Dash_tooltip 0.3.5

A tooltip functionality for Dash.

Dash Tooltip

A module to add interactive editable tooltips to your Dash applications. Inspired by mplcursors and Matlab's datatip.

Installation

You can download the dash_tooltip.py module and place it in your working directory.

Basic Usage

import numpy as np
import plotly.express as px
from dash import Dash, dcc, html
from dash.dependencies import Input, Output
from dash_tooltip import tooltip

# Sample Data
np.random.seed(20)
y1 = np.random.normal(0, 10, 50)
x1 = np.arange(0, 50)
fig1 = px.scatter(x=x1, y=y1)
fig1.update_layout(title_text="Editable Title", title_x=0.5)

app1 = Dash(__name__)

#makes graph items, including tooltips editable
app1.layout = html.Div([
    dcc.Graph(
        id='graph1',
        figure=fig1,
        config={
            'editable': True,
            'edits': {
                'shapePosition': True,
                'annotationPosition': True
            }
        }
    )
])

# Add the tooltip functionality to the app
tooltip(app1)

Click on data points to add tooltips. If dcc.Graph is configured editatble, tolltips:

• can be dragged around
• text can be edited on click
• can be deleted: click, delete text, enter. In some occasions a tooltip arrow may remain due to a Dash bug (clientside_callback not firing). In this cas, click near arrow end (mouse cursor changes to pointer), enter some text and repeat deletion and enter.

Advanced Usage

If you want to customize the tooltips, hover templates, and more:

import pandas as pd
import numpy as np
import plotly.express as px
from dash import Dash, dcc, html
from dash.dependencies import Input, Output
from dash_tooltip import tooltip

# Generate random time series data
date_rng = pd.date_range(start='2020-01-01', end='2020-12-31', freq='h')
ts1 = pd.Series(np.random.randn(len(date_rng)), index=date_rng)
ts2 = pd.Series(np.random.randn(len(date_rng)), index=date_rng)
df = pd.DataFrame({'Time Series 1': ts1, 'Time Series 2': ts2})

template = "x: %{x}<br>y: %{y:.2f}<br>ID: %{pointNumber}<br>name: %{customdata[0]}<br>unit: %{customdata[1]}"
fig10 = px.line(df, x=df.index, y=df.columns, title="Time Series Plot")

for i, trace in enumerate(fig10.data):
    trace.customdata = np.column_stack((np.repeat(df.columns[i], len(df)), np.repeat('#{}'.format(i+1), len(df))))
    trace.hovertemplate = template

app10 = Dash(__name__)

app10.layout = html.Div([
    dcc.Graph(
        id="graph-id",
        figure=fig10,
        config={
            'editable': True,
            'edits': {
                'shapePosition': True,
                'annotationPosition': True
            }
        }
    )
])

tooltip(app10, graph_ids=["graph-id"], template=template, debug=True)

Tooltip Templates with Formatting

Tooltips can be formatted using templates similar to Plotly's hovertemplates. The tooltip template allows custom formatting and the inclusion of text and values.

For example, you can use a template like "x: %{x:.2f}<br>y: %{y:.2f}" to display the x and y values with two decimal places.

Refer to Plotly’s documentation on hover text and formatting for more details on how to construct and customize your tooltip templates.

Custom Styling

custom_style = {
        "font": {"size": 12, "color":"red"},
        "arrowcolor": "red",
        'arrow_size': 5,
        # ... any other customization
    }
tooltip(app10, style=custom_style, graph_ids=["graph-id"], template=template, debug=True)

For more examples, refer to the provided dash_tooltip_demo.py or its Jupyter counterpart dash_tooltip_demo.ipynb.

Handling Log Axes

Due to a long-standing bug in Plotly (see Plotly Issue #2580), annotations (fig.add_annotation) may not be placed correctly on log-scaled axes. The dash_tooltip module provides an option to automatically correct the tooltip placement on log-scaled axes via the apply_log_fix argument in the tooltip function. By default, apply_log_fix is set to True to enable the fix.

Debugging

If you encounter any issues or unexpected behaviors, enable the debug mode by setting the debug argument of the tooltip function to True. The log outputs will be written to dash_app.log in the directory where your script or application is located.

License

This project is licensed under the MIT License. See the LICENSE file for details.

Acknowledgements

• Inspired by mplcursors and Matlab's datatip.