arrow_paths.js

'use strict';

/**
 * All paths are tuned for maximum scalability of the arrowhead,
 * ie throughout arrowwidth=0.3..3 the head is joined smoothly
 * to the line, with the line coming from the left and ending at (0, 0).
 *
 * `backoff` is the distance to move the arrowhead and the end of the line,
 * in order that the arrowhead points to the desired place, either at
 * the tip of the arrow or (in the case of circle or square)
 * the center of the symbol.
 *
 * `noRotate`, if truthy, says that this arrowhead should not rotate with the
 * arrow. That's the case for squares, which should always be straight, and
 * circles, for which it's irrelevant.
 */

module.exports = [
    // no arrow
    {
        path: '',
        backoff: 0
    },
    // wide with flat back
    {
        path: 'M-2.4,-3V3L0.6,0Z',
        backoff: 0.6
    },
    // narrower with flat back
    {
        path: 'M-3.7,-2.5V2.5L1.3,0Z',
        backoff: 1.3
    },
    // barbed
    {
        path: 'M-4.45,-3L-1.65,-0.2V0.2L-4.45,3L1.55,0Z',
        backoff: 1.55
    },
    // wide line-drawn
    {
        path: 'M-2.2,-2.2L-0.2,-0.2V0.2L-2.2,2.2L-1.4,3L1.6,0L-1.4,-3Z',
        backoff: 1.6
    },
    // narrower line-drawn
    {
        path: 'M-4.4,-2.1L-0.6,-0.2V0.2L-4.4,2.1L-4,3L2,0L-4,-3Z',
        backoff: 2
    },
    // circle
    {
        path: 'M2,0A2,2 0 1,1 0,-2A2,2 0 0,1 2,0Z',
        backoff: 0,
        noRotate: true
    },
    // square
    {
        path: 'M2,2V-2H-2V2Z',
        backoff: 0,
        noRotate: true
    }
];