jointjs/src/routers/oneSide.mjs

JavaScript diagramming library

import * as util from '../util/index.mjs';

// Routes the link always to/from a certain side
//
// Arguments:
//   padding ... gap between the element and the first vertex. :: Default 40.
//   side ... 'left' | 'right' | 'top' | 'bottom' :: Default 'bottom'.
//
export const oneSide = function(vertices, opt, linkView) {

    var side = opt.side || 'bottom';
    var padding = util.normalizeSides(opt.padding || 40);

    // LinkView contains cached source an target bboxes.
    // Note that those are Geometry rectangle objects.
    var sourceBBox = linkView.sourceBBox;
    var targetBBox = linkView.targetBBox;
    var sourcePoint = sourceBBox.center();
    var targetPoint = targetBBox.center();

    var coordinate, dimension, direction;

    switch (side) {
        case 'bottom':
            direction = 1;
            coordinate = 'y';
            dimension = 'height';
            break;
        case 'top':
            direction = -1;
            coordinate = 'y';
            dimension = 'height';
            break;
        case 'left':
            direction = -1;
            coordinate = 'x';
            dimension = 'width';
            break;
        case 'right':
            direction = 1;
            coordinate = 'x';
            dimension = 'width';
            break;
        default:
            throw new Error('Router: invalid side');
    }

    // move the points from the center of the element to outside of it.
    sourcePoint[coordinate] += direction * (sourceBBox[dimension] / 2 + padding[side]);
    targetPoint[coordinate] += direction * (targetBBox[dimension] / 2 + padding[side]);

    // make link orthogonal (at least the first and last vertex).
    if ((direction * (sourcePoint[coordinate] - targetPoint[coordinate])) > 0) {
        targetPoint[coordinate] = sourcePoint[coordinate];
    } else {
        sourcePoint[coordinate] = targetPoint[coordinate];
    }

    return [sourcePoint].concat(vertices, targetPoint);
};