pygame.mouse
  
 pygame module to work with the mouse  The mouse functions can be used to get the current state of the mouse device. These functions can also alter the system cursor for the mouse. When the display mode is set, the event queue will start receiving mouse events. The mouse buttons generate pygame.MOUSEBUTTONDOWN and pygame.MOUSEBUTTONUP events when they are pressed and released. These events contain a button attribute representing which button was pressed. The mouse wheel will generate pygame.MOUSEBUTTONDOWN and pygame.MOUSEBUTTONUP events when rolled. The button will be set to 4 when the wheel is rolled up, and to button 5 when the wheel is rolled down. Whenever the mouse is moved it generates a pygame.MOUSEMOTION event. The mouse movement is broken into small and accurate motion events. As the mouse is moving many motion events will be placed on the queue. Mouse motion events that are not properly cleaned from the event queue are the primary reason the event queue fills up. If the mouse cursor is hidden, and input is grabbed to the current display the mouse will enter a virtual input mode, where the relative movements of the mouse will never be stopped by the borders of the screen. See the functions pygame.mouse.set_visible() and pygame.event.set_grab() to get this configured. Mouse Wheel Behavior in pygame 2 There is proper functionality for mouse wheel behaviour with pygame 2 supporting pygame.MOUSEWHEEL events. The new events support horizontal and vertical scroll movements, with signed integer values representing the amount scrolled (x and y), as well as flipped direction (the set positive and negative values for each axis is flipped). Read more about SDL2 input-related changes here https://wiki.libsdl.org/MigrationGuide#Input In pygame 2, the mouse wheel functionality can be used by listening for the pygame.MOUSEWHEEL type of an event. When this event is triggered, a developer can access the appropriate Event object with pygame.event.get(). The object can be used to access data about the mouse scroll, such as which (it will tell you what exact mouse device trigger the event).  Code example of mouse scroll (tested on 2.0.0.dev7) 
# Taken from husano896's PR thread (slightly modified)
import pygame
from pygame.locals import *
pygame.init()
screen = pygame.display.set_mode((640, 480))
clock = pygame.time.Clock()

def main():
   while True:
      for event in pygame.event.get():
            if event.type == QUIT:
               pygame.quit()
               return
            elif event.type == MOUSEWHEEL:
               print(event)
               print(event.x, event.y)
               print(event.flipped)
               print(event.which)
               # can access properties with
               # proper notation(ex: event.y)
      clock.tick(60)

# Execute game:
main()
     pygame.mouse.get_pressed() 
 get the state of the mouse buttons get_pressed(num_buttons=3) -> (button1, button2, button3) get_pressed(num_buttons=5) -> (button1, button2, button3, button4, button5)  Returns a sequence of booleans representing the state of all the mouse buttons. A true value means the mouse is currently being pressed at the time of the call. Note, to get all of the mouse events it is better to use either pygame.event.wait() or pygame.event.get() and check all of those events to see if they are MOUSEBUTTONDOWN, MOUSEBUTTONUP, or MOUSEMOTION. Note, that on X11 some X servers use middle button emulation. When you click both buttons 1 and 3 at the same time a 2 button event can be emitted. Note, remember to call pygame.event.get() before this function. Otherwise it will not work as expected. To support five button mice, an optional parameter num_buttons has been added in pygame 2. When this is set to 5, button4 and button5 are added to the returned tuple. Only 3 and 5 are valid values for this parameter.  Changed in pygame 2.0.0: num_buttons argument added  
   pygame.mouse.get_pos() 
 get the mouse cursor position get_pos() -> (x, y)  Returns the x and y position of the mouse cursor. The position is relative to the top-left corner of the display. The cursor position can be located outside of the display window, but is always constrained to the screen. 
   pygame.mouse.get_rel() 
 get the amount of mouse movement get_rel() -> (x, y)  Returns the amount of movement in x and y since the previous call to this function. The relative movement of the mouse cursor is constrained to the edges of the screen, but see the virtual input mouse mode for a way around this. Virtual input mode is described at the top of the page. 
   pygame.mouse.set_pos() 
 set the mouse cursor position set_pos([x, y]) -> None  Set the current mouse position to arguments given. If the mouse cursor is visible it will jump to the new coordinates. Moving the mouse will generate a new pygame.MOUSEMOTION event. 
   pygame.mouse.set_visible() 
 hide or show the mouse cursor set_visible(bool) -> bool  If the bool argument is true, the mouse cursor will be visible. This will return the previous visible state of the cursor. 
   pygame.mouse.get_visible() 
 get the current visibility state of the mouse cursor get_visible() -> bool  Get the current visibility state of the mouse cursor. True if the mouse is visible, False otherwise.  New in pygame 2.0.0.  
   pygame.mouse.get_focused() 
 check if the display is receiving mouse input get_focused() -> bool  Returns true when pygame is receiving mouse input events (or, in windowing terminology, is "active" or has the "focus"). This method is most useful when working in a window. By contrast, in full-screen mode, this method always returns true. Note: under MS Windows, the window that has the mouse focus also has the keyboard focus. But under X-Windows, one window can receive mouse events and another receive keyboard events. pygame.mouse.get_focused() indicates whether the pygame window receives mouse events. 
   pygame.mouse.set_cursor() 
 set the image for the mouse cursor set_cursor(size, hotspot, xormasks, andmasks) -> None  When the mouse cursor is visible, it will be displayed as a black and white bitmap using the given bitmask arrays. The size is a sequence containing the cursor width and height. hotspot is a sequence containing the cursor hotspot position. A cursor has a width and height, but a mouse position is represented by a set of point coordinates. So the value passed into the cursor hotspot variable helps pygame to actually determine at what exact point the cursor is at. xormasks is a sequence of bytes containing the cursor xor data masks. Lastly andmasks, a sequence of bytes containing the cursor bitmask data. To create these variables, we can make use of the pygame.cursors.compile() function. Width and height must be a multiple of 8, and the mask arrays must be the correct size for the given width and height. Otherwise an exception is raised. See the pygame.cursor module for help creating default and custom masks for the mouse cursor and also for more examples related to cursors. 
   pygame.mouse.set_system_cursor() 
 set the mouse cursor to a system variant set_system_cursor(constant) -> None  When the mouse cursor is visible, it will displayed as a operating system specific variant of the options below. Pygame Cursor Constant           Description
--------------------------------------------
pygame.SYSTEM_CURSOR_ARROW       arrow
pygame.SYSTEM_CURSOR_IBEAM       i-beam
pygame.SYSTEM_CURSOR_WAIT        wait
pygame.SYSTEM_CURSOR_CROSSHAIR   crosshair
pygame.SYSTEM_CURSOR_WAITARROW   small wait cursor
                                 (or wait if not available)
pygame.SYSTEM_CURSOR_SIZENWSE    double arrow pointing
                                 northwest and southeast
pygame.SYSTEM_CURSOR_SIZENESW    double arrow pointing
                                 northeast and southwest
pygame.SYSTEM_CURSOR_SIZEWE      double arrow pointing
                                 west and east
pygame.SYSTEM_CURSOR_SIZENS      double arrow pointing
                                 north and south
pygame.SYSTEM_CURSOR_SIZEALL     four pointed arrow pointing
                                 north, south, east, and west
pygame.SYSTEM_CURSOR_NO          slashed circle or crossbones
pygame.SYSTEM_CURSOR_HAND        hand  New in pygame 2.0.0.  
   pygame.mouse.get_cursor() 
 get the image of the mouse cursor get_cursor() -> (size, hotspot, xormasks, andmasks)  Get the information about the mouse system cursor. The return value is the same data as the arguments passed into pygame.mouse.set_cursor().  Note This method is unavailable with pygame 2, as SDL2 does not provide the underlying code to implement this method.