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CoarseTierMixin

Auto-generated from the @jbrowse/mobx-state-tree model in the source — see the developer guide for concepts. Built into JBrowse core. View source.

The zoomed-out tier a display draws in place of its detail past a threshold the display sets: MAF's summary bars. This mixin adds the swap decision, the per-region payloads and the read that fills them, through the shared fetch skeleton on a separate rotation, so the detail fetch's cancel never reaches it. While the tier is up the byte gate measures the coarse read, so its refusal is the banner and the detail fetch stands down.

The payloads live beside the foundation's per-region store, never in it, and the read records a span for the coarse tier alone: the two tiers fetch different widths of the same displayedRegionIndex, so one loadedRegions entry stamped by both would narrow the coarse span to the detail's on every zoom in and re-read the coarse adapter about an octave back out. The detail store keeps its entries under the tier — a display masks them where it draws, and zooming back in draws what it held.

A display states its tier through the hooks below: the adapter slot the source sits on, the threshold, what the read depends on beyond the span, and the read itself. Composed after MultiRegionDisplayMixin, so its displayPhase and svgReady are the ones types.compose keeps.

Volatiles

MemberDescription
coarseTier
ObservableMap<number, P>		The coarse payload by displayedRegionIndex, over the regions the last read was issued for. Cleared on chromosome navigation.
coarseTierRead
CoarseTierRead | undefined		What the held payloads were read over — the buffered regions and the read key — so a pan or a zoom inside them re-reads nothing. Undefined until a read lands.
coarseTierLoading
boolean

Getters

MemberDescription
coarseAdapterSlot
string | undefined		Overridable hook (default none): the slot on the track's adapter the coarse source sits in — summaryAdapter on MAF. With no slot there is no source and the tier never stands in.
coarseTierPastThreshold
boolean		Overridable hook (default false): the display's own line past which the tier stands in — a bp/px slot, a span floor.
coarseReadKey
unknown		Overridable hook (default ''): what the read depends on beyond its span and its adapter — a zoom bucket, the settings axis. A value compared structurally, so a held read whose key differs re-reads.
coarseSourceConfig
unknown		The coarse source's config, read off the live track config so a re-pointed adapter follows.
hasCoarseSource
boolean
coarseTierActive
boolean		Whether the coarse tier stands in for the detail right now.
coarseTierStandsIn
boolean		Whether the tier is standing in for the detail on screen right now: the tier's verdict over a measured view.
byteGateAdapterPath
ByteGateAdapterPath		RegionTooLargeMixin's hook: measure the adapter of the fetch that is about to run, so the estimate and the budget describe one file.
coarseTierIssueKey
{ adapter: (Record<string, unknown> & { type: string; }) | undefined; read: unknown; }
The whole key a read is held under: the coarse adapter and the display's own term.
fetchSuspended
boolean		MultiRegionDisplayMixin's hook: the coarse read is the measurement pass while the tier stands in, so the detail fetch has nothing to do.
displayPhase
DisplayPhase		The foundation's phase with the too-large banner swapped for the tier — see coarseTierDisplayPhase.
svgReady
boolean		The export gate under the same swap — see coarseTierSvgReady.

Actions

MemberDescription
setCoarseTier
(entries: CoarseTierEntry<P>[], read: CoarseTierRead) => void
clearCoarseTier
() => void
setCoarseTierLoading
(loading: boolean) => void
fetchCoarseTier
(_read: CoarseTierRead, _ctx: FetchContext) => Promise<CoarseTierResult<P>>
Overridable hook (no-op base): the coarse read over read.regions, returning one payload per region it covered, or a refusal. ctx is the skeleton's — its callRpc passes the signal and the status slot, and isStale guards any write the read makes for itself before it returns.