core
Auto-generated from exported functions tagged #api in the source. See
imports and re-exports for how
to import these from a plugin.
buildColorRampLut
A 256-entry RGBA lookup table over sampleColorRamp, laid out as the 256x1
texture both GPU backends upload and the Canvas2D twins index — entry i is the
color at t = i / 255.
// type signature
(stops: readonly ColorRampStop[]) => Uint8Array<ArrayBuffer>relight
Move a color's OKLCH lightness by lightnessShift and scale its chroma, holding
its hue.
For extending a categorical palette past its length. Cycling a nine-color list over a 24-chromosome karyotype repeats the color outright; cycling it with a lightness shift per lap gives the hue back as a variant still told apart from the original — tab20's construction, which pairs a light and a dark of each hue.
SHIFT rather than a fixed lightness, and SCALE rather than a fixed chroma, because a categorical palette is uneven on purpose: category10's brown and its red are 5 degrees apart in hue and are told apart by chroma alone, so re-lighting both to one (lightness, chroma) makes them the same color. Keeping each color's own relative chroma keeps brown reading as brown.
In OKLCH rather than through lighten/darken, which work in sRGB, where the
same coefficient moves a yellow and a blue by visibly different amounts: a lap
has to read as one tone across the whole palette or it reads as noise.
// type signature
(color: string, lightnessShift: number, chromaScale?: number) => stringsampleColorRamp
The color at t in [0, 1] across a list of EVENLY SPACED stops, linearly
interpolated per channel. t is clamped, so the ends are the end stops rather
than an extrapolation past them, and a one-stop ramp is that stop everywhere.
// type signature
(stops: readonly ColorRampStop[], t: number) => ColorRampStopSessionPaletteProvider
Make JBrowse follow the host's light/dark state — the whole of it, in one mount:
<SessionPaletteProvider session={session} mode={myAppIsDark ? 'dark' : 'light'}>
{tracks}
</SessionPaletteProvider>A component rather than a documented pair of calls because the pair has a half
that can be left out with nothing to show for it. PaletteProvider is the name
a host reaches for, and it colors the React side alone; the session write is
what reaches the RPC worker, which bakes feature labels into the rendered image.
So a host that mounts only the provider gets light-mode labels on a dark page,
from a canvas whose every other pixel is right, and nothing errors. See
useSessionPalette for the mechanism.
The session is the only thing that resolves a palette here, so a host supplying
colors of its own mounts PaletteProvider directly instead.
// type signature
({ session, mode, children, }: { session: ThemeModeSession; mode: "dark" | "light"; children: ReactNode; }) => Element