# Description of Changes
Improves PDF rendering in the viewer by adding digital signature field
support,
cleaning up overlay rendering, and migrating the contrast tool off
pdf-lib to PDFium WASM.
### Signature Field Overlay
- Added `SignatureFieldOverlay` component that renders digital signature
form fields
- Renders appearance streams when present; shows a fallback badge for
unsigned fields
- Uses PDFium WASM for bitmap extraction
### Overlay Rendering
- Integrated `SignatureFieldOverlay` and `ButtonAppearanceOverlay` into
`LocalEmbedPDF`
- Overlays are now clipped to page boundaries
- Clarified in `EmbedPdfViewer` that frontend overlays use PDFium WASM,
backend overlays use PDFBox
### Contrast Tool Migration
- Replaced pdf-lib with PDFium WASM in `useAdjustContrastOperation`
- PDF page creation and image embedding now go through PDFium APIs
directly
- Updated bitmap handling and memory management accordingly
### Cleanup
- Fixed import ordering in viewer components
- Removed stale comments in the contrast operation hook
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## Checklist
### General
- [ ] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [ ] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md)
(if applicable)
- [ ] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md)
(if applicable)
- [ ] I have performed a self-review of my own code
- [ ] My changes generate no new warnings
### Documentation
- [ ] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [ ] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)
### Translations (if applicable)
- [ ] I ran
[`scripts/counter_translation.py`](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/docs/counter_translation.md)
### UI Changes (if applicable)
- [ ] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)
### Testing (if applicable)
- [ ] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md#6-testing)
for more details.
---------
Signed-off-by: Balázs Szücs <[email protected]>
Co-authored-by: Reece Browne <[email protected]>
