Difegue
Port Python HD thumbnail generator to Java for server integration
This PR ports the functionality from tools/mio_hd_thumbnail.py to Java, enabling the main server to generate high-quality game thumbnails without external Python dependencies.
Problem
The existing Python script mio_hd_thumbnail.py generates high-quality 192×128px previews of .mio game files, but requires external execution and cannot be integrated with the main Java server. This creates a dependency on Python and PIL, making deployment more complex.
Solution
Complete Java port with server integration:
New Components
-
BitField.java: Utility class for bit field manipulation (equivalent to Python'sbfclass) -
MioUtils.getHDGamePreview(): Core method that generates 192×128px HD thumbnails from .mio files -
Enhanced DownloadServlet: Added
&hdparameter to request HD previews via HTTP
Key Features Ported
- Validates .mio file format (magic "DSMIO_S" and 65536 byte size)
- Parses background data using the same 16-color palette
- Processes up to 15 sprite objects with proper positioning logic
- Handles object attachments and area-based placement with randomization
- Combines all elements with correct layering
Server Integration
Users can now request HD thumbnails directly from the server:
/download?type=game&id=HASH&preview&hd
The implementation maintains full backward compatibility - standard 95×63px previews remain the default, and HD generation only occurs when explicitly requested.
Testing
Comprehensive test suite validates:
- Error handling for invalid files
- Correct image dimensions (192×128px)
- Fallback behavior when HD generation fails
- Integration with existing preview functionality
The Java implementation produces the same high-quality output as the Python script while integrating seamlessly with the existing server architecture.
💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.
