Migrate from 1.x

What changed

Volcano 2.0 is a major, intentionally breaking redesign. The 1.x root {}, section {}, and element {} DSL, tree classes, VolcanoBuilder, and Volcano() composable no longer exist. The replacement is a platform-neutral immutable HeatmapNode tree and the Heatmap composable.

Convert data at the boundary

Map a DTO or domain object to HeatmapNode once, outside composition. Use value for area and metric for the signed color indicator.

val root = HeatmapNode(
  id = "market",
  label = "Market",
  value = positions.sumOf { it.marketValue },
  children = positions.map { position ->
    HeatmapNode(
      id = position.symbol,
      label = position.symbol,
      value = position.marketValue,
      metric = position.dailyReturnPercent,
    )
  },
)

Replace the UI call

val state = rememberHeatmapState(root)
Heatmap(
  state = state,
  modifier = Modifier.fillMaxSize(),
  onLeafClick = { node -> openDetail(node.id) },
)

Add HeatmapBreadcrumb(state) and host Back handling when groups should drill down. Choose an optional image integration through logoContent; image loading is no longer implied by the base Compose artifact.

Release safely

Migrate one consumer at a time, keep the previous release pinned until its migration is verified, and do not attempt to use 1.x and 2.0 APIs together. Check Android Back, iOS safe area, Desktop resize, data aggregation, and custom colors before replacing a production dependency.