Function computeTextDimensions

src/components/legend/draw.js:744–832

(g, gd, legendObj, aTitle)

}

function computeTextDimensions(g, gd, legendObj, aTitle) {
    var legendItem = g.data()[0][0];
    var showlegend = legendItem && legendItem.trace.showlegend;
    if (Array.isArray(showlegend)) {
        showlegend = showlegend[legendItem.i] !== false;
    }
    if(!legendObj._inHover && legendItem && !showlegend) {
        g.remove();
        return;
    }

    var mathjaxGroup = g.select('g[class*=math-group]');
    var mathjaxNode = mathjaxGroup.node();

    var legendId = helpers.getId(legendObj);
    if(!legendObj) {
        legendObj = gd._fullLayout[legendId];
    }
    var bw = legendObj.borderwidth;
    var font;
    if(aTitle === MAIN_TITLE) {
        font = legendObj.title.font;
    } else if(legendItem.groupTitle) {
        font = legendItem.groupTitle.font;
    } else {
        font = legendObj.font;
    }
    var lineHeight = font.size * LINE_SPACING;
    var height, width;

    if(mathjaxNode) {
        var mathjaxBB = Drawing.bBox(mathjaxNode);

        height = mathjaxBB.height;
        width = mathjaxBB.width;

        if(aTitle === MAIN_TITLE) {
            Drawing.setTranslate(mathjaxGroup, bw, bw + height * 0.75);
        } else { // legend item
            Drawing.setTranslate(mathjaxGroup, 0, height * 0.25);
        }
    } else {
        var cls = '.' + legendId + (
            aTitle === MAIN_TITLE ? 'title' : ''
        ) + 'text';

        var textEl = g.select(cls);

        var textLines = svgTextUtils.lineCount(textEl);
        var textNode = textEl.node();

        height = lineHeight * textLines;
        width = textNode ? Drawing.bBox(textNode).width : 0;

        // approximation to height offset to center the font
        // to avoid getBoundingClientRect
        if(aTitle === MAIN_TITLE) {
            if(legendObj.title.side === 'left') {