Default bar width on date axes should be smarter
Nobody has claimed this yet.
- Dominant language
- Python
- Stars
- 18.8k
- Forks
- 2.8k
- Avg merge
- 16h 26m
- Merged PRs (30d)
- 21
Description
This is likely a similar issue to https://github.com/plotly/plotly.js/issues/6199
Plotly version: 6.2.0
Minimal Example
import plotly.graph_objects as go
import pandas as pd
import datetime
data = [
{"date": datetime.date(2025,7,20), "net_sales": 23.34, "gross_sales": 32.98},
{"date": datetime.date(2025,7,21), "net_sales": 45.21, "gross_sales": 68.12},
{"date": datetime.date(2025,7,22), "net_sales": 12.98, "gross_sales": 34.54},
{"date": datetime.date(2025,7,23), "net_sales": 41.32, "gross_sales": 45.32},
]
df = pd.DataFrame.from_records(data)
def make_figure(df, width=None):
fig = go.Figure()
fig.add_trace(go.Bar(
x=df['date'],
y=df['net_sales'],
xperiod=24*60*60*1000,
xperiod0=df['date'].min(),
xperiodalignment="middle"
))
fig.add_trace(go.Bar(
x=df['date'],
y=df['gross_sales'],
xperiod=24*60*60*1000,
xperiod0=df['date'].min(),
xperiodalignment="middle"
))
fig.update_layout(
xaxis={
'ticklabelmode': 'period',
'tickmode': 'auto',
'dtick': 24*60*60*1000,
'range': (df['date'].min(), df['date'].max() + datetime.timedelta(days=1))
})
fig.show(renderer="browser")
make_figure(df)
make_figure(df[0:1])
When plotting a bar chart of aggregated timeseries data, strange behaviour happens when there's only 1 data point or group. When there are multiple bars each bar is displayed as one would expect (first screenshot below), but when there's only a single data point the bar is invisible, and specifically the bar width is set to 1ms or 0.5px (second screenshot).
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start with the minimal Python example in the issue and compare the behavior with plotly.js issue #6199. Done means a single date point renders a visible bar with a sensible default width while multi-point bars retain their current behavior.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- data-visualization
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 38/100