How to use
============

Primary info about UI Healthbars
**********************************

First of all, you need to know, that there should be two objects on a scene to start using 
**Healthbars Kit**. 

First one is an empty object with **UIHealthbars** component: 

.. image:: ui-healthbars.png

Second one needed object is the **Canvas** to draw healthbars. You can use your own or use our
**HealthbarsCanvas** object from the **Example** scene. Its settings are very simple (similar to default 
Unity Canvas settings):

.. image:: ui-canvas.png

After this, you need drag your canvas to **UIHealthbars** component **Healthbars
Canvas** field.

Now all ready to adding healthbars to your units. There are two ways how it can be 
done.

Setup using ready-made component
*********************************

If your units actually have not any components, which are responsible for health, unit 
damage and unit death, you can use ready **Damageable** component from the **Healthbars Kit**. It 
has **health** and **max health** parameters and **Take Damage** method, which allows to deal 
damage to the unit. Also it has **Die** method, which responsible to unit death and actions 
which will be started on this event. You can extend this component to your needs or create 
inherited class with more parameters.

To use this **Damageable**, simple add this component to any of your units (and next you 
can make Prefab from this unit):

.. image:: damageable.png

Now you can enter play mode and you should see healthbar above this unit:

.. image:: result.png

Setup from code
******************************

This is **alternative** setup method.

If you already have component with unit health and take damage methods, you should 
add new code to it. Btw, You can find and copy all code, shown in this guide, in the **Damageable** script.

Firstly, add event to the beginning of your script:

.. code-block:: csharp
  
  public event UIHealthbars.HealthChangedAction HealthWasChanged;


.. Note::
   Don’t forget to add using reference to the **InsaneSystems.HealthbarsKit.UI**.

Next, you need to add **AddHealthbar** and **OnHealthChanged** methods:

.. code-block:: csharp

  void Start()
  {
    var healthBar = UIHealthbars.AddHealthbar(gameObject, maxHealth);
    
    // Setting up event to connect the Healthbar with this Damageable.
    // Now every time when it will take damage, Healthbar will be updated.
    HealthWasChanged += healthBar.OnHealthChanged; 
    
    OnHealthChanged();
  }

  void OnHealthChanged() => HealthWasChanged?.Invoke(health);


Finally, add call of the **OnHealthChanged** method in place, where you deal damage to 
your unit:

.. code-block:: csharp

  public void TakeDamage(float damage)
  {
    health = Mathf.Clamp(health - damage, 0, maxHealth);   

    OnHealthChanged();  

    if (health == 0)
    	Die();
  }

.. note::
  You need also add **OnHealthChanged** in healing part of your code, if you have it.

**Done!**