Lottie grandchild fix v2 - #2802
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…ent layer is not rendered.
Replaced the shallow parent mapping with a topological traversal algorithm (buildAncestorTransforms) to accurately capture the entire hierarchy of ancestral transforms for each layer. Previously, Lottie layers completely discarded transforms generated past their immediate parent, breaking deep Lottie hierarchies. Providing the entire ancestral lineage as a sequential list natively preserves the top-down cascading render sequence, letting the RemoteCanvas apply each layer's intrinsic rotation, translation, and custom anchor points accurately. Additionally, wrapped the heavy hierarchical list allocations in a remember(animation.layers) block in LottieAnimation to prevent Garbage Collection churn and performance lags during recompositions.
yschimke
reviewed
Aug 17, 2026
yschimke
reviewed
Aug 17, 2026
yschimke
reviewed
Aug 17, 2026
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| composeRule.onNodeWithTag("Box").captureRoboImage(testName("_grandparent")) |
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It's hard from the test to reason about whether it's right or wrong. Can we either describe how to tell if it's working.
or alternatively, is there a way to make the image tell a story. Such as each layer being a some item like a circle with a number, and the transforms make each layer move out of the way, but without the grandparent, you won't see all 3?
1. Red Square (Root layer): Drawn in the top-left at [0, 0]. 2. Blue Square (Parent layer): Shifts its local child to the top-right at [96, 0]. 3. Green Square (Child layer): Shifts its local child down by [0, 96]. Because the Green Square is a child of the blue square, it inherits the [96, 0] translation and applies its own [0, 96] translation. This means if the Lottie engine correctly parses all 3 tiers of the hierarchy, the Green Square correctly lands in the bottom-right corner. If the bug was still present (where it ignorantly dropped the grandparent's transform), the Green Square would wrongly render in the bottom-left corner.
Preview ChangesWarning 1 preview(s) failed to render in this PR's render run. The diff below covers only the previews that produced a PNG. Changed (2 variant(s) across 2 function(s))
Render Failures (1 variant(s) across 1 function(s))The render task completed but produced no PNG for these previews. Common causes: Robolectric sandbox crash,
Unchanged (382 function(s), 564 variant(s))
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yschimke
reviewed
Aug 18, 2026
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| private fun buildAncestorTransforms(layers: List<Layer>): Map<Int, List<Transform>> { |
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After we land this, I might see if we can implement this as nested transforms, which is closer to the Compose way.
But not blocking for now.
yschimke
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Aug 18, 2026
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After fixing the screenshot
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Fix for #2795
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