Function determineXAlign

src/plugins/plugin.tooltip.js:246–264

(chart, options, size, yAlign)

}

function determineXAlign(chart, options, size, yAlign) {
  const {x, width} = size;
  const {width: chartWidth, chartArea: {left, right}} = chart;
  let xAlign = 'center';

  if (yAlign === 'center') {
    xAlign = x <= (left + right) / 2 ? 'left' : 'right';
  } else if (x <= width / 2) {
    xAlign = 'left';
  } else if (x >= chartWidth - width / 2) {
    xAlign = 'right';
  }

  if (doesNotFitWithAlign(xAlign, chart, options, size)) {
    xAlign = 'center';
  }

  return xAlign;
}

/**
 * Helper to get the alignment of a tooltip given the size