| /** Image handling constants */ | |
| export const IMAGE = { | |
| /** JPEG quality used when transcoding HEIC images. */ | |
| HEIC_JPEG_QUALITY: 0.85, | |
| /** Unit conversion: pixels per megapixel. */ | |
| MEGAPIXELS_TO_PIXELS: 1_000_000 | |
| } as const; | |
| /** | |
| * JPEG and EXIF binary format constants for orientation parsing. | |
| */ | |
| export const EXIF = { | |
| /** APP1 segment marker byte, carries the EXIF payload */ | |
| APP1_MARKER: 0xe1, | |
| /** "Exif" signature opening the APP1 payload, big endian uint32 */ | |
| EXIF_SIGNATURE: 0x45786966, | |
| /** Size in bytes of one IFD directory entry */ | |
| IFD_ENTRY_SIZE: 12, | |
| /** JPEG start of image marker */ | |
| JPEG_SOI_MARKER: 0xffd8, | |
| /** EXIF tag id holding the orientation value */ | |
| ORIENTATION_TAG: 0x0112, | |
| /** Bytes of file prefix to scan, the APP1 EXIF segment sits near the start */ | |
| SCAN_BYTE_LIMIT: 128 * 1024, | |
| /** Start of scan marker byte, compressed data begins and no EXIF follows */ | |
| SOS_MARKER: 0xda, | |
| /** TIFF byte order mark for little endian ("II") */ | |
| TIFF_LITTLE_ENDIAN: 0x4949, | |
| /** TIFF magic number following the byte order mark */ | |
| TIFF_MAGIC: 42 | |
| } as const; | |