMDTAG_ID_GIF_TXT_GRID_WIDTH	Text grid width.
IGMDTAG_ID_GIF_TXT_GRID_HEIGHT	Text grid height.
IGMDTAG_ID_GIF_TXT_CELL_WIDTH	Character cell width.
IGMDTAG_ID_GIF_TXT_CELL_HEIGHT	Character cell height.
IGMDTAG_ID_GIF_TXT_FOREGROUND_COLOR	Text foreground color index.
IGMDTAG_ID_GIF_TXT_BACKGROUND_COLOR	Text background color index.
IGMDTAG_ID_GIF_TXT_TEXT_DATA	Plain text data.
IGMDTAG_ID_GIF_APP_EXTENSION	Application extension.
IGMDTAG_ID_GIF_APP_IDENTIFIER	Application identifier.
IGMDTAG_ID_GIF_APP_AUTH_CODE	Application authentication code.
IGMDTAG_ID_GIF_APP_DATA	Application data.
IGMDTAG_ID_GIF_AFTER_IMAGE_EXT	After image extensions.