Detailed explanation of event processing and input management in PYSDL2 library

PYSDL2 is a SDL2 binding library for Python, which provides a simplified access to the SDL2 function.SDL2 is the abbreviation of Simple DirectMedia Layer. It is a cross -platform multimedia development library for processing window creation, graphic rendering, audio playback, and user input. This article will introduce the event processing and input management in the PYSDL2 library.Event processing refers to the process of responding to the user input or other system events during runtime.It is the key part of the development of interactive applications, such as games, graphic user interfaces.Entering management refers to the process of processing and managing user input (such as keyboards, mouse events). In order to use the PYSDL2 library, SDL2 is first installed on the system.You can download and install the installation program through the package manager or from the official website of SDL2.After the installation is completed, we can use the PIP command to install the PYSDL2 library. pip install PySDL2 Next, let's write a simple PYSDL2 program in order to deeply understand the principles of incident processing and input management. python import sdl2.ext def run(): sdl2.ext.init() window = sdl2.ext.Window("PySDL2 Demo", size=(800, 600)) window.show() running = True while running: for event in sdl2.ext.get_events(): if event.type == sdl2.SDL_QUIT: running = False sdl2.ext.quit() if __name__ == "__main__": run() In this sample program, we first introduced the SDL2.Ext module, which contains the expansion function of the PYSDL2 library.Then we use the sdl2.ext.init () function to initialize the PYSDL2 library.Next, we created a window object and displayed it. Then, we entered a main loop, where we use sdl2.ext.get_events () function to obtain all the current events.We can respond to various events types by iterating.In this example, we checked whether the SDL_quit type event occurred, that is, the user clicked the closing button of the window.If this incident occurs, we set the running status of the program to false, so as to jump out of the main loop and exit the program. Finally, we use the SDL2.Ext.quit () function to turn off the PYSDL2 library and perform cleanup. In addition to monitoring the incident, we can also monitor and handle other types of events, such as keyboard events and mouse events.In the PYSDL2 library, the type of event is expressed as the Type field of the SDL_Event structure.By checking the value of the Type field, we can determine the type of the event.For example, the types of keyboard events are SDL_KEYDOWN and SDL_KEYUP, and the types of mouse events are SDL_MOUSEMOTION, SDL_MOUSEBUTTONDOWN and SDL_MOUSEBUTTONUP. In addition, the PYSDL2 library also provides some other functions, such as obtaining keyboard status, mouse position, etc.By calling related functions, we can get information of the current keyboard keys, as well as coordinates of the mouse position, so as to better manage the user input. To sum up, the PYSDL2 library provides a simplified interface to process events and manages user input.By monitoring and responding to different types of events, we can write interactive applications and games.At the same time, the PYSDL2 library also provides other functions to easily obtain user input information and conduct relevant processing and management.