Dartt

Dartt is a tool for generating Gantt charts from Ruby code.

You can describe your project tasks and milestones with a Ruby internal DSL and generate Gantt chart images. It focuses on using simple dependencies and task lengths for defining everything, and most of the the chart options and layout are configurable.

Charts are generated as SVG images.

For example, this code:

require 'dartt'
require 'date'

Dartt.svg "The Schedule", Date.new(2021, 1, 4), Date.new(2021, 3, 29), "svg-chart" do
    section "Phase 1"
    first_task = task "First Task", start: Date.new(2021, 1, 4), days: 20
    second_task = task "Second Task", after: first_task, days: 20
    milestone "Phase 1 Comlete", after: second_task

    section "Phase 2"
    final_task = task "Final Task", after: second_task, days: 10
    milestone "Phase 2 Complete", after: final_task
end

Produces this chart:

Installation

Add this line to your application's Gemfile:

gem 'dartt'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install dartt

Usage

Creating charts

Create charts by requiring the dartt module and using the svg function of the module.

Dartt.svg (title, start_date, end_date, filename) 

The arguments to the svg function are:

• title - The title of the chart.
• start_date - The first day of the chart.
• end_date - The last day of the chart.
• filename - The name of the svg file to create (do not include the .svg extension).

Note: The dates are provided as Ruby Date objects, so you will need to require 'date' as well.

The svg function takes a block will contain the chart.

Dartt.svg "The Schedule", Date.new(2021, 1, 4), Date.new(2021, 3, 29), "svg-chart" do 
  # Define your tasks and milestones here.
end

All tasks and milestones drawn in the order in which they are listed in the chart.

Tasks

Tasks are created using the task command. The task command takes a variety of arguments to specify the start and end of a task. This allows you to define tasks relative to other tasks, e.g. before or after other tasks.

Some ways to define tasks include:

Definition	Example
A start date and duration	task "Task 1", start: Date.new(2021, 1, 6), days: 3
A start date and an end date	task "Task 2", start: Date.new(2021, 1, 6), end: Date.new(2021, 1, 8)
An end date and duration	task "Task 3", end: Date.new(2021, 1, 8), days: 3
After another task (with duration)	task "Task 4", after: some_other_task, days: 3
After another task (with end date)	task "Task 4", after: some_other_task, end: Date.new(2021, 1, 8)
Before another task (with duration)	task "Task 5", before: some_other_task, days: 3
Before another task (with start date)	task "Task 5", start: Date.new(2021, 1, 6), before: some_other_task, days: 3

Milestones

Milestones are defined with the milestone command.

Milestones can either be added with a specific date:

milestone "v1.0 Delivery", Date.new(2021, 1, 8)

Or after some other task:

milestone "v1.0 Delivery", after: some_other_task

Sections

Sections group tasks and milestones together. Sections are created with the section command. All tasks and milestones added after defining a section are added to it until a new section is added.

section "Section 1"
# All tasks and milestones added here are included in section 1.

section "Section 2"
# All tasks and milestones added here are included in section 2.

A note on dates

All dates are "inclusive," for example:

• A task which begins on Jan 4 and lasts 2 days will end on Jan 5.
• A task with begins on Jan 4 and ends on Jan 5 has a duration of 2 days.

When these tasks are drawn on the chart they will occupy two days worth of space.

The "end date" of both of these tasks is Jan 5. If you started a new task on this end date, both tasks would overlap for a day (on Jan 5). When defining a task relatively (with before: or after:) the relative task is defined such that it does not overlap with the other task.

Weekends

By default, weekends are not included in any scheduling. When calculating durations, weekends are skipped. If a task is defined with a date that falls on a weekend, it is moved to the next weekday.

Custom configuration

Individual configuration settings can be overriden by providing a custom configuration hash. Only the settings that you want to change need to be included.

For example, change the color of title like this:

custom_config = {
  title => {
    :font_color => "pink"
  }
}

Dartt.svg "Title", Date.new(2021, 1, 4), Date.new(2021, 3, 29), "filename", config: custom_config do
 # Tasks and milestones go here.
end

Custom styling with tags

Create custom tags by adding them to a custom configuration:

custom_config = {
  :tags => {
    :red => {
      :font_color => "white",
      :fill => "red",
      :line => "black",
    },
    :blue => {
      :font_color => "blue",
      :fill => "white",
      :line => "blue",
    }
  }
}

Then you can tag a task or milestone and it will get the tag-specific styling:

t = task "A Task", :red, start: Date.new(2021, 1, 4), days: 20
milestone "Task Complete", :blue, after: t

Default configuration

This is the default configuration, and each of these can be overridden.

{
  :width => 1920,
  :height => 1080,
  :title => {
    :height => 108,
    :font_color => "#003470",
  },
  :section => {
    :width => 300,
    :margin => 20,
    :color_1 => '#FFFDA2',
    :color_1_opacity => 0.4,
    :color_2 => 'white',
    :color_2_opacity => 0.0,
  },
  :axis => {
    :height => 80,
    :week_height => 32,
    :fill_color => '#D7D7D7',
    :line_color => 'white',
    :line_weight => 2,
    :weekend_color => '#E0E0E0',
    :grid_line_color => '#C1C1C1',
  },
  :task => {
    :height => 40,
    :vertical_margin => 3,
    :horizontal_margin => 0,
    :rounding => 5,
    :font_size => 20,
    :font_color => "#003470",
    :fill => "#77B7FF",
    :line => "#0D57AB",
    :line_weight => 2,
  },
  :milestone => {
    :height => 40,
    :vertical_margin => 2,
    :rounding => 4,
    :font_size => 20,
    :font_color => "#003470",
    :fill => "#77B7FF",
    :line => "#0D57AB",
    :line_weight => 2,
  },
  :tags => {
    :done => {
      :font_color => "#505050",
      :fill => "#d5d5d5",
      :line => "#505050",
    },
  },
}

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/[USERNAME]/dartt. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.

License

The gem is available as open source under the terms of the MIT License.

Code of Conduct

Everyone interacting in the Dartt project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.

TODO

• If you start a task before another one, draw it above that one.
• Automatic chart sizing.
• Reference chart start/end for task dates.
• Allow dependencies on more than one task.
• Dates can be specified as strings instead of objects.
• Individual day highlighting.
• Shift text to left at end of chart.
• Built in PNG conversion.

Errors to handle

• Tasks placed outside chart dates.
• Task and milestone title run off the end of the chart.