Timezone not respected in charts

[kihra1]

Expected Behavior

Charts would plot in same timezone as the data.

Actual Behavior

Charts are plotted in UTC, even though the source data was tz-aware of the form: 2023-06-15 08:30:00-05:00

[0sahil]

Any way to get the expected behaviour?

[kernc]

backtesting.py/backtesting/_plotting.py

Lines 209 to 210 in d4ec0ba

	df['datetime'] = df.index # Save original, maybe datetime index
	df = df.reset_index(drop=True)

backtesting.py/backtesting/_plotting.py

Lines 249 to 260 in d4ec0ba

	if is_datetime_index:
	fig_ohlc.xaxis.formatter = CustomJSTickFormatter(
	args=dict(axis=fig_ohlc.xaxis[0],
	formatter=DatetimeTickFormatter(days='%a, %d %b',
	months='%m/%Y'),
	source=source),
	code='''
	this.labels = this.labels || formatter.doFormat(ticks
	.map(i => source.data.datetime[i])
	.filter(t => t !== undefined));
	return this.labels[index] || "";
	''')

So we either need to convert df['datetime'] to real UTC, or fix DatetimeTickFormatter to additionally format "%z". 🤔