Identifies transparency modes.

Values:

IG_DSPL_TRANSPARENCY_NONE	Transparency is disabled.
IG_DSPL_TRANSPARENCY_COLOR	Transparency color is enabled. Pixels which color is equal to the Transparency Color value are displayed transparent when drawing the image.
IG_DSPL_TRANSPARENCY_MASK	Transparency Mask is enabled and the Transparency Mask image is used to specify transparent pixels.
IG_DSPL_TRANSPMASK_STRETCH_TO_IMAGE	If this flag is set, the transparency Mask image is resized and oriented along with the image being displayed. This flag is only used when the transparency mask is enabled.
IG_DSPL_TRANSPMASK_LOCATE_TO_IMAGE	If this flag is set, the transparency mask location is calculated relatively to the Image Rectangle. The mask is oriented along with the image. This flag is only used when the transparency mask is enabled.
IG_DSPL_TRANSPMASK_LOCATE_TO_CLIPRECT	If this flag is set, the transparency mask location is calculated relatively to the Clipping Rectangle. This flag is only used when the transparency mask is enabled.
IG_DSPL_TRANSPMASK_LOCATE_ABSOLUTE	If this flag is set, the transparency mask left-top corner is located according to the MaskLocation option. This flag is only used when the transparency mask is enabled.
IG_DSPL_TRANSPMASK_LOCATE_MODE	Bit mask for mask location modes.