Lottie4J 1.2.5

2026-07-09 by Frank Delporte

1.2.5 Is Out With Many Rendering Accuracy Fixes

Lottie4J 1.2.5 is released, and it’s almost entirely the payoff from the work described in Closing the Visual Gap with the Official Lottie Webplayer: once the comparison test suite could point at the exact frame and pixel where the JavaFX player drifted from the reference renderer, a batch of concrete rendering bugs became easy to find and fix.

Highlights:

  • Fixed matte type handling (tt:2 = INVERTED_ALPHA).
  • Merged gradient alpha and color stops at the union of offsets, and added linear-RGB gradient stop densification, for more accurate gradient rendering.
  • Fixed text-layer color handling and added support for animated text color.
  • Fixed blend-mode offscreen buffer sizing (ceiling instead of truncating).
  • Improved Gaussian blur accuracy.
  • Ported lottie-web’s BezierEaser byte-for-byte into a shared core.helper.BezierEasing, improving easing fidelity.
  • Extracted pixel-level matte composition into a testable static helper, with further correctness improvements.
  • Migrated the WebView reference renderer used in comparison tests from lottie-web to dotlottie-wc (thorvg).

None of this would have been findable without the frame-by-frame diffing pipeline built in the previous post — that’s the part worth reading if you want the “why” behind these fixes rather than just the “what”.

See the full changelog for every change, or the GitHub diff between 1.2.4 and 1.2.5.