Function updateLabelLinePoints

src/label/labelGuideHelper.ts:338–401

(
    target: Element,
    labelLineModel: Model<LabelLineOption>
)

 * @param targetRect
 */
export function updateLabelLinePoints(
    target: Element,
    labelLineModel: Model<LabelLineOption>
) {
    if (!target) {
        return;
    }

    const labelLine = target.getTextGuideLine();
    const label = target.getTextContent();
    // Needs to create text guide in each charts.
    if (!(label && labelLine)) {
        return;
    }

    const labelGuideConfig = target.textGuideLineConfig || {};

    const points = [[0, 0], [0, 0], [0, 0]];

    const searchSpace = labelGuideConfig.candidates || DEFAULT_SEARCH_SPACE;
    const labelRect = label.getBoundingRect().clone();
    labelRect.applyTransform(label.getComputedTransform());

    let minDist = Infinity;
    const anchorPoint = labelGuideConfig.anchor;
    const targetTransform = target.getComputedTransform();
    const targetInversedTransform = targetTransform && invert([], targetTransform);
    const len = labelLineModel.get('length2') || 0;

    if (anchorPoint) {
        pt2.copy(anchorPoint);
    }
    for (let i = 0; i < searchSpace.length; i++) {
        const candidate = searchSpace[i];
        getCandidateAnchor(candidate, 0, labelRect, pt0, dir);
        Point.scaleAndAdd(pt1, pt0, dir, len);

        // Transform to target coord space.
        pt1.transform(targetInversedTransform);

        // Note: getBoundingRect will ensure the `path` being created.
        const boundingRect = target.getBoundingRect();
        const dist = anchorPoint ? anchorPoint.distance(pt1)
            : (target instanceof Path
                ? nearestPointOnPath(pt1, target.path, pt2)
                : nearestPointOnRect(pt1, boundingRect, pt2));

        // TODO pt2 is in the path
        if (dist < minDist) {
            minDist = dist;
            // Transform back to global space.
            pt1.transform(targetTransform);
            pt2.transform(targetTransform);

            pt2.toArray(points[0]);
            pt1.toArray(points[1]);
            pt0.toArray(points[2]);
        }