fix: Avoid desync between start and end (outer and inner) radial gradient circles #3112
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…ient circles Due to the way `_mdf` (modified) flags are checked in `SVGElementsRenderer.renderGradient()`, it's possible that the `fx` and `fy` components of a radial gradient, defining its "inner" circle (used for highlights via `.h` and `.a` members of a `gf` shape element in the Lottie JSON), fall out of sync with `cx` and `cy` which define its outer circle. In particular, the branch which sets `fx`/`fy` triggers only when the gradient end point changes, but then sets `fx` and `fy` based on a calculation that involves both the start and end points. Therefore, if the start point of a gradient ever changes without a corresponding change in the end point, the `cx`/`cy` value will be updated but not the `fx`/`fy` value, causing visual artifacts.
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Due to the way
_mdf(modified) flags are checked inSVGElementsRenderer.renderGradient(), it's possible that thefxandfycomponents of a radial gradient, defining its "inner" circle (used for highlights via.hand.amembers of agfshape element in the Lottie JSON), fall out of sync withcxandcywhich define its outer circle.In particular, the branch which sets
fx/fytriggers only when the gradient end point changes, but then setsfxandfybased on a calculation that involves both the start and end points. Therefore, if the start point of a gradient ever changes without a corresponding change in the end point, thecx/cyvalue will be updated but not thefx/fyvalue, causing visual artifacts.File exhibiting issue: radial-gradient-repro.json
Current rendering:
After fix:
