drawXLabel method
Implementation
void drawXLabel(CanvasRenderingContext2D ctx, int x, int y, DateTime date) {
ctx
..beginPath()
..moveTo(x, y)
..lineTo(x, y + style.dashLength)
..stroke();
var label = '??';
if (timeStep.endsWith('s')) {
label = '${date.minute}:${date.second}';
} else if (timeStep.endsWith('m')) {
label = formatHoursMinutes(date);
} else if (timeStep.endsWith('h')) {
label = formatHoursMinutes(date);
} else if (timeStep.endsWith('d')) {
label = formatDateHum(date);
}
ctx.fillText(label, x, y + style.xLabelIndent);
}