Melatonin Blur is a batteries-included, cross-platform CPU blur and shadow compositing library for the JUCE C++ framework.
Batteries-included means it aims to give you everything out of the box:
- π©βπ¨ Figma/CSS-accurate drop and inner shadows on paths
- π Drop and Inner Text shadows
- π πΌ Supports both filled and stroked paths
- π ARGB image blurs
- π Fast! (see benchmarks)
- π Retina-friendly (context scale-aware)
- π° Trivial to layer multiple shadows
- βοΈ Behind-the-scenes multi-layer caching
- π Debug optimized for high quality of life
- π€ Over 1000 correctness tests passing on macOS/windows
- π Compatible down to macOS 10.13 (progressive speedups on recent versions)
The goal: modern vector interfaces in JUCE (100s of shadows) without having to resort to deprecated solutions with lower quality of life (looking at you, OpenGL on macOS!).
AudioPluginHost.-.2023-12-11.15-trimmed.mp4
Melatonin Blur provides a 10-30x speedup over using Stack Blur alone.

On macOS, it depends on the built-in Accelerate framework.
On Windows, it optionally depends on the Intel IPP library. If IPP is not present, it will fall back to a JUCE FloatVectorOperations implementation for single channel (shadows, etc) and Gin's Stack Blur for ARGB.
Interested in how the blurring works? I wrote an in-depth article about re-implementing Stack Blur 15+ times.
The docs have outgrown a README file, visit the new documentation
There's all the usage information you could want over at the official docs
- Mars, for being my reliable rubber duck! Inner Shadow caching and compositing geometry broke my brain.
- Roland Rabien for JUCE Stack Blur workhorse via Gin.
- LukeM1 on the forums
for figuring out the
drawImageAt
optimization. - Ecstasy on the Discord for the motivation and feedback around stroked paths and default constructors.