Function shiftPosition

src/components/annotations/draw.js:74–92

(axa, dAx, axLetter, gs, options)

// axDomainRef: if true and axa defined, draws relative to axis domain,
// otherwise draws relative to data (if axa defined) or paper (if not).
function shiftPosition(axa, dAx, axLetter, gs, options) {
    var optAx = options[axLetter];
    var axRef = options[axLetter + 'ref'];
    var vertical = axLetter.indexOf('y') !== -1;
    var axDomainRef = Axes.getRefType(axRef) === 'domain';
    var gsDim = vertical ? gs.h : gs.w;
    if(axa) {
        if(axDomainRef) {
            // here optAx normalized to length of axis (e.g., normally in range
            // 0 to 1). But dAx is in pixels. So we normalize dAx to length of
            // axis before doing the math.
            return optAx + (vertical ? -dAx : dAx) / axa._length;
        } else {
            return axa.p2r(axa.r2p(optAx) + dAx);
        }
    } else {
        return optAx + (vertical ? -dAx : dAx) / gsDim;
    }
}

/**
 * drawRaw: draw a single annotation, potentially with modifications