Zoom-in (inset) plot example in plotly.py

inset_plotly.py

import math
import numpy as np
import plotly.graph_objects as go
import plotly.io as pio

# plotly figure
pio.templates.default = "plotly_white"
fig = go.Figure()

# damped oscillation
def fn(x):
    return math.exp(-0.05 * x) * (1 - math.cos(x))

n_samples = 1000

# main plot
x0 = 0
x1 = 100
xs = np.linspace(x0, x1, n_samples)
ys = [fn(x) for x in xs]
y0 = 0
y1 = max(ys)

fig.add_trace(go.Scatter(x=xs,
                         y=ys,
                         mode="lines",
                         line_color="rgb(100,150,250)"))

# area to zoom in
zoom_x0 = 60
zoom_x1 = 90
zoom_xs = np.linspace(zoom_x0, zoom_x1, n_samples)
zoom_ys = [fn(x) for x in zoom_xs]
zoom_y0 = 0
zoom_y1 = max(zoom_ys)

fig.add_trace(go.Scatter(x=zoom_xs,
                         y=zoom_ys,
                         mode="lines",
                         xaxis="x2",
                         yaxis="y2",
                         line_color="rgb(100,150,250)"))

# position of the zoomed area
subplot_x0 = 0.4
subplot_x1 = 0.95
subplot_y0 = 0.5
subplot_y1 = 0.95

# shapes to indicate which area is zoomed in
fig.add_shape(
    type="rect",
    x0=zoom_x0,
    y0=zoom_y0,
    x1=zoom_x1,
    y1=zoom_y1,
    fillcolor="rgba(100,150,250,0.3)",
    line_width=1,
)
fig.add_shape(
    type="line",
    x0=zoom_x0,
    y0=zoom_y1,
    x1=x0 + (x1 - x0) * subplot_x0,
    y1=y0 + (y1 - y0) * subplot_y0,
    line_width=1,
    line_dash="dot",
)
fig.add_shape(
    type="line",
    x0=zoom_x1,
    y0=zoom_y1,
    x1=x0 + (x1 - x0) * subplot_x1,
    y1=y0 + (y1 - y0) * subplot_y0,
    line_width=1,
    line_dash="dot",
)

# layout
fig.update_xaxes(
    title_text="t",
    linecolor="black",
    ticks="outside",
    range=[x0, x1],
)
fig.update_yaxes(
    title_text="amplitude",
    linecolor="black",
    ticks="outside",
    range=[y0, y1],
)

fig.update_layout(
    width=500,
    height=300,
    margin=dict(l=0, r=0, b=0, t=0),
    font_size=16,
    showlegend=False,
    xaxis2=dict(
        domain=[subplot_x0, subplot_x1],
        anchor="y2",
        linecolor="black",
        mirror=True,
        ticks="outside",
        range=[zoom_x0, zoom_x1],
    ),
    yaxis2=dict(
        domain=[subplot_y0, subplot_y1],
        anchor="x2",
        linecolor="black",
        mirror=True,
        ticks="outside",
        rangemode="tozero",
        range=[zoom_y0, zoom_y1],
    ),
)

fig.show()

Output: