Calculate the height for containing the highest column

@name calculateLineHeight
@function
@param {Object[]} model is the line of data we want to calculate the height of
@param {Integer[]} columnWidths is size of each column
@returns {number} lineHeight
@private
function calculateLineHeight(model, columnWidths) {
        var padding = this.internal.__cell__.padding;
        var fontSize = this.internal.__cell__.table_font_size;
        var scaleFactor = this.internal.scaleFactor;

        return Object.keys(model)
            .map(function (value) {return typeof value === 'object' ? value.text : value})
            .map(function (value) { return this.splitTextToSize(value, columnWidths[value] - padding - padding) }, this)
            .map(function (value) { return this.getLineHeightFactor() * value.length * fontSize / scaleFactor + padding + padding }, this)
            .reduce(function (pv, cv) { return Math.max(pv, cv) }, 0);
    }