Function pointToDataOneDimPrepareCtx

src/coord/matrix/Matrix.ts:495–572

(
    ctx: CtxPointToData,
    dimIdx: number,
    dims: MatrixDimPair,
    point: number[],
    clamp: MatrixClampOption | NullUndefined
)

const _tmpCtxPointToData: CtxPointToData = {x: null, y: null, point: []};

function pointToDataOneDimPrepareCtx(
    ctx: CtxPointToData,
    dimIdx: number,
    dims: MatrixDimPair,
    point: number[],
    clamp: MatrixClampOption | NullUndefined
) {
    const thisDim = dims[XY[dimIdx]];
    const otherDim = dims[XY[1 - dimIdx]];

    // Notice: considered cases: `matrix.x/y.show: false`, `matrix.x/y.data` is empty.
    // In this cases the `layout.xy` is on the edge and `layout.wh` is `0`; they still can be
    // use to calculate clampping.

    const bodyMaxUnit = thisDim.getUnitLayoutInfo(dimIdx, thisDim.getLocatorCount(dimIdx) - 1);
    const body0Unit = thisDim.getUnitLayoutInfo(dimIdx, 0);
    const cornerMinUnit = otherDim.getUnitLayoutInfo(dimIdx, -otherDim.getLocatorCount(dimIdx));
    const cornerMinus1Unit = otherDim.shouldShow() ? otherDim.getUnitLayoutInfo(dimIdx, -1) : null;

    let coord = ctx.point[dimIdx] = point[dimIdx]; // Transfer the oridinal coord.

    if (!body0Unit && !cornerMinus1Unit) {
        ctx[XY[dimIdx]] = CtxPointToDataAreaType.outside;
        return;
    }

    if (clamp === MatrixClampOption.body) {
        if (body0Unit) {
            ctx[XY[dimIdx]] = CtxPointToDataAreaType.inBody;
            coord = mathMin(bodyMaxUnit.xy + bodyMaxUnit.wh, mathMax(body0Unit.xy, coord));
            ctx.point[dimIdx] = coord;
        }
        else {
            // If clamp to body, the result must not be in header.
            ctx[XY[dimIdx]] = CtxPointToDataAreaType.outside;
        }
        return;
    }
    else if (clamp === MatrixClampOption.corner) {
        if (cornerMinus1Unit) {
            ctx[XY[dimIdx]] = CtxPointToDataAreaType.inCorner;
            coord = mathMin(cornerMinus1Unit.xy + cornerMinus1Unit.wh, mathMax(cornerMinUnit.xy, coord));
            ctx.point[dimIdx] = coord;
        }
        else {
            // If clamp to corner, the result must not be in body.
            ctx[XY[dimIdx]] = CtxPointToDataAreaType.outside;
        }
        return;
    }

    const pxLoc0 = body0Unit ? body0Unit.xy : cornerMinus1Unit ? cornerMinus1Unit.xy + cornerMinus1Unit.wh : NaN;
    const pxMin = cornerMinUnit ? cornerMinUnit.xy : pxLoc0;
    const pxMax = bodyMaxUnit ? bodyMaxUnit.xy + bodyMaxUnit.wh : pxLoc0;

    if (coord < pxMin) {
        if (!clamp) {
            // Quick pass for later calc, since mouse event on any place will enter this method if use `pointToData`.