Stirling-PDF/app/common
Balázs Szücs ec1ac4cb2d
feat(cbr-to-pdf,pdf-to-cbr): add PDF to/from CBR conversion with ebook optimization option (#4581)
# Description of Changes

This pull request adds support for converting CBR (Comic Book RAR) files
to PDF, optimizes CBZ/CBR-to-PDF conversion for e-readers using
Ghostscript, and improves file type detection and image file handling.
It introduces the `CbrUtils` and `PdfToCbrUtils` utility classes,
refactors CBZ conversion logic, and integrates these features into the
API controller. The most important changes are grouped below.

### CBR Support and Conversion:

- Added the `com.github.junrar:junrar` dependency to support RAR/CBR
archive extraction in `build.gradle`. (https://github.com/junrar/junrar
and https://github.com/junrar/junrar?tab=License-1-ov-file#readme for
repo and license)
- Introduced the new utility class `CbrUtils` for converting CBR files
to PDF, including image extraction, sorting, and error handling.
- Added the `PdfToCbrUtils` utility class to convert PDF files into CBR
archives by rendering each page as an image and packaging them.

### CBZ/CBR Conversion Optimization:

- Refactored `CbzUtils.convertCbzToPdf` to support optional Ghostscript
optimization for e-reader compatibility and added a new method for this.
- Added `GeneralUtils.optimizePdfWithGhostscript`, which uses
Ghostscript to optimize PDFs for e-readers, and integrated error
handling.

### API Controller Integration:

- Updated `ConvertImgPDFController` to support CBR conversion, CBZ/CBR
optimization toggling, and Ghostscript availability checks.

### Endpoints
<img width="1298" height="522" alt="image"
src="https://github.com/user-attachments/assets/144d3e03-a637-451a-9c35-f784b2a66dc1"
/>

<img width="1279" height="472" alt="image"
src="https://github.com/user-attachments/assets/879f221d-b775-4224-8edb-a23dbea6a0ca"
/>

### UI

<img width="384" height="105" alt="image"
src="https://github.com/user-attachments/assets/5f861943-0706-4fad-8775-c40a9c1f3170"
/>


### File Type and Image Detection Improvements:

- Improved file extension detection for comic book files and image files
in `CbzUtils` and added a shared regex pattern utility for image files.

### Additional notes:
- Please keep in mind new the dependency, this is not dependency-free
implementation (as opposed to CBZ converter)
- RAR 5 currently not supported. (because JUNRAR does not support it)
- Added the new ebook optimization func to GeneralUtils since we'll soon
(hopefully) at least 3 book/ebook formats (EPUB, CBZ, CBR) all of which
can use it.
- Once again this has been thoroughly tested but can't share actual
"real life" file due to copyright.


Closes: #775
<!--
Please provide a summary of the changes, including:

- What was changed
- Why the change was made
- Any challenges encountered

Closes #(issue_number)
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---

## Checklist

### General

- [x] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [x] 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)
- [x] I have performed a self-review of my own code
- [x] My changes generate no new warnings

### Documentation

- [x] 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)

### UI Changes (if applicable)

- [x] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [x] 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 <bszucs1209@gmail.com>
2025-10-04 11:15:23 +01:00
..
src feat(cbr-to-pdf,pdf-to-cbr): add PDF to/from CBR conversion with ebook optimization option (#4581) 2025-10-04 11:15:23 +01:00
.gitignore refactor: move modules under app/ directory and update file paths (#3938) 2025-07-14 20:53:11 +01:00
build.gradle feat(cbr-to-pdf,pdf-to-cbr): add PDF to/from CBR conversion with ebook optimization option (#4581) 2025-10-04 11:15:23 +01:00