Pygame按钮集成及界面切换的实现

pygame是python轻量级的游戏框架，通常用于微型小游戏的创作或者游戏编程思想的教育。pygame的功能集成程度比较低，通常需要将功能代码人工再次集成包装（模块化、类化）才能更好地减少代码量，起到复用的效果。

下面展示一段按钮集成的代码。展示了纯文本（Text)， 图片（Image)，纯色（ColorSurface），以及这三种对应的按钮（即附加事件触发功能）的类设计。

from calendar import c
import os
import random
import sys

import pygame
from pygame import font
from pygame.constants import MOUSEBUTTONDOWN, MOUSEMOTION


class Color:
    # 自定义颜色
    ACHIEVEMENT = (220, 160, 87)
    VERSION = (220, 160, 87)

    # 固定颜色
    BLACK = (0, 0, 0)
    WHITE = (255, 255, 255)
    RED = (255, 0, 0)
    GREEN = (0, 255, 0)
    BLUE = (0, 0, 255)
    GREY = (128, 128, 128)  # 中性灰
    TRANSPARENT = (255, 255, 255, 0)  # 白色的完全透明


class Text:
    def __init__(self, text: str, text_color: Color, font_type: str, font_size: int):
        """
        text: 文本内容，如'大学生模拟器'，注意是字符串形式
        text_color: 字体颜色，如Color.WHITE、COLOR.BLACK
        font_type: 字体文件(.ttc)，如'msyh.ttc'，注意是字符串形式
        font_size: 字体大小，如20、10
        """
        self.text = text
        self.text_color = text_color
        self.font_type = font_type
        self.font_size = font_size

        font = pygame.font.Font(os.path.join('font', (self.font_type)), self.font_size)
        self.text_image = font.render(self.text, True, self.text_color).convert_alpha()

        self.text_width = self.text_image.get_width()
        self.text_height = self.text_image.get_height()

    def draw(self, surface: pygame.Surface, center_x, center_y):
        """
        surface: 文本放置的表面
        center_x, center_y: 文本放置在表面的<中心坐标>
        """
        upperleft_x = center_x - self.text_width / 2
        upperleft_y = center_y - self.text_height / 2
        surface.blit(self.text_image, (upperleft_x, upperleft_y))


class Image:
    def __init__(self, img_name: str, ratio=0.4):
        """
        img_name: 图片文件名，如'background.jpg'、'ink.png',注意为字符串
        ratio: 图片缩放比例，与主屏幕相适应，默认值为0.4
        """
        self.img_name = img_name
        self.ratio = ratio

        self.image_1080x1920 = pygame.image.load(os.path.join('image', self.img_name)).convert_alpha()
        self.img_width = self.image_1080x1920.get_width()
        self.img_height = self.image_1080x1920.get_height()

        self.size_scaled = self.img_width * self.ratio, self.img_height * self.ratio

        self.image_scaled = pygame.transform.smoothscale(self.image_1080x1920, self.size_scaled)
        self.img_width_scaled = self.image_scaled.get_width()
        self.img_height_scaled = self.image_scaled.get_height()

    def draw(self, surface: pygame.Surface, center_x, center_y):
        """
        surface: 图片放置的表面
        center_x, center_y: 图片放置在表面的<中心坐标>
        """
        upperleft_x = center_x - self.img_width_scaled / 2
        upperleft_y = center_y - self.img_height_scaled / 2
        surface.blit(self.image_scaled, (upperleft_x, upperleft_y))


class ColorSurface:
    def __init__(self, color, width, height):
        self.color = color
        self.width = width
        self.height = height

        self.color_image = pygame.Surface((self.width, self.height)).convert_alpha()
        self.color_image.fill(self.color)

    def draw(self, surface: pygame.Surface, center_x, center_y):
        upperleft_x = center_x - self.width / 2
        upperleft_y = center_y - self.height / 2
        surface.blit(self.color_image, (upperleft_x, upperleft_y))


class ButtonText(Text):
    def __init__(self, text: str, text_color: Color, font_type: str, font_size: int):
        super().__init__(text, text_color, font_type, font_size)
        self.rect = self.text_image.get_rect()

    def draw(self, surface: pygame.Surface, center_x, center_y):
        super().draw(surface, center_x, center_y)
        self.rect.center = center_x, center_y

    def handle_event(self, command):
        self.hovered = self.rect.collidepoint(pygame.mouse.get_pos())
        if self.hovered:
            command()


class ButtonImage(Image):
    def __init__(self, img_name: str, ratio=0.4):
        super().__init__(img_name, ratio)
        self.rect = self.image_scaled.get_rect()

    def draw(self, surface: pygame.Surface, center_x, center_y):
        super().draw(surface, center_x, center_y)
        self.rect.center = center_x, center_y

    def handle_event(self, command):
        self.hovered = self.rect.collidepoint(pygame.mouse.get_pos())
        if self.hovered:
            command()


class ButtonColorSurface(ColorSurface):
    def __init__(self, color, width, height):
        super().__init__(color, width, height)
        self.rect = self.color_image.get_rect()

    def draw(self, surface: pygame.Surface, center_x, center_y):
        super().draw(surface, center_x, center_y)
        self.rect.center = center_x, center_y

    def handle_event(self, command, *args):
        self.hovered = self.rect.collidepoint(pygame.mouse.get_pos())
        if self.hovered:
            command(*args)

pygame通过死循环持续监听事件发生，而游戏内容则是通过界面刷新来完成。因此，需要游戏界面切换时，也需要在死循环中设置事件为界面刷新。

为了清晰地描述代码作用，以下仅展示最小功能，完整的pygame按钮集成及界面切换的实现可移步文末的github链接。注意下面代码也使用了上文定义的按钮类。

class InterFace():
    def __init__(self):
        pygame.init()

    def basic_background(self):
        """
        <基本背景>\n
        返回值为背景尺寸和背景表面
        """
        # 设置logo和界面标题
        game_icon = pygame.image.load(os.path.join('image', 'college_icon.png'))
        game_caption = '大学生模拟器'
        pygame.display.set_icon(game_icon)
        pygame.display.set_caption(game_caption)

        # 设置开始界面
        show_ratio = 0.4
        size = width, height = 1080 * show_ratio, 1920 * show_ratio
        screen = pygame.display.set_mode(size)

        # 设置背景贴图
        Image('background.jpg').draw(screen, width / 2, height / 2)

        return size, screen

    def start_interface(self):
        """
        <开始界面>
        """
        # 设置<基本背景>
        size, screen = self.basic_background()
        width, height = size

        # 设置<开始界面>文字和贴图
        Image('ink.png', ratio=0.4).draw(screen, width * 0.52, height * 0.67)  # 墨印
        Image('achievement_icon.png', ratio=0.25).draw(screen, width * 0.93, height * 0.05)  # 成就按钮

        Text('大学生模拟器', Color.BLACK, 'HYHanHeiW.ttf', 50).draw(screen, width / 2, height * 1 / 3)  # 游戏名
        Text('Alpha 0.0', Color.VERSION, 'msyh.ttc', 12).draw(screen, width / 2, height * 0.97)  # 版本号
        Text('成就', Color.ACHIEVEMENT, 'msyh.ttc', 16).draw(screen, width * 0.93, height * 0.09)  # 成就

        button_game_start = ButtonText('开始游戏', Color.WHITE, 'msyh.ttc', 23)  # 开始游戏按钮
        button_game_start.draw(screen, width / 2, height * 2 / 3)

        while True:
            for event in pygame.event.get():
                if event.type == pygame.QUIT:
                    pygame.quit()
                    sys.exit()
                
                # ！此处为界面切换的关键，即进入另一死循环
                if event.type == pygame.MOUSEBUTTONDOWN:
                    button_game_start.handle_event(self.initial_attribute_interface)

            pygame.display.update()

    def initial_attribute_interface(self):
        """
        <初始属性界面>
        """
        # 设置基本背景
        size, screen = self.basic_background()
        width, height = size
        
        # 放置各种按钮
        Image('返回.png', ratio=0.38).draw(screen, width * 0.07, height * 0.047)
        button_back = ButtonColorSurface(Color.TRANSPARENT, 26, 26)
        button_back.draw(screen, width * 0.07, height * 0.047)

        while True:
            for event in pygame.event.get():
                if event.type == pygame.QUIT:
                    pygame.quit()
                    sys.exit()

                # ！此处为界面切换的关键，即进入另一死循环
                if event.type == pygame.MOUSEBUTTONDOWN:
                    button_back.handle_event(self.start_interface)

            pygame.display.update()


if __name__ == '__main__':
    scene = InterFace()
    # 开始时选定start_interface
    scene.start_interface()

完整可运行代码文件夹：

https://github.com/AkinaZed/pygame-button-interface-switch