GlobalFetchMixin

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 foundation for a display holding a single global (non-regional) dataset: HiC's contact matrix, the LD triangle, multi-way synteny's lanes.

Composes:

RegionTooLargeMixin (regionTooLarge, force-load, …)
RenderLifecycleMixin (attachRenderingBackend, renderNow, renderError, …)
KeyedFetchMixin (FetchMixin's runFetch, cancelFetch, isLoading, error, statusMessage, fetchGeneration, plus the currentFetchKey / loadedFetchKey freshness pair the comparative family composes too)

What is left here is what only an LGV display can say: the hosting RegionHost, the static-block signature every viewSignature in this family starts from, and the readiness getters that read the view — viewportEmpty, canRender, paintInert, svgReady, displayPhase.

Installs no autoruns — each display owns its fetch trigger, sharing the installGlobalFetchAutorun skeleton, to which it supplies only its own prepare / run / commit phases.

Each section ends with the members a composed model contributes, linked to the page that documents them.

Volatiles

20 inherited volatiles from 4 models

From RegionTooLargeMixin: forceLoadTrack, byteEstimate, gateMeasuredViewportKey

From RenderLifecycleMixin: canvasDrawn, paintCount, currentRenderingBackend, renderTick, autorunsInstalled, renderError, offScreen

From KeyedFetchMixin: loadedFetchKey

From FetchMixin: activeSignal, fetchGeneration, reloadCounter, statusWindow, error, statusMessage, statusProgress, fetchCanceled, fetchRotation

Getters

Member	Description
host `RegionHost`	The hosting view as the `RegionHost` contract — see `containingHost` for the cast it owns, why the name is `host` and not `view`, and why both foundations still declare the name over one body.
staticBlockSignature `string \| undefined`	The static-block set as a signature, or `undefined` before the view is measured — the building block every `viewSignature` in this family starts from. Multi-way synteny is exactly this; HiC appends its resolution. Declared here so the initialized gate is spelled once.
dynamicBlockSignature `string \| undefined`	The same over `dynamicBlocks`, for a display whose fetch window is the live viewport rather than the snapped block set (LD).
viewportEmpty `boolean`	No content block is on screen, so this display has nothing to fetch and nothing to paint — see `viewportEmpty.ts` for the one viewport that reaches it, how narrow that is, and why the state still has to be terminal rather than a permanent scrim. Both foundations declare it over that one expression, the same way they each declare `host` and `paintInert`.
canRender `boolean`	Overrides `RenderLifecycleMixin`'s default-true hook with the LGV precondition both foundations share — see `foundationCanRender`.
rendersCanvas `boolean`	Fills `RenderLifecycleMixin`'s hook off `fetchInert`: a display that will never fetch here shows a placeholder where its canvas would be, so `painted` and the pre-first-paint scrim term stop waiting on a paint that cannot come. Sequence and LD each carried this as a second override beside `fetchInert`, always its negation.
paintInert `boolean`	Fills `RenderLifecycleMixin`'s `paintInert` hook — see there for why a failed fetch has to read as finished to the consumers outside the display, and `foundationPaintInert` for the second such state and why both fetch families answer it through one function. Overridable, as the hook is: a display with a third inert state of its own says so here.
svgReady `boolean`	Policy single-sourced in `computeSvgReady`; this family supplies only the freshness half, which `foundationSvgReady` reads as `dataCurrent` or the vacuous currency of `viewportEmpty`. Note it requires the dataset to actually be current, NOT merely "not currently fetching": the fetch trigger is a debounced `afterAttach` autorun, so at export time `isLoading` can still be false with no data yet — a `displayPhase !== 'loading'` test would then capture an empty render. Never gates on `canvasDrawn`, which an off-screen export never sets. Off-screen renderers gate on it via `awaitSvgReady(model)`.
displayPhase `DisplayPhase`	The display's mutually-exclusive visual state, mapped in `foundationDisplayPhase` — every foundation calls it and supplies only its staleness argument, so a term added to `computeActivityPhase` reaches all of them without being wired twice. This family's argument is the constant `true`, deliberately: a global display keeps the last frame up through a refetch (worker output is genomic, so the stale frame draws correctly under the live view transform), so a pan or zoom shows no scrim beyond the `isLoading` window. The pre-first-paint scrim it does want — the gap between mount and `isLoading` going true, which on HiC is the `CoreGetInfo` round trip its first fetch waits on — is `computeActivityPhase`'s shared `rendersCanvas && !canvasDrawn` term, not anything this family spells out.