Optional PDF/A validation and PDF/A compliant signature support
Some users seem to use this feature by internal policy, this is not enforced by law.
- Some PDF have PDF/A declaration, but they could be not compliant. Adding an optional validation report will likely fail in a lot of places, so it makes sense to have this feature disabled by default. PDF/A validation dependencies are size expensive and likely will increase the jar size substantially.
- When adding PDF/A checkbox in settings for validation, also consider a PDF/A checkbox for non-transparent signatures and embedded fonts. This checkbox should make the signature background opaque, not allowing transparent colors in settings (PDF/A forbids transparency), it could fall back to white background because the default is transparent. This increases the size because requires embedding all used, and requires subsetting the used fonts for smaller font embedding size. This is even required when one or more standard 14 fonts (Helvetica, Times, Courier, Symbol and Zapf Dingbats) are used.