Extract Artist Signature from Procreate Canvas

Locates and extracts the artist's digital signature embedded within a Procreate canvas, then uploads it to CDN for display on artwork pages and authenticity certificates.

Usage

extract_signature(artist, artwork, fp = NULL)

Arguments

artist: Character. Artist UUID identifying the creator. Used to construct CDN paths for both input canvas and output signature.
artwork: Character. Artwork UUID for this piece. Determines the CDN path where the extracted signature will be stored.
fp: Character. Optional local file path to the .procreate canvas. If NULL (default), retrieves the canvas from CDN.

Value

Invisible logical. TRUE if signature was newly extracted and uploaded, FALSE if signature already exists in CDN (skipped upload).

Details

Procreate allows artists to embed a signature PNG within the canvas file. This signature provides visual authenticity verification and is displayed on generated artwork certificates and gallery pages.

The signature is stored at `processed/<artist>/<artwork>/signature.png` in the art-data CDN bucket. If a signature already exists at this path, the function returns FALSE without overwriting.

Functions

extract_signature(): Extract signature PNG and upload to CDN

Error Handling

Throws an error if no Signature.png file is found within the canvas archive. Not all canvases contain signatures - older or unsigned works will fail.