Code may be routed depending on a keyboard press. For example, say you want to call a method which exists elsewhere known as moveUp(), which moves your character upwards. You only want to do this if the 'w' key is pressed on the keyboard. You must check that it is a keyboard event, which you can do by checking if type of the EventType object is equal to the constant KEYDOWN, which stores the integer value for keydown type events. Then, you could check the 'key' attribute on the keyboard event's EventType object, which stores which key was pressed in the form of an integer. Thankfully, there are also built in constants for this. The constant is always 'K_' followed by the key itself. For 'w', it is 'K_w'.
```Python
for event in pygame.event.get() #this block iterates through the queue
	if event.EventType.type == pygame.KEYDOWN: #if the event has type keydown
		if event.EventType.type == pygame.K_w: #if event key attribute is equal to w 
                      moveUp() #call moveUp()!
```

Executing Code Based on Keyboard Events in Pygame

There are three types of mouse events in pygame: 1. MOUSEBUTTONUP, for when a mouse's button is released. 2. MOUSEBUTTONDOWN, for when a mouse's button is pressed. 3. MOUSEMOTION, for when the mouse moves across
the screen. Each EventType object generated has a number of attributes which are listed below.

MOUSEMOTION:
- buttons: a tuple containing the buttons on the mouse being pressed
- pos: the xy coordinates of the cursor after movement
- rel: the xy coordinates of the post-movement position relative to the previous position (AKA the distance)

MOSUEBUTTONDOWN and MOUSEBUTTONUP:
- button: an int representing the button being pressed. 1 for left button, 2 for mosue wheel, 3 for right button, 4 for scrolling up, and 5 for scrolling down.
- pos: the xy coordinates of the cursor when the button was pressed

Mouse Events in Pygame

The event queue can be accessed with the method event.get(), as demonstrated below.

```Python
eventQueue = pygame.event.get()
```

University of Michigan - Ann Arbor

Pygame registers a lot of different interactions from peripherals, such as mouse and keyboard, through events. It also registers certain actions, such as attempting to
close the program, as an event. Events are objects which store a type (an int), describing what type of event it is, and potential additional attributes. Pygame stores the events in a queue--henceforth this will be referred to as the event queue. You can receive the queue yourself using a get method, and then decide what to do based on what the event was. For example, if the user pressed an arrow key on the keyboard, you could execute some method to move their character on the screen. Note that you can also do this by directly accessing the keyboard and mouse modules themselves, ignoring the event queue entirely.

Events in Pygame

Pygame Documentation

Accessing the Event Queue in Pygame

Pygame also has objects to store the type and attributes of a given event. The type is an integer that is stored inside a constant. These are EventType objects, and are themselves attributes of the Event object. Events of a certain type are guaranteed to have CERTAIN attributes. Here is a list of all event types and the attributes they each have:

```Python
TYPE                     ATTRIBUTE
QUIT                     none
ACTIVEEVENT       gain, state
KEYDOWN           key, mod, unicode, scancode
KEYUP                  key, mod
MOUSEMOTION       pos, rel, buttons
MOUSEBUTTONUP     pos, button
MOUSEBUTTONDOWN   pos, button
JOYAXISMOTION     joy (deprecated), instance_id, axis, value
JOYBALLMOTION     joy (deprecated), instance_id, ball, rel
JOYHATMOTION      joy (deprecated), instance_id, hat, value
JOYBUTTONUP       joy (deprecated), instance_id, button
JOYBUTTONDOWN     joy (deprecated), instance_id, button
VIDEORESIZE       size, w, h
VIDEOEXPOSE       none
USEREVENT         code
```

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