Timelines and calendars¶

Schedules, event sequences and daily values placed in time. Times are what the x scale takes: numbers on a linear scale, or dates, datetimes and ISO strings on a date scale (a panel with x=('2025-01-01', '2025-07-01') has one).

All values below are illustrative. Each snippet can be run independently with core Inklet; PNG preview generation additionally uses the render extra. Run a block from the repository root with .venv/bin/python; each block writes an SVG and PDF that can be opened without a notebook.

Gantt charts¶

gantt draws one bar per task from its start to its end, on the row its label names. A task that ends where it starts is a milestone, drawn as a diamond. groups= colours tasks by group, with one legend entry per group. List the rows in reverse so that the first task is at the top.

import inklet as i

rows = ['Launch', 'Review', 'Build', 'Design', 'Scope']
tasks = [('Scope', '2025-01-06', '2025-01-31', 'Scope'),
         ('Design', '2025-01-27', '2025-03-14', 'Design'),
         ('Build', '2025-03-03', '2025-05-30', 'Build'),
         ('Review', '2025-06-02', '2025-06-20', 'Review'),
         ('Launch', '2025-06-23', '2025-06-23')]
p = i.plot_spec(x=('2025-01-01', '2025-07-01'), y=rows, height=30, width=80)
p.gantt(tasks, groups=['Plan', 'Plan', 'Make', 'Check', 'Check'], labels=True)
p.axes().legend(side='top')
doc = i.document(width=100)
doc.add('gantt', p)
doc.save('gantt.svg', 'gantt.pdf')

An illustrative schedule. A label that does not fit inside its bar is written after it.

Event timelines¶

timeline draws events as labelled stems off a base line. Stems alternate above and below the line and move outward only as far as needed to keep the labels from overlapping. levels= sets the levels yourself.

import inklet as i

events = [('2020-03-11', 'Pandemic declared'), ('2020-12-08', 'First vaccine'),
          ('2021-05-01', 'Variant found'), ('2021-11-26', 'Omicron'),
          ('2022-05-01', 'Restrictions end'), ('2023-05-05', 'Emergency over'),
          ('2024-06-01', 'Review')]
p = i.plot_spec(x=('2020-01-01', '2025-01-01'), height=26, width=90)
p.timeline(events)
p.axis('bottom')
doc = i.document(width=100)
doc.add('timeline', p)
doc.save('timeline.svg', 'timeline.pdf')

Illustrative events. The base line runs through the middle of the panel, or at the y value at=; line=False leaves it out.

Calendar heatmaps¶

calendar draws one square per day, with one column per week and one row per weekday. Month names are written above and every other weekday at the left. Days in the range without a value are drawn pale. Colours use the matrix ramps, so colorbar() explains them. Use calendar_weeks to size the panel.

import inklet as i
import datetime as dt
import math

start, end = dt.date(2025, 1, 1), dt.date(2025, 12, 31)
steps = {}
for d in range(365):
    day = start + dt.timedelta(days=d)
    if d % 17 != 3:
        steps[day] = 6000 + 3000 * math.sin(d / 20) + (2500 if day.weekday() >= 5 else 0)
weeks = i.plot.calendar_weeks(start, end)
p = i.plot_spec(width=weeks * 2.2, height=7 * 2.2)
p.calendar(steps, start=start, end=end)
p.colorbar(side='bottom', label='Steps per day')
doc = i.document(width=130)
doc.add('calendar', p)
doc.save('calendar.svg', 'calendar.pdf')

Simulated step counts. The pale squares are days with no value.

Next steps¶

Compare plot types, configure axes and scales, or arrange several panels. For exact options, see the API.