Function makePadFn

src/plots/cartesian/autorange.js:211–246

(fullLayout, ax, max)

 * optional extrapad as 5% of the total axis length
 */
function makePadFn(fullLayout, ax, max) {
    // 5% padding for points that specify extrapad: true
    var extrappad = 0.05 * ax._length;

    var anchorAxis = ax._anchorAxis || {};

    if(
        (ax.ticklabelposition || '').indexOf('inside') !== -1 ||
        (anchorAxis.ticklabelposition || '').indexOf('inside') !== -1
    ) {
        var axReverse = ax.isReversed();
        if(!axReverse) {
            var rng = Lib.simpleMap(ax.range, ax.r2l);
            axReverse = rng[1] < rng[0];
        }
        if(axReverse) max = !max;
    }

    var zero = 0;
    if(!isLinked(fullLayout, ax._id)) {
        zero = padInsideLabelsOnAnchorAxis(fullLayout, ax, max);
    }
    extrappad = Math.max(zero, extrappad);

    // domain-constrained axes: base extrappad on the unconstrained
    // domain so it's consistent as the domain changes
    if((ax.constrain === 'domain') && ax._inputDomain) {
        extrappad *= (ax._inputDomain[1] - ax._inputDomain[0]) /
            (ax.domain[1] - ax.domain[0]);
    }

    return function getPad(pt) {
        if(pt.nopad) return 0;
        return pt.pad + (pt.extrapad ? extrappad : zero);
    };
}

var TEXTPAD = 3;