Pygame Transform, Rotate, And Scale Image Example

This article will tell you how to transform, rotate, scale, and rotate-zoom an image in Pygame with examples.

1. How To Scale A Surface Object ( an image) In Pygame.

1. The function pygame.transform.scale(surface, size, dest_surface=None) can scale a surface object ( for example an image ) to a provided size and return the new size surface object.
2. Below is the pygame’s scale() function example source code.

   scaled_image = pygame.transform.scale(src_img_surface,(300,300))

2. How To Rotate A Surface Object ( an image ) In Pygame.

1. The function pygame.transform.rotate(surface, angle) can rotate the surface object with the provided angle, it will return a new surface object that has a rotate angle.
2. Below is the pygame’s rotate() function example source code.

   rotated_image = pygame.transform.rotate(src_img_surface, 36)

3. How To Rotate & Scale A Surface Object ( an image ) At The Same Time In Pygame.

1. The function pygame.transform.rotozoom(surface, angle, scale) can implement both rotate and scale operation to the provided surface object ( an image object ), it will return the rotated & zoomed surface object.
2. Below is the pygame’s rotozoom() function example source code.

   zommed_img = pygame.transform.rotozoom(src_img_surface, -72, 0.3)

4. How To Rotate, Scale Image In Pygame Example.

1. This example shows how to scale, rotate, zoom & rotate the surface object ( an image object ) in pygame application.
2. Below is the example source code, you can read the comments for a detailed explanation. The python source file name is PygameTransfromScaleRotateImage.py.

   '''
   Created on Feb 6, 2022
   
   @author: songzhao
   '''
   
   import pygame
   
   # define a global variable to store the pygame app main window surface.
   main_window_screen = None
   
   
   # this function will initialize the pygame main window.
   def initialize_pygame():
       
       # initialize pygame app.
       pygame.init()
       
       # set pygame window title.
       window_title = 'Pygame transform, scale, rotate image examples.'
       pygame.display.set_caption(window_title)
       
       # declare that the main_window_screen is a global variable.
       global main_window_screen 
       # create the pygame main window surface object with provided size, the window is resizable.
       main_window_screen = pygame.display.set_mode((1000,800), pygame.RESIZABLE)
       # fill the pygame main window background color to green.
       main_window_screen.fill(pygame.Color('green'))
       
       
   # this function will load an image to the pygame app main window.    
   def load_image():
       
       image_file_path = '../../../../img/dog.png'
       
       # load an image object from the image file path.
       image_surface_object = pygame.image.load(image_file_path)
       
       # call the convert_alpha() function to make the image background alpha transparency.
       image_surface_object = image_surface_object.convert_alpha()
       
       # draw the image surface object to the main window screen.
       update_screen(main_window_screen, image_surface_object, 0, 0)
       
       return image_surface_object
           
   
   # this function will scale the image surface object.
   def scale_image(src_img_surface):
       
       # scale the source image surface object to a new size.
       scaled_image = pygame.transform.scale(src_img_surface,(300,300))
   
       # draw the scaled image surface object to the pygame app main window screen.    
       update_screen(main_window_screen, scaled_image, src_img_surface.get_width()+10, 0)
       
       return scaled_image
   
   
   # this function will rotate the image surface object.
   def rotate_image(src_img_surface):
       
       # rotate the source image surface object with a provided angle (36 in this example).
       rotated_image = pygame.transform.rotate(src_img_surface, 36)
       
       # calculate the rotated image x, y coordinates.
       x = main_window_screen.get_width() - src_img_surface.get_width() - 100
       y = src_img_surface.get_height() + 10
       
       # draw the rotated image to the pygame app main window screen.
       update_screen(main_window_screen, rotated_image, x, y)
       
       return rotated_image
   
   # this function can rotate and scale (zoom) the image at the same time.
   def zoom_image(src_img_surface):
       
       # rotate and zoom the image with the provided parameters at the same time.
       zommed_img = pygame.transform.rotozoom(src_img_surface, -72, 0.3)
       
       # calculate the new image surface object x, y coordinates.
       x = 100
       y = main_window_screen.get_height() - 200
       
       # draw the zoomed_img to the pygame app main window.
       update_screen(main_window_screen, zommed_img, x, y)
       
       return zommed_img
       
   
   # this function listen and handle the pygame app events.
   def main_loop():
       
       while True:
           
           for event in pygame.event.get():
               
               if event.type == pygame.QUIT:
                   
                   exit()
       
   
   # this function will draw the target_surface_object to the source surface_object at the specified location.        
   def update_screen(surface_object, target_surface_object, top_left_corner_x, top_left_corner_y):
           
       surface_object.blit(target_surface_object,(top_left_corner_x, top_left_corner_y))
           
       pygame.display.update()
               
   
   
   if __name__ == '__main__':
       
       initialize_pygame()
       
       src_img = load_image()
       
       scaled_img = scale_image(src_img)
       
       rotated_img = rotate_image(scaled_img)
       
       zommed_img = zoom_image(rotated_img)
       
       main_loop()

3. When you run the above example source code, you can get the below image.