Function computeLabelSizes

static/plugins/chart.js/Chart.bundle.js:11228–11284

* Returns {width, height, offset} objects for the first, last, widest, highest tick * labels where offset indicates the anchor point offset from the top in pixels.

(ctx, tickFonts, ticks, caches)

 * labels where offset indicates the anchor point offset from the top in pixels.
 */
function computeLabelSizes(ctx, tickFonts, ticks, caches) {
	var length = ticks.length;
	var widths = [];
	var heights = [];
	var offsets = [];
	var widestLabelSize = 0;
	var highestLabelSize = 0;
	var i, j, jlen, label, tickFont, fontString, cache, lineHeight, width, height, nestedLabel, widest, highest;

	for (i = 0; i < length; ++i) {
		label = ticks[i].label;
		tickFont = ticks[i].major ? tickFonts.major : tickFonts.minor;
		ctx.font = fontString = tickFont.string;
		cache = caches[fontString] = caches[fontString] || {data: {}, gc: []};
		lineHeight = tickFont.lineHeight;
		width = height = 0;
		// Undefined labels and arrays should not be measured
		if (!isNullOrUndef(label) && !isArray(label)) {
			width = helpers$1.measureText(ctx, cache.data, cache.gc, width, label);
			height = lineHeight;
		} else if (isArray(label)) {
			// if it is an array let's measure each element
			for (j = 0, jlen = label.length; j < jlen; ++j) {
				nestedLabel = label[j];
				// Undefined labels and arrays should not be measured
				if (!isNullOrUndef(nestedLabel) && !isArray(nestedLabel)) {
					width = helpers$1.measureText(ctx, cache.data, cache.gc, width, nestedLabel);
					height += lineHeight;
				}
			}
		}
		widths.push(width);
		heights.push(height);
		offsets.push(lineHeight / 2);
		widestLabelSize = Math.max(width, widestLabelSize);
		highestLabelSize = Math.max(height, highestLabelSize);
	}
	garbageCollect(caches, length);

	widest = widths.indexOf(widestLabelSize);
	highest = heights.indexOf(highestLabelSize);

	function valueAt(idx) {
		return {
			width: widths[idx] || 0,
			height: heights[idx] || 0,
			offset: offsets[idx] || 0
		};
	}

	return {
		first: valueAt(0),
		last: valueAt(length - 1),
		widest: valueAt(widest),
		highest: valueAt(highest)
	};
}