spritesheet.py

# This class handles sprite sheets
# This was taken from www.scriptefun.com/transcript-2-using
# sprite-sheets-and-drawing-the-background
# I've added some code to fail if the file wasn't found..
# Note: When calling images_at the rect is the format:
# (x, y, x + offset, y + offset)

# Additional notes
# - Further adaptations from https://www.pygame.org/wiki/Spritesheet
# - Cleaned up overall formatting.
# - Updated from Python 2 -> Python 3.

import pygame


class SpriteSheet:

    def __init__(self, filename):
        """Load the sheet."""
        try:
            self.sheet = pygame.image.load(filename).convert_alpha()
            self.sheet.set_colorkey(-1, pygame.RLEACCEL)
        except pygame.error as e:
            print(f"Unable to load spritesheet image: {filename}")
            raise SystemExit(e)

    def image_at(self, rectangle, colorkey=None, scale=1):
        """Load a specific image from a specific rectangle."""
        # Loads image from x, y, x+offset, y+offset.
        rect = pygame.Rect(rectangle)
        image = pygame.Surface(rect.size).convert()
        image.blit(self.sheet, (0, 0), rect)
        image = pygame.transform.scale(
            image,
            (
                rectangle[2]*scale,
                rectangle[3]*scale,
            )
        )
        if colorkey is not None:
            if colorkey == -1:
                colorkey = image.get_at((0, 0))
            image.set_colorkey(colorkey, pygame.RLEACCEL)
        return image

    def images_at(self, rects, colorkey=None, scale=1):
        """Load a whole bunch of images and return them as a list."""
        return [self.image_at(rect, colorkey, scale=scale) for rect in rects]

    def load_strip(self, rect, image_count, colorkey=None, scale=1):
        """Load a whole strip of images, and return them as a list."""
        tups = [(rect[0] + rect[2] * x, rect[1], rect[2], rect[3])
                for x in range(image_count)]
        return self.images_at(tups, colorkey, scale=scale)