Luban is an Android image compression library that replicates the compression strategy of WeChat Moments.
The library addresses the challenge of balancing image quality against file size when handling photos from modern high-resolution cameras. Rather than applying uniform compression, it reverses the compression algorithm used by WeChat by analyzing nearly a hundred images of different resolutions sent through WeChat Moments, comparing originals to compressed versions. The tool implements an adaptive unified image compression algorithm that dynamically applies different strategies based on the source image's resolution characteristics. It uses an intelligent resolution decision system that sets 1440 pixels as the default short-edge baseline for modern screens, automatically detects panoramic images and applies different handling, protects against out-of-memory errors on extremely long screenshots, and includes safeguards against ultra-high-pixel images. The compression approach also adapts bitrate control based on image size categories, from minimal compression on very small images to aggressive compression on large files.
Developers should choose this tool if they are building Android applications that handle user-generated photos and need compression that closely matches WeChat's visual quality standards. The library suits projects where users upload images through social features or messaging, and where file size reduction is critical for bandwidth and storage. The tool is a Kotlin rewrite of the original Luban project, incorporating optimizations with Kotlin Coroutines and TurboJPEG for improved performance and compression quality.
The project maintains active development with regular updates to its core algorithm. The codebase shows ongoing refinement of compression heuristics and edge-case handling. Documentation is provided in both Chinese and English, supporting a broad user base. The tool includes comprehensive examples for both Kotlin coroutines and Java Builder pattern usage, indicating attention to different developer preferences and Android development approaches.
