Created attachment 185577 [details] automatic steps vs maximal steps Open attached file. The shapes have a radial gradient with transition start (border) 50%. If Skia is enabled the border is not only outer but also inside the gradient. If Skia is disabled the shape looks the same as with maximal steps, which is the expected rendering. Disable anti-aliasing, otherwise you get moire effects in case of rendering with maximal steps.
Created attachment 185578 [details] Screenshot Skia enabled
Reproducible. Version: 7.6.0.0.alpha0+ (X86_64) / LibreOffice Community Build ID: ab20dba30769a5a52830220daa347772485db6a2 CPU threads: 4; OS: Windows 10.0 Build 19045; UI render: default; VCL: win Locale: es-ES (es_ES); UI: en-US Calc: CL threaded Jumbo
Anyway, what looks to me very problematic it's the affecting by the Antialiasing.
Also confirming, With Skia Vulka or Skia raster libs rendering, using an increment value for the area gradient it is not as smooth as the "auto" checkbox achieves. Checked at each of 16, 32, 64, 128 and 256 level gradient. CPU GDI rendering, or with CPU HA those gradient steps increase in smoothness through 256 increments, matching the "automatic" at about 128 steps. The Skia based rendering of the gradient steps also increase--but they do not smooth out. So at 256 steps, still noticeable moiré and coarseness to the gradient. Did similar for https://git.libreoffice.org/core/+/a46cb5dc607d1d1af402ff3e8fce731e7427854d%5E%21 for bug 137523 for the liner gradients need to be done for radial area gradients?
Seems related, or even a dupe to bug 151328 and its bisect to https://cgit.freedesktop.org/libreoffice/core/commit/?id=6965bb07bb33429a7663a3f3ebe58ed89c4327d9
(In reply to V Stuart Foote from comment #4 s/ bug 137523/ bug 136523