Icons.bni

Icons.bni is a file downloaded by Blizzard's games during their handshake with Battle.net and is used to display client icons in chat, including icons like tournament trophies and number of wins. There are also product-specific variations of this file such as icons_STAR.bni. The correct file to use can be obtained by sending SID_GETICONDATA after client authentication.

Standard File Format

(UINT32) Size of BNI header (always 16)
(UINT16) BNI Version
(UINT16) Alignment Padding (Unused)
(UINT32) Number of Icons
(UINT32) Image data Offset

For each icon:
    (UINT32)   Flags
    (UINT32)   X Size
    (UINT32)   Y Size
    (UINT32)[] Icon Code (zero-terminated)

(VOID) Targa image data

• The BNI version value has only been observed to be 0x01. This document only applies to that version. The BNI format was replaced by a separate system using MPQ files, as can be seen in icons-WAR3.bni (which is actually an MPQ file with a different extension).
• The image data offset is the position in the file where the Targa image data begins.
• The flags value, when non-zero, corresponds to a user chat flag that the icon should be displayed for. In the case of multiple matching flags with icons, the first should be used.
• X Size and Y Size refer to the width and height of the image in pixels, respectively.
• Icon code is an array of DWORD-strings corresponding to the icon code value from a chat user statstring. This is only used when the flags for an icon is set to 0x00, otherwise it is a single DWORD with a value of 0. The array will always end on a DWORD value of 0 and appears to have a maximum limit of 32 values.
• Targa image data is typically in 24-bit TrueColor (RGB) compressed with run-length encoding.

Additional Notes

• This document, written by Kane, has a good overview of the relevant parts of the format, including the Targa data.
• More information on the Targa format can be found here.
• Some unusual BNI files have been found in circulation. These have been found with some of the following format-breaking differences:
  • icons_clan.bni and icons_lag.bni have a header size value that is actually the image data offset, minus 4. Their image data offset value is 0xFFFFFFFF. Their pixel-origin in the Targa data is also 0x30 (top-right) which seems to be obscure and not supported by some image manipulation programs/libraries.
  • classic_icons.bni has a NULL (0) icon code for its first 45 icons, followed by the NULL (0) code array terminator, which can break for code expecting the list to end on the first NULL value.
• Observed samples of this file (including the unusual ones) can be found here.
• Some BNI files may contain multiple icons with flags 0 and no icon codes. These were reported to be referenced directly by-index from the game clients.