How to use Pygame's Event event module in Python

Pygame's Event module

Event (Event) is one of the important modules of Pygame. It is the core of building the entire game program, such as commonly used mouse clicks, keyboard taps, game window movements, and adjustments. Window size, triggering specific plots, exiting the game, etc., can all be regarded as "events".

Event Type

Pygame defines a structure specifically used to process events, namely the event queue. This structure follows the basic principle of "first come, first processed" of the queue. Through the event queue, we User operations (triggered events) can be processed in an orderly and one-by-one manner. The following table lists commonly used game events in Pygame:

Gameball(Joy ball) Move##JOYHATMOTIONJOYBUTTONDOWN##JOYBUTTONUPVIDEORESIZEVIDEOEXPOSE##USEREVENT Note that when using Pygame for game development, not all the above events will be applied. Therefore, in the process of learning, we must know how to draw inferences and draw inferences.

Name	Description
QUIT	The user presses the close button of the window
ATIVEEVENT	Pygame Activate or hide
KEYDOWN	Keyboard press
KEYUP	Keyboard release
MOUSEMOTION	Mouse movement
MOUSEBUTTONDOWN	Mouse pressed
MOUSEBUTTONUP	Mouse released
JOYAXISMOTION	Game handle (Joystick or pad) movement
##JOYBALLMOTION
Game Controller(Joystick) Move
Game handle pressed
Game handle released
Pygame window scaling
Pygame window partially exposed (expose)
Trigger a user event

Event handling method

NameDescriptionpygame.event.get()pygame.event.wait() pygame.event.set_blocked() pygame.event.set_allowed() pygame.event.pump() pygame.event.poll() Detect whether a certain type of event is in the queueClear all events from the queueDetect whether a certain type of event is prohibited from entering the queuePlace a new event into the queueCreate one New user-defined events

When we use Pygame to handle events, the logic is generally similar. You need to determine the type of event first, and then take different game actions for each event type. Therefore, if & else statements are ideal for this situation. As shown below:

import pygame

while True:
    # 等待事件发生
    event = pygame.event.wait()
    if event.type == pygame.QUIT:
        exit()
    if event.type == pygame.MOUSEBUTTONDOWN:
        print('鼠标按下', event.pos)
    if event.type == pygame.MOUSEBUTTONUP:
        print('鼠标弹起')
    if event.type == pygame.MOUSEMOTION:
        print('鼠标移动')
        # 键盘事件
    if event.type == pygame.KEYDOWN:
        # 打印按键的英文字符
        print('键盘按下', chr(event.key))
    if event.type == pygame.KEYUP:
        print('键盘弹起')

Handling keyboard events

We can use the key attribute provided by the keyboard event to get the pressed keyboard key. Pygame defines the letter keys, numeric keys, combination keys and other keys on the keyboard in the form of constants. The following table lists the constants of some commonly used keys:

Get an event from the event queue and delete the event from the queue
Blocking will not continue until the event occurs. If no event occurs, it will remain blocked
Control which events are prohibited from entering the queue. If the parameter value is None, it means that all events are prohibited from entering
Control which events are allowed to enter the queue
After calling this method, Pygame will automatically process the event queue
will be processed according to the actual situation Returns a real event, or None	##pygame.event.peek()
	pygame.event.clear()
	pygame.event.get_blocked()
	pygame.event.post()
	pygame.event.Event()

a…zDelete key (delete)##K_KP0...K_KP9K_F1...K_F15K_UPK_DOWNK_RIGHTK_LEFTKMOD_ALT Let’s use the “picture movement” example to understand the keyboard event processing process, as shown below:

Name	Instructions
K_BACKSPACE	Backspace
K_TAB	Tab
K_CLEAR	Clear key (Clear)
K_RETURN	Enter key (Enter)
K_PAUSE	Pause button
K_ESCAPE	Escape button
K_SPACE	Space bar (Space)
K_0...K_9	0…9
#K_a...Kz
K_DELETE
0 (small keyboard)...9 (small keyboard)
F1…F15
Up arrow
Towards Down arrow
right arrow
Left arrow
Press the Alt key at the same time

import pygame
import sys

# 初始化pygame
pygame.init()
# 定义变量
size = width, height = 600, 400
bg = (255, 255, 255)
# 加载logo图
img = pygame.image.load("./python.png")
# 获取图像的位置
position = img.get_rect()
# 创建一个主窗口
screen = pygame.display.set_mode(size)
# 标题
pygame.display.set_caption("Python自学网")
# 创建游戏主循环
while True:
    # 设置初始值
    site = [0, 0]
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            sys.exit()
        # 图像移动 KEYDOWN 键盘按下事件
        # 通过 key 属性对应按键
        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_UP:
                site[1] -= 8
            if event.key == pygame.K_DOWN:
                site[1] += 8
            if event.key == pygame.K_LEFT:
                site[0] -= 8
            if event.key == pygame.K_RIGHT:
                site[0] += 8
    # 移动图像
    position = position.move(site)
    # 填充背景
    screen.fill(bg)
    # 放置图片
    screen.blit(img, position)
    # 更新显示界面
    pygame.display.flip()

Handling mouse events

Pygame provides three mouse events, namely mouse movement (MOUSEMOTION), mouse press (MOUSEBUTTONDOWN), and mouse release (MOUSEBUTTONUP). Different event types correspond to different member attributes. As shown below:

pygame.event.MOUSEMOTION mouse movement event

event.pos relative to the upper left corner of the window, the current coordinate value of the mouse (x, y)

event.rel mouse Relative movement distance (X, Y), relative to the last event

event.buttons The initial state of the mouse button (0,0,0), corresponding to (left button, pulley, right button) respectively, which button is clicked during the movement, The corresponding position will change to 1

pygame.event.MOUSEBUTTONUP mouse button release event

event.pos relative to the upper left corner of the window, the current coordinate value of the mouse (x, y)

event .button Mouse release key number (integer) The left button is 1, the scroll wheel is pressed 2, the right button is 3

pygame.event.MOUSEBUTTONDOWN Mouse button press event

event.pos relative to The upper left corner of the window, the current coordinate value of the mouse (x, y)

event.button mouse button number (integer), the left button is 1, press the scroll wheel 2, the right button is 3, scroll the wheel 4 forward, Roll the pulley backward 5

import pygame
from random import randint

# 初始化程序
pygame.init()
screen = pygame.display.set_mode((450, 400))
pygame.display.set_caption("Python自学网")
# 更新显示
pygame.display.flip()
while True:
    # 等待事件发生
    event = pygame.event.wait()
    if event.type == pygame.QUIT:
        exit("成功退出")
    if event.type == pygame.MOUSEBUTTONDOWN:
        # pos 获取鼠标当前位置
        print('鼠标按下', event.pos)
        mx, my = event.pos
        # 调用 pygame.draw 模块画圆
        pygame.draw.circle(screen, (255, 255, 0), (mx, my), 50)
        # 处理完，更新显示
        pygame.display.update()
    if event.type == pygame.MOUSEBUTTONUP:
        print('鼠标弹起')
        pass
    if event.type == pygame.MOUSEMOTION:
        print('鼠标移动')
        mx, my = event.pos
        # 随机生成 RGB 颜色值
        r = randint(0, 255)
        g = randint(0, 255)
        b = randint(0, 255)
        pygame.draw.circle(screen, (r, g, b,), (mx, my), 50)
        # 处理完，更新显示
        pygame.display.update()

The above is the detailed content of How to use Pygame's Event event module in Python. For more information, please follow other related articles on the PHP Chinese website!