Usage
=====

GanttChart allows the creation of Gantt charts.

Tasks
-----

Tasks are created with a title, an end or duration, and optionally an id (one is auto-generated if not given).
If the task has an end date it is either a specific date or the string `until id`
where *id* is the id of the task this task is active until.
If the task has a duration it is specified as *nt* where *n* is an integer
and *t* is a letter indicating the duration unit, e.g. *d* for *days*.

By default, a task starts at the time the previous task ends.
If this is not the case, the start can be specified as a date or the string `after id`
where *id* is the id of the task this task starts after.

Tasks can be given tags to indicate their status.

Milestones
----------

Milestones are created with a title, a start, a duration, and optionally an id (one is auto-generated if not given).
The actual point of the milestone on the diagram is *(start + duration)/2*.

Vertical Markers
----------------

Vertical markers are created with a title, a start, a duration, and optionally an id (one is auto-generated if not given).
The actual point of the vertical marker on the diagram is *start + duration/2*.
Vertical markers are purely visual reference points.

Sections
--------

Sections allow grouping of tasks and milestones; sections are created with a title and tasks and milestones are added.

GanttChart
----------

Tasks, milestones, vertical markers, and sections are added to a GanttChart instance.

GanttChart allows days of the week, e.g. weekends, to be excluded from task duration calculations,
the days that make up a weekend, the input date format, and output date to be specified.

Example
-------

PHP
+++

.. code-block:: php

    echo Mermaid::create(GanttChart::class)
        ->withTitle('Adding GANTT diagram functionality to mermaid')
        ->withExcludes(Exclude::weekends)
        ->withItem(
            (new Section('A section'))
                ->withItem(
                    (new Task('Completed task', '2014-01-08', 'des1'))
                        ->withStart('2014-01-06')
                        ->withTag(Tag::done)
                    ,
                    (new Task('Active task', '3d', 'des2'))
                        ->withStart('2014-01-09')
                        ->withTag(Tag::active)
                    ,
                    (new Task('Future task', '5d', 'des3'))
                        ->withStart('after des2')
                    ,
                    (new Task('Future task2', '5d', 'des4'))
                        ->withStart('after des3')
                )
            ,
            (new Section('Critical tasks'))
                ->withItem(
                    (new Task('Completed task in the critical line', '24h'))
                        ->withStart('2014-01-06')
                        ->withTag(Tag::critical, Tag::done)
                    ,
                    (new Task('Implement parser and jison', '2d'))
                        ->withStart('after des1')
                        ->withTag(Tag::critical, Tag::done)
                    ,
                    (new Task('Create tests for parser', '3d'))
                        ->withTag(Tag::critical, Tag::active)
                    ,
                    (new Task('Future task in critical line', '5d'))
                        ->withTag(Tag::critical)
                    ,
                    new Task('Create tests for renderer', '2d'),
                    new Task('Add to mermaid', 'until isadded'),
                    new Milestone('Functionality added', '2014-01-25', '0d', 'isadded')
                )
            ,
            (new Section('Documentation'))
                ->withItem(
                    (new Task('Describe gantt syntax', '3d', 'a1'))
                        ->withStart('after des1')
                        ->withTag(Tag::active)
                    ,
                    (new Task('Add gantt diagram to demo page', '20h'))
                        ->withStart('after a1')
                    ,
                    (new Task('Add another diagram to demo page', '48h', 'doc1'))
                        ->withStart('after a1')
                )
            ,
            (new Section('Last section'))
                ->withItem(
                    (new Task('Describe gantt syntax', '3d'))
                        ->withStart('after doc1'),
                    new Task('Add gantt diagram to demo page', '20h'),
                    new Task('Add another diagram to demo page', '48h')
                )
        )
        ->render()
    ;

Generated Mermaid
+++++++++++++++++

.. code-block:: html

    <pre class="mermaid">
    gantt
      title Adding GANTT diagram functionality to mermaid
      dateFormat YYYY-MM-DD
      excludes weekends
      section A section
        Completed task : done, des1, 2014-01-06, 2014-01-08
        Active task : active, des2, 2014-01-09, 3d
        Future task : des3, after des2, 5d
        Future task2 : des4, after des3, 5d
      section Critical tasks
        Completed task in the critical line : crit, done, 2014-01-06, 24h
        Implement parser and jison : crit, done, after des1, 2d
        Create tests for parser : crit, active, 3d
        Future task in critical line : crit, 5d
        Create tests for renderer : 2d
        Add to mermaid : until isadded
        Functionality added : milestone, isadded, 2014-01-25, 0d
      section Documentation
        Describe gantt syntax : active, a1, after des1, 3d
        Add gantt diagram to demo page : after a1, 20h
        Add another diagram to demo page : doc1, after a1, 48h
      section Last section
        Describe gantt syntax : after doc1, 3d
        Add gantt diagram to demo page : 20h
        Add another diagram to demo page : 48h
    </pre>

Mermaid Diagram
+++++++++++++++

.. mermaid::

    gantt
      title Adding GANTT diagram functionality to mermaid
      dateFormat YYYY-MM-DD
      excludes weekends
      section A section
        Completed task : done, des1, 2014-01-06, 2014-01-08
        Active task : active, des2, 2014-01-09, 3d
        Future task : des3, after des2, 5d
        Future task2 : des4, after des3, 5d
      section Critical tasks
        Completed task in the critical line : crit, done, 2014-01-06, 24h
        Implement parser and jison : crit, done, after des1, 2d
        Create tests for parser : crit, active, 3d
        Future task in critical line : crit, 5d
        Create tests for renderer : 2d
        Add to mermaid : until isadded
        Functionality added : milestone, isadded, 2014-01-25, 0d
      section Documentation
        Describe gantt syntax : active, a1, after des1, 3d
        Add gantt diagram to demo page : after a1, 20h
        Add another diagram to demo page : doc1, after a1, 48h
      section Last section
        Describe gantt syntax : after doc1, 3d
        Add gantt diagram to demo page : 20h
        Add another diagram to demo page : 48h