Colorspace color primaries, as described by https://www.itu.int/rec/T-REC-H.273-201612-S/en
Defined in <SDL3/SDL_pixels.h>
typedef enum SDL_ColorPrimaries
{0,
SDL_COLOR_PRIMARIES_UNKNOWN = 1, /**< ITU-R BT.709-6 */
SDL_COLOR_PRIMARIES_BT709 = 2,
SDL_COLOR_PRIMARIES_UNSPECIFIED = 4, /**< ITU-R BT.470-6 System M */
SDL_COLOR_PRIMARIES_BT470M = 5, /**< ITU-R BT.470-6 System B, G / ITU-R BT.601-7 625 */
SDL_COLOR_PRIMARIES_BT470BG = 6, /**< ITU-R BT.601-7 525, SMPTE 170M */
SDL_COLOR_PRIMARIES_BT601 = 7, /**< SMPTE 240M, functionally the same as SDL_COLOR_PRIMARIES_BT601 */
SDL_COLOR_PRIMARIES_SMPTE240 = 8, /**< Generic film (color filters using Illuminant C) */
SDL_COLOR_PRIMARIES_GENERIC_FILM = 9, /**< ITU-R BT.2020-2 / ITU-R BT.2100-0 */
SDL_COLOR_PRIMARIES_BT2020 = 10, /**< SMPTE ST 428-1 */
SDL_COLOR_PRIMARIES_XYZ = 11, /**< SMPTE RP 431-2 */
SDL_COLOR_PRIMARIES_SMPTE431 = 12, /**< SMPTE EG 432-1 / DCI P3 */
SDL_COLOR_PRIMARIES_SMPTE432 = 22, /**< EBU Tech. 3213-E */
SDL_COLOR_PRIMARIES_EBU3213 = 31
SDL_COLOR_PRIMARIES_CUSTOM = } SDL_ColorPrimaries;
This enum is available since SDL 3.1.3.