Reference

UOWP Wallpaper Format

UOWP is the uniOS runtime wallpaper package format. It stores one or more wallpaper variants in a single file.

Identity

  • Extension: .uowp
  • Magic: 0x50574F55 (UOWP, little-endian)
  • Byte order: little-endian
  • Current runtime use: desktop wallpaper loading
  • Default package: light and dark variants built at meson time 
#define UOWP_MAGIC 0x50574F55u // "UOWP", 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;
} UowpHeader;

Directory Entry

typedef struct {
    uint32_t width;
    uint32_t height;
    uint16_t codec;
    uint16_t variant;
    uint16_t color_space;
    uint16_t transfer;
    uint32_t data_offset;
    uint32_t data_size;
    uint32_t preview_offset;
    uint32_t preview_size;
    uint32_t checksum;
} UowpEntry;
  • codec: RAW = 4.
  • variant: default 0, light 1, dark 2, lock blur 3, dynamic 4.
  • color_space: sRGB = 1; transfer: SDR = 1.
  • Entries may carry an embedded preview image.

Runtime Use

The GUI loader (gui_load_uowp) selects an entry by preferred theme variant and target size, then gui_blit_scaled_cover scales and crops it to cover the desktop. The window manager resolves the active path from /data/WALLPAPR.CFG (fallback /etc/wallpaper.conf), the registry request, or the default:

/usr/share/wallpapers/default.uowp

See Runtime configuration and Window manager.

Generation

The default package is generated from assets/wallpapers/wp_light.svg and wp_dark.svg (gitignored inputs):

python3 tools/wallpaper_package.py \
    --light assets/wallpapers/wp_light.svg \
    --dark assets/wallpapers/wp_dark.svg \
    --output default.uowp

Unlike icons and cursors, the default .uowp is built at meson time and is not committed.