CODEWITHSUNDEEP
pythonimagerotationpygame
Michael Duffett
Michael Duffett

Reputation: 87

Rotating An Image In Pygame Without Distortion

I have been trying to make an image rotate in pygame, using python 3.6, however when I do it either distorts the image into an unrecognizable image, or when it rotates it bumps all over the place

Just using pygame.transform.rotate(image, angle) makes the distorted mess. And using something like: pygame.draw.rect(gameDisplay, self.color, [self.x, self.y, self.width, self.height]) makes the image bump all over the place.

I have looked at many questions on this site and others and so far none of them have worked perfectly. To anyone who is interested here is the link to my code so far. https://pastebin.com/UQJJFNTy My image is 64x64. Thanks in advance!

Upvotes: 0

Views: 3932

Answers (2)

skrx
skrx

Reputation: 20438

Here's a complete example. Don't modify the original image and in the while loop use pygame.transform.rotate or rotozoom to get a new rotated surface and assign it to another name. Use a rect to keep the center.

import sys
import pygame as pg


pg.init()
screen = pg.display.set_mode((640, 480))

BG_COLOR = pg.Color('darkslategray')
# Here I just create an image with per-pixel alpha and draw
# some shapes on it so that we can better see the rotation effects.
ORIG_IMAGE = pg.Surface((240, 180), pg.SRCALPHA)
pg.draw.rect(ORIG_IMAGE, pg.Color('aquamarine3'), (80, 0, 80, 180))
pg.draw.rect(ORIG_IMAGE, pg.Color('gray16'), (60, 0, 120, 40))
pg.draw.circle(ORIG_IMAGE, pg.Color('gray16'), (120, 180), 50)


def main():
    clock = pg.time.Clock()
    # The rect where we'll blit the image.
    rect = ORIG_IMAGE.get_rect(center=(300, 220))
    angle = 0

    done = False
    while not done:
        for event in pg.event.get():
            if event.type == pg.QUIT:
                done = True

        # Increment the angle, then rotate the image.
        angle += 2
        # image = pg.transform.rotate(ORIG_IMAGE, angle)  # rotate often looks ugly.
        image = pg.transform.rotozoom(ORIG_IMAGE, angle, 1)  # rotozoom is smoother.
        # The center of the new rect is the center of the old rect.
        rect = image.get_rect(center=rect.center)
        screen.fill(BG_COLOR)
        screen.blit(image, rect)

        pg.display.flip()
        clock.tick(30)


if __name__ == '__main__':
    main()
    pg.quit()
    sys.exit()

Upvotes: 2

Chris
Chris

Reputation: 898

Per the docs (http://www.pygame.org/docs/ref/transform.html):

Some of the transforms are considered destructive. These means every time they are performed they lose pixel data. Common examples of this are resizing and rotating. For this reason, it is better to re-transform the original surface than to keep transforming an image multiple times.

Each time you call transform.rotate you need to do it on the original image, not on the previously rotated one. For example, if I want the image rotated 10 degrees each frame:

image = pygame.image.load("myimage.png").convert()
image_clean = image.copy()
rot = 0

Then in your game loop (or object's update):

rot += 10
image = pygame.transform.rotate(image_clean, rot)

Upvotes: 4

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