Hi, For 3 months I worked on an improved alpha blending method in the Marlin renderer project (on github): https://github.com/bourgesl/marlin-renderer/tree/unsafe-dev
It is implemented as a pure-java experimental code that rewrite alpha compositing operations (SRC_OVER) to perform gamma-correction (sRGB profile) before/after any pixel operation to properly mix colors in RGB linear space. As dark shades looks then lighter, in particular for font or thin shapes (black over white), I implemented several correction algorithms based on luminance & contrast correction that adjusts alpha values. It is tricky as the ideal correction would require enlarging stroke width or polygon fills... but it would change coverage algebra= overlaps... that may need API enhancements at least. I forgave this direction as no simple & automatic solution exists. Finally I have 3 compositor modes: linear / hybrid / perceptual. See the latest Marlin renderer 0.9.5 EA release notes: https://github.com/bourgesl/marlin-renderer/releases/tag/v0_9_5_0_EA_b2 Visual comparison: https://bourgesl.github.io/gamma-correction/GRID_FONT.final/index.html It is only working up to now on buffered images (off-screen INT_ARGB) but the performance (java + unsafe) is now as good as the former C software loops. I wonder if: - there is any interest in improving java2d color handling in 2020 ? it is a behaviour change that must be discussed first. - how to proceed for a possible OpenJDK integration? Use java code like my hack or fix C macros / loops to use this new approach / maths ? - How to fix accelerated pipelines (opengl, directx, metal) too ? - who would help me ? Any comment or feedback on this topic ? Thanks, Laurent
