How To Display Moving Text In Pygame

The pygame.font module provides methods for you to display text on the Pygame window screen. This article will tell you how to draw text on a Pygame surface object with examples.

1. How To Draw Text On Pygame Screen Steps.

  1. You can call the pygame.font.SysFont(name, size, bold=False, italic=False) -> Font method to create a pygame.font.Font object from the system-supported font.
  2. The name is a string that represents the font name, the size is an integer that represents the font size.
    font_object = pygame.font.SysFont('classinfont', 32, bold = True, italic = True)
  3. If you have a text font file for example abc.ttf, then you can use the method pygame.font.Font(font_file_path, 32) to create a pygame.font.Font object.
    font_object = pygame.font.Font('/usr/local/abc.ttf', 32)
  4. Then you can call the pygame.font.Font object’s render(text, antialias, color, background=None) -> Surface method to create a text surface object.
    TEXT_SURFACE_OBJECT = font_object.render('Hello pygame world!', True, text_color, text_background_color)
  5. To specify the text surface object drawn location, you should first get the pygame.Rect object of the text surface object.
    text_rect_object = TEXT_SURFACE_OBJECT.get_rect()
  6. Then you can specify the text surface object’s position by specifying the pygame.Rect object’s center attribute value.
    text_rect_object.center = (TEXT_CENTER_X, TEXT_CENTER_Y)
  7. Now you can draw the text surface object to the pygame main window surface object with the provided pygame.Rect object as the text surface object’s position.
    MAIN_WINDOW_SURFACE.blit(TEXT_SURFACE_OBJECT, text_rect_object)

2. Draw Text On Pygame Window Examples.

  1. In this example, it will draw a text on the main window’s screen center, and then the text will move horizontally.
  2. When the text touches the main window screen’s edge, it will turn back and move in the opposite direction.
  3. The python source file name is PygameDrawText.py, below is the file content.
    '''
    Created on Feb 14, 2022
    
    @author: songzhao
    '''
    
    import pygame, random, sys
    
    # define the pygame main window surface object.
    MAIN_WINDOW_SURFACE = None
    
    # define the pygame.time.Clock object to control the frames refresh frequency.
    FRAME_PER_SECOND_CLOCK = None
    
    # define the frame per second numbers, that means one second draw 23 frame at most.
    FPS = 23
    
    # define the text surface object.
    TEXT_SURFACE_OBJECT = None
    
    # define the direction constants.
    LEFT = 'LEFT'
    RIGHT = 'RIGHT'
    DIRECTION = LEFT
    
    # the text move steps.
    MOVE_STEP = 5
    
    # define the text surface rectangle's center (x, y) coordinates.
    TEXT_CENTER_X = 0
    TEXT_CENTER_Y = 0
    
    
    # this function initialize the pygame application.
    def initialize_pygame():
        
        pygame.init()
        
        # create the game main window.
        main_window_size = (1000, 300)
        
        global MAIN_WINDOW_SURFACE
        MAIN_WINDOW_SURFACE = pygame.display.set_mode(main_window_size, pygame.RESIZABLE)
        
        # set the window title.
        window_title = 'Pygame Draw Moving Text With Specified Text Font Example.'
        pygame.display.set_caption(window_title)
            
        # create a pygame.time.Clock object.
        global FRAME_PER_SECOND_CLOCK
        FRAME_PER_SECOND_CLOCK = pygame.time.Clock()
        
      
    # get a text font from the system supported font list.    
    def get_random_text_font():
        
        # get all system supported fonts.
        system_fonts_list = pygame.font.get_fonts()
        
        system_fonts_list = ['signpainter', 'shree714', 'songti']
        # get a random text font from the above fonts list.
        ret_text_font = random.choice(system_fonts_list)
        
        return ret_text_font    
    
    
    # initialize the moving text surface object.    
    def initialize_moving_text():
            
        # get a random text font.    
        text_font = get_random_text_font()
        print('text_font = ', text_font)
        
        # create a pygame.font.Font object use the pygame.font.SysFont() method.
        font_object = pygame.font.SysFont(text_font, 32, bold = True, italic = True)
        
        # define the text color and text background color.
        text_color = pygame.Color('green')
        text_background_color = pygame.Color('blue')
    
        global TEXT_SURFACE_OBJECT
        # call the pygame.font.Font's object's render() method to create the text surface object.
        TEXT_SURFACE_OBJECT = font_object.render('Hello pygame world!', True, text_color, text_background_color) 
        
        # get the pygame main screen window's width and height.
        window_width = MAIN_WINDOW_SURFACE.get_width()
        window_height = MAIN_WINDOW_SURFACE.get_height()
        
        # calculate the text surface object's rectangle object's center coordinates.
        global TEXT_CENTER_X
        global TEXT_CENTER_Y
        
        # when the pygame starts, the text surface object is located at the main window screen center.
        if TEXT_CENTER_X ==0:
            
            TEXT_CENTER_X = window_width/2
            TEXT_CENTER_Y = window_height/2
        
        # get the text surface object's pygame.Rect object.
        text_rect_object = TEXT_SURFACE_OBJECT.get_rect()
        # position the text rectangle object' center to coordinate(TEXT_CENTER_X, TEXT_CENTER_Y).
        text_rect_object.center = (TEXT_CENTER_X, TEXT_CENTER_Y)    
        
        # clear the main window screen by drawing white color.
        MAIN_WINDOW_SURFACE.fill(pygame.Color('white'))
        # draw the text surface object to the pygame main window.    
        MAIN_WINDOW_SURFACE.blit(TEXT_SURFACE_OBJECT, text_rect_object)
    
    # this function will move the text on the screen by changing the text surface object center point coordinates. 
    def draw_moving_text():
        
        global DIRECTION, TEXT_CENTER_X
        # if move to left.
        if DIRECTION == LEFT:
            # text center point's x coordinate will decrease.
            TEXT_CENTER_X -= MOVE_STEP
        # if move to right.    
        elif DIRECTION == RIGHT:
            # text center point's x coordinate will increase.
            TEXT_CENTER_X += MOVE_STEP
        
        # get the main window's width.
        window_width = MAIN_WINDOW_SURFACE.get_width()
        
        # if reach the left border.
        if TEXT_CENTER_X <=0: # change move direction to right. DIRECTION = RIGHT # if touch the right border. elif TEXT_CENTER_X >= window_width:
            # change move direction to left.
            DIRECTION = LEFT
            
        # if the text move to the main window screen center.
        if TEXT_CENTER_X == window_width/2:
            # change the text font.  
            initialize_moving_text()
        else:
            # get the text surface object's rectangle object.    
            text_rect_object = TEXT_SURFACE_OBJECT.get_rect()
            # position the text surface object to coordinates (TEXT_CENTER_X, TEXT_CENTER_Y).
            text_rect_object.center = (TEXT_CENTER_X, TEXT_CENTER_Y)    
            # clear the window by fill the white background color.
            MAIN_WINDOW_SURFACE.fill(pygame.Color('white'))
            # draw the text surface object to the main window screen with the pygame.Rect position.
            MAIN_WINDOW_SURFACE.blit(TEXT_SURFACE_OBJECT, text_rect_object)
        
    
    def main_loop():
        
         while True:
            
            draw_moving_text()
            
            # Loop to get events and listen for event status.
            for event in pygame.event.get():
                
                # if user click the window close button.
                if event.type == pygame.QUIT: 
                                   
                    # quit pygame.
                    pygame.quit()
                    
                    # quit the application.
                    sys.exit()
                
                elif event.type == pygame.KEYDOWN:
                    
                    if event.key == pygame.K_ESCAPE:
                        
                        print('The Esc key is pressed.')
                        
                        # quit pygame.
                        pygame.quit()
                    
                        # quit the application.
                        sys.exit()
                        
                elif event.type == pygame.VIDEORESIZE:
                    
                    # draw the pixel units again when user resize the pygame window. 
                    draw_moving_text()
                           
        
            pygame.display.update()
            
            # set the frame count that will be printed in one seconds. 
            FRAME_PER_SECOND_CLOCK.tick(FPS)
    
    if __name__ == '__main__':
        
        initialize_pygame()
        
        initialize_moving_text()
        
        main_loop()
        
    

3. The Pygame Draw Moving Text Example Demo Video.

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