Colorspace transfer characteristics.
Defined in <SDL3/SDL_pixels.h>
typedef enum SDL_TransferCharacteristics
{0,
SDL_TRANSFER_CHARACTERISTICS_UNKNOWN = 1, /**< Rec. ITU-R BT.709-6 / ITU-R BT1361 */
SDL_TRANSFER_CHARACTERISTICS_BT709 = 2,
SDL_TRANSFER_CHARACTERISTICS_UNSPECIFIED = 4, /**< ITU-R BT.470-6 System M / ITU-R BT1700 625 PAL & SECAM */
SDL_TRANSFER_CHARACTERISTICS_GAMMA22 = 5, /**< ITU-R BT.470-6 System B, G */
SDL_TRANSFER_CHARACTERISTICS_GAMMA28 = 6, /**< SMPTE ST 170M / ITU-R BT.601-7 525 or 625 */
SDL_TRANSFER_CHARACTERISTICS_BT601 = 7, /**< SMPTE ST 240M */
SDL_TRANSFER_CHARACTERISTICS_SMPTE240 = 8,
SDL_TRANSFER_CHARACTERISTICS_LINEAR = 9,
SDL_TRANSFER_CHARACTERISTICS_LOG100 = 10,
SDL_TRANSFER_CHARACTERISTICS_LOG100_SQRT10 = 11, /**< IEC 61966-2-4 */
SDL_TRANSFER_CHARACTERISTICS_IEC61966 = 12, /**< ITU-R BT1361 Extended Colour Gamut */
SDL_TRANSFER_CHARACTERISTICS_BT1361 = 13, /**< IEC 61966-2-1 (sRGB or sYCC) */
SDL_TRANSFER_CHARACTERISTICS_SRGB = 14, /**< ITU-R BT2020 for 10-bit system */
SDL_TRANSFER_CHARACTERISTICS_BT2020_10BIT = 15, /**< ITU-R BT2020 for 12-bit system */
SDL_TRANSFER_CHARACTERISTICS_BT2020_12BIT = 16, /**< SMPTE ST 2084 for 10-, 12-, 14- and 16-bit systems */
SDL_TRANSFER_CHARACTERISTICS_PQ = 17, /**< SMPTE ST 428-1 */
SDL_TRANSFER_CHARACTERISTICS_SMPTE428 = 18, /**< ARIB STD-B67, known as "hybrid log-gamma" (HLG) */
SDL_TRANSFER_CHARACTERISTICS_HLG = 31
SDL_TRANSFER_CHARACTERISTICS_CUSTOM = } SDL_TransferCharacteristics;
These are as described by https://www.itu.int/rec/T-REC-H.273-201612-S/en
This enum is available since SDL 3.1.3.