Vertical gradient across the band, graded between two prices rather than two pixel rows.

The stops are anchored in PRICE, not in pixels, because that is what the shading is claiming: a band graded from its 70 level down to its 30 means those levels, and a viewport-relative gradient would slide off them the moment the pane is panned or the scale re-fits.

interface FillGradient {
    bottomColor: string;
    bottomValue?: number;
    topColor: string;
    topValue?: number;
}

Properties

bottomColor: string
bottomValue?: number

Price the bottom stop sits at. Omitted: the band's own lowest value.

topColor: string
topValue?: number

Price the top stop sits at. Omitted: the band's own highest value.