Method Detail

• ThreeZoneLayout

  @Composable() final static Unit ThreeZoneLayout(List<ContentBlock> blocks, Function1<ContentBlock, Unit> renderBlock, Modifier modifier, Alignment.Horizontal topAlignment, Alignment.Horizontal centerAlignment, Alignment.Horizontal bottomAlignment)

  SPEC-070-A I.17 — ThreeZoneLayout partitions a step's ContentBlock list into three vertical zones — top, center, bottom — and spaces them with weighted spacers so each zone retains its visual region as the screen height changes.

  Mirrors iOS Onboarding/ThreeZoneStepLayout.swift:109-122. Empty zones collapse so the renderer doesn't introduce phantom whitespace; non-empty zones each carry a weight of 1 by default, matching iOS Layout's "GeometryReader { proxy in VStack { … } }" partition.

  The zone for each block is decided by:

  • block.zone (explicit "top" / "center" / "bottom"),

  • else block.vertical_align (legacy field, same vocabulary),

  • else default to "center".

  Hosts use this when step.layout == "three_zone" (or whatever flag the outer renderer chooses). For non-three_zone steps the existing BlockBasedStepView continues to render inline.

  Parameters:

  blocks - All step blocks (already filtered for visibility).

  renderBlock - Callback the layout invokes for each block — keeps rendering decisions in the host (style, action wiring) while this layout owns only the zoning.

  topAlignment - Alignment within the top zone (default = TopCenter).

  centerAlignment - Alignment within the center zone (default = Center).

  bottomAlignment - Alignment within the bottom zone (default = BottomCenter).