Reference

UOIC Icon Format

UOIC is the uniOS runtime icon package format. It stores pre-rendered icon images so userspace does not need to render SVG files at runtime.

Identity

  • Extension: .uoic
  • Magic: 0x43494F55 (UOIC, little-endian)
  • Byte order: little-endian
  • Runtime pixel format: BGRA8888
  • Origin: top-left
  • Alpha: straight or premultiplied, per entry metadata 
#define UOIC_MAGIC 0x43494F55u // "UOIC", little-endian

typedef struct {
    uint32_t magic;
    uint16_t version;
    uint16_t flags;
    uint32_t entry_count;
    uint32_t directory_offset;
    uint32_t directory_size;
    uint32_t metadata_offset;
    uint32_t metadata_size;
} UoicHeader;

Directory Entry

typedef struct {
    uint16_t width;
    uint16_t height;
    uint16_t scale;
    uint16_t variant;
    uint16_t codec;
    uint16_t alpha;
    uint32_t data_offset;
    uint32_t data_size;
    uint32_t decoded_size;
    uint32_t checksum;
} UoicEntry;
  • codec: QOI = 1, BGRA = 3.
  • alpha: straight = 1, premultiplied = 2.
  • Entries carry a decoded-size and checksum for validation.

Runtime Use

The GUI image loader (gui_load_uoic) selects the smallest entry that covers the requested physical size (logical size x display scale), falling back to the largest entry. Decoding supports QOI and raw BGRA.

Generated app icons are staged under:

/usr/share/appicons/

Generation

Source SVG files live under appicons/. The icon generation tool renders fixed sizes and writes .uoic packages:

python3 tools/appicon_rasterize.py \
    --source-root appicons \
    --output-root rootfs/usr/share/appicons

Generated binaries are committed; keep binaries and sources in sync in the same change.