Rotating image in pygame - python

So I have an arrow as an image. By the looks of it, it seems to be rotating right around the centre. But when it rotates, either way, when it his an angle of around 75 degrees on each side there is an error:
ValueError: subsurface rectangle outside surface area
I'm not sure what the problem is, I got the rotating function off of pygames website.
If anyone knows what the problem is, I'd really appreciate your help.
Here's the code:
screen = pygame.display.set_mode(ss)
arrow = pygame.image.load("obj.png").convert_alpha()
x = 400
y= 300
a = 0
turn = 2
def rot_center(image, angle):
"""rotate an image while keeping its center and size"""
orig_rect = image.get_rect()
rot_image = pygame.transform.rotate(image, angle)
rot_rect = orig_rect.copy()
rot_rect.center = rot_image.get_rect().center
rot_image = rot_image.subsurface(rot_rect).copy()
return rot_image
while True:
screen.fill((255, 255, 255))
if turn == 1:
a += 10
if turn == 2:
a -=10
if a == 90:
turn = 2
if a == -90:
turn = 1
rotarrow = rot_center(arrow, a)
screen.blit(rotarrow, (x, y))
pygame.display.update()
sleep(0.1)

The first function on that page, is for square images only.
For arbitrary dimensions, use the second one:
def rot_center(image, rect, angle):
"""rotate an image while keeping its center"""
rot_image = pygame.transform.rotate(image, angle)
rot_rect = rot_image.get_rect(center=rect.center)
return rot_image,rot_rect

Related

Why Does Rotating an Image in Python More Than 90 Degrees Make the Image Trail Off? [duplicate]

I had been trying to rotate an image around its center in using pygame.transform.rotate() but it's not working. Specifically the part that hangs is rot_image = rot_image.subsurface(rot_rect).copy(). I get the exception:
ValueError: subsurface rectangle outside surface area
Here is the code used to rotate an image:
def rot_center(image, angle):
"""rotate an image while keeping its center and size"""
orig_rect = image.get_rect()
rot_image = pygame.transform.rotate(image, angle)
rot_rect = orig_rect.copy()
rot_rect.center = rot_image.get_rect().center
rot_image = rot_image.subsurface(rot_rect).copy()
return rot_image
Short answer:
When you use pygame.transform.rotate the size of the new rotated image is increased compared to the size of the original image. You must make sure that the rotated image is placed so that its center remains in the center of the non-rotated image. To do this, get the rectangle of the original image and set the position. Get the rectangle of the rotated image and set the center position through the center of the original rectangle.
Returns a tuple from the function red_center, with the rotated image and the bounding rectangle of the rotated image:
def rot_center(image, angle, x, y):
rotated_image = pygame.transform.rotate(image, angle)
new_rect = rotated_image.get_rect(center = image.get_rect(center = (x, y)).center)
return rotated_image, new_rect
Or write a function which rotates and .blit the image:
def blitRotateCenter(surf, image, topleft, angle):
rotated_image = pygame.transform.rotate(image, angle)
new_rect = rotated_image.get_rect(center = image.get_rect(topleft = topleft).center)
surf.blit(rotated_image, new_rect)
Long answer:
An image (pygame.Surface) can be rotated by pygame.transform.rotate.
If that is done progressively in a loop, then the image gets distorted and rapidly increases:
while not done:
# [...]
image = pygame.transform.rotate(image, 1)
screen.blit(image, pos)
pygame.display.flip()
This is because the bounding rectangle of a rotated image is always greater than the bounding rectangle of the original image (except some rotations by multiples of 90 degrees).
The image gets distort because of the multiply copies. Each rotation generates a small error (inaccuracy). The sum of the errors is growing and the images decays.
That can be fixed by keeping the original image and "blit" an image which was generated by a single rotation operation form the original image.
angle = 0
while not done:
# [...]
rotated_image = pygame.transform.rotate(image, angle)
angle += 1
screen.blit(rotated_image, pos)
pygame.display.flip()
Now the image seems to arbitrary change its position, because the size of the image changes by the rotation and origin is always the top left of the bounding rectangle of the image.
This can be compensated by comparing the axis aligned bounding box of the image before the rotation and after the rotation.
For the following math pygame.math.Vector2 is used. Note in screen coordinates the y points down the screen, but the mathematical y axis points form the bottom to the top. This causes that the y axis has to be "flipped" during calculations
Set up a list with the 4 corner points of the bounding box:
w, h = image.get_size()
box = [pygame.math.Vector2(p) for p in [(0, 0), (w, 0), (w, -h), (0, -h)]]
Rotate the vectors to the corner points by pygame.math.Vector2.rotate:
box_rotate = [p.rotate(angle) for p in box]
Get the minimum and the maximum of the rotated points:
min_box = (min(box_rotate, key=lambda p: p[0])[0], min(box_rotate, key=lambda p: p[1])[1])
max_box = (max(box_rotate, key=lambda p: p[0])[0], max(box_rotate, key=lambda p: p[1])[1])
Calculate the "compensated" origin of the upper left point of the image by adding the minimum of the rotated box to the position. For the y coordinate max_box[1] is the minimum, because of the "flipping" along the y axis:
origin = (pos[0] + min_box[0], pos[1] - max_box[1])
rotated_image = pygame.transform.rotate(image, angle)
screen.blit(rotated_image, origin)
It is even possible to define a pivot on the original image. Compute the offset vector from the center of the image to the pivot and rotate the vector. A vector can be represented by pygame.math.Vector2 and can be rotated with pygame.math.Vector2.rotate. Notice that pygame.math.Vector2.rotate rotates in the opposite direction than pygame.transform.rotate. Therefore the angle has to be inverted:
Compute the vector from the center of the image to the pivot:
image_rect = image.get_rect(topleft = (pos[0] - originPos[0], pos[1]-originPos[1]))
offset_center_to_pivot = pygame.math.Vector2(pos) - image_rect.center
Rotate the vector
rotated_offset = offset_center_to_pivot.rotate(-angle)
Calculate the center of the rotated image:
rotated_image_center = (pos[0] - rotated_offset.x, pos[1] - rotated_offset.y)
Rotate and blit the image:
rotated_image = pygame.transform.rotate(image, angle)
rotated_image_rect = rotated_image.get_rect(center = rotated_image_center)
screen.blit(rotated_image, rotated_image_rect)
In the following example program, the function blitRotate(surf, image, pos, originPos, angle) does all the above steps and "blit" a rotated image to a surface.
surf is the target Surface
image is the Surface which has to be rotated and blit
pos is the position of the pivot on the target Surface surf (relative to the top left of surf)
originPos is position of the pivot on the image Surface (relative to the top left of image)
angle is the angle of rotation in degrees
This means, the 2nd argument (pos) of blitRotate is the position of the pivot point in the window and the 3rd argument (originPos) is the position of the pivot point on the rotating Surface:
Minimal example: repl.it/#Rabbid76/PyGame-RotateAroundPivot
import pygame
pygame.init()
screen = pygame.display.set_mode((300, 300))
clock = pygame.time.Clock()
def blitRotate(surf, image, pos, originPos, angle):
# offset from pivot to center
image_rect = image.get_rect(topleft = (pos[0] - originPos[0], pos[1]-originPos[1]))
offset_center_to_pivot = pygame.math.Vector2(pos) - image_rect.center
# roatated offset from pivot to center
rotated_offset = offset_center_to_pivot.rotate(-angle)
# roatetd image center
rotated_image_center = (pos[0] - rotated_offset.x, pos[1] - rotated_offset.y)
# get a rotated image
rotated_image = pygame.transform.rotate(image, angle)
rotated_image_rect = rotated_image.get_rect(center = rotated_image_center)
# rotate and blit the image
surf.blit(rotated_image, rotated_image_rect)
# draw rectangle around the image
pygame.draw.rect(surf, (255, 0, 0), (*rotated_image_rect.topleft, *rotated_image.get_size()),2)
def blitRotate2(surf, image, topleft, angle):
rotated_image = pygame.transform.rotate(image, angle)
new_rect = rotated_image.get_rect(center = image.get_rect(topleft = topleft).center)
surf.blit(rotated_image, new_rect.topleft)
pygame.draw.rect(surf, (255, 0, 0), new_rect, 2)
try:
image = pygame.image.load('AirPlaneFront.png')
except:
text = pygame.font.SysFont('Times New Roman', 50).render('image', False, (255, 255, 0))
image = pygame.Surface((text.get_width()+1, text.get_height()+1))
pygame.draw.rect(image, (0, 0, 255), (1, 1, *text.get_size()))
image.blit(text, (1, 1))
w, h = image.get_size()
angle = 0
done = False
while not done:
clock.tick(60)
for event in pygame.event.get():
if event.type == pygame.QUIT:
done = True
pos = (screen.get_width()/2, screen.get_height()/2)
screen.fill(0)
blitRotate(screen, image, pos, (w/2, h/2), angle)
#blitRotate2(screen, image, pos, angle)
angle += 1
pygame.draw.line(screen, (0, 255, 0), (pos[0]-20, pos[1]), (pos[0]+20, pos[1]), 3)
pygame.draw.line(screen, (0, 255, 0), (pos[0], pos[1]-20), (pos[0], pos[1]+20), 3)
pygame.draw.circle(screen, (0, 255, 0), pos, 7, 0)
pygame.display.flip()
pygame.quit()
exit()
See also Rotate surface and the answers to the questions:
How can you rotate an image around an off center pivot in Pygame
How to rotate an image around its center while its scale is getting larger(in Pygame)
How to rotate an image(player) to the mouse direction?
How to set the pivot point (center of rotation) for pygame.transform.rotate()?
How do you point the barrel towards mouse in pygame?
There are some problems with the top answer: The position of the previous rect needs to be available in the function, so that we can assign it to the new rect, e.g.:
rect = new_image.get_rect(center=rect.center)
In the other answer the location is obtained by creating a new rect from the original image, but that means it will be positioned at the default (0, 0) coordinates.
The example below should work correctly. The new rect needs the center position of the old rect, so we pass it as well to the function. Then rotate the image, call get_rect to get a new rect with the correct size and pass the center attribute of the old rect as the center argument. Finally, return both the rotated image and the new rect as a tuple and unpack it in the main loop.
import pygame as pg
def rotate(image, rect, angle):
"""Rotate the image while keeping its center."""
# Rotate the original image without modifying it.
new_image = pg.transform.rotate(image, angle)
# Get a new rect with the center of the old rect.
rect = new_image.get_rect(center=rect.center)
return new_image, rect
def main():
clock = pg.time.Clock()
screen = pg.display.set_mode((640, 480))
gray = pg.Color('gray15')
blue = pg.Color('dodgerblue2')
image = pg.Surface((320, 200), pg.SRCALPHA)
pg.draw.polygon(image, blue, ((0, 0), (320, 100), (0, 200)))
# Keep a reference to the original to preserve the image quality.
orig_image = image
rect = image.get_rect(center=(320, 240))
angle = 0
done = False
while not done:
for event in pg.event.get():
if event.type == pg.QUIT:
done = True
angle += 2
image, rect = rotate(orig_image, rect, angle)
screen.fill(gray)
screen.blit(image, rect)
pg.display.flip()
clock.tick(30)
if __name__ == '__main__':
pg.init()
main()
pg.quit()
Here's another example with a rotating pygame sprite.
import pygame as pg
class Entity(pg.sprite.Sprite):
def __init__(self, pos):
super().__init__()
self.image = pg.Surface((122, 70), pg.SRCALPHA)
pg.draw.polygon(self.image, pg.Color('dodgerblue1'),
((1, 0), (120, 35), (1, 70)))
# A reference to the original image to preserve the quality.
self.orig_image = self.image
self.rect = self.image.get_rect(center=pos)
self.angle = 0
def update(self):
self.angle += 2
self.rotate()
def rotate(self):
"""Rotate the image of the sprite around its center."""
# `rotozoom` usually looks nicer than `rotate`. Pygame's rotation
# functions return new images and don't modify the originals.
self.image = pg.transform.rotozoom(self.orig_image, self.angle, 1)
# Create a new rect with the center of the old rect.
self.rect = self.image.get_rect(center=self.rect.center)
def main():
screen = pg.display.set_mode((640, 480))
clock = pg.time.Clock()
all_sprites = pg.sprite.Group(Entity((320, 240)))
while True:
for event in pg.event.get():
if event.type == pg.QUIT:
return
all_sprites.update()
screen.fill((30, 30, 30))
all_sprites.draw(screen)
pg.display.flip()
clock.tick(30)
if __name__ == '__main__':
pg.init()
main()
pg.quit()
You are deleting the rect that rotate creates. You need to preserve rect, since it changes size when rotated.
If you want to preserve the objects location, do:
def rot_center(image, angle):
"""rotate a Surface, maintaining position."""
loc = image.get_rect().center #rot_image is not defined
rot_sprite = pygame.transform.rotate(image, angle)
rot_sprite.get_rect().center = loc
return rot_sprite
# or return tuple: (Surface, Rect)
# return rot_sprite, rot_sprite.get_rect()
Found the problem: Example works good, but needs equal dimensions for width and height. Fixed pictures and it works.
Everything you need for drawing an image in pygame
game_display = pygame.display.set_mode((800, 600))
x = 0
y = 0
angle = 0
img = pygame.image.load("resources/image.png")
img = pygame.transform.scale(img, (50, 50)) # image size
def draw_img(self, image, x, y, angle):
rotated_image = pygame.transform.rotate(image, angle)
game_display.blit(rotated_image, rotated_image.get_rect(center=image.get_rect(topleft=(x, y)).center).topleft)
# run this method with your loop
def tick():
draw_img(img, x, y, angle)
I had to modify skrx solution as below, this way works for me.
angle=0
roll = true
while roll:
# clean surface with your background color
gameDisplay.fill(color)
self.image = yourImage
rotate_image = pygame.transform.rotate(self.image, angle)
rect = rotate_image.get_rect()
pos = (((your_surface_width - rect.width)/2),((your_surface_height - rect.height)/2))
gameDisplay.blit(rotate_image,pos)
pygame.display.flip()
angle+=2
if angle == 360:
roll=False

How can I access the angle in this class? [duplicate]

I had been trying to rotate an image around its center in using pygame.transform.rotate() but it's not working. Specifically the part that hangs is rot_image = rot_image.subsurface(rot_rect).copy(). I get the exception:
ValueError: subsurface rectangle outside surface area
Here is the code used to rotate an image:
def rot_center(image, angle):
"""rotate an image while keeping its center and size"""
orig_rect = image.get_rect()
rot_image = pygame.transform.rotate(image, angle)
rot_rect = orig_rect.copy()
rot_rect.center = rot_image.get_rect().center
rot_image = rot_image.subsurface(rot_rect).copy()
return rot_image
Short answer:
When you use pygame.transform.rotate the size of the new rotated image is increased compared to the size of the original image. You must make sure that the rotated image is placed so that its center remains in the center of the non-rotated image. To do this, get the rectangle of the original image and set the position. Get the rectangle of the rotated image and set the center position through the center of the original rectangle.
Returns a tuple from the function red_center, with the rotated image and the bounding rectangle of the rotated image:
def rot_center(image, angle, x, y):
rotated_image = pygame.transform.rotate(image, angle)
new_rect = rotated_image.get_rect(center = image.get_rect(center = (x, y)).center)
return rotated_image, new_rect
Or write a function which rotates and .blit the image:
def blitRotateCenter(surf, image, topleft, angle):
rotated_image = pygame.transform.rotate(image, angle)
new_rect = rotated_image.get_rect(center = image.get_rect(topleft = topleft).center)
surf.blit(rotated_image, new_rect)
Long answer:
An image (pygame.Surface) can be rotated by pygame.transform.rotate.
If that is done progressively in a loop, then the image gets distorted and rapidly increases:
while not done:
# [...]
image = pygame.transform.rotate(image, 1)
screen.blit(image, pos)
pygame.display.flip()
This is because the bounding rectangle of a rotated image is always greater than the bounding rectangle of the original image (except some rotations by multiples of 90 degrees).
The image gets distort because of the multiply copies. Each rotation generates a small error (inaccuracy). The sum of the errors is growing and the images decays.
That can be fixed by keeping the original image and "blit" an image which was generated by a single rotation operation form the original image.
angle = 0
while not done:
# [...]
rotated_image = pygame.transform.rotate(image, angle)
angle += 1
screen.blit(rotated_image, pos)
pygame.display.flip()
Now the image seems to arbitrary change its position, because the size of the image changes by the rotation and origin is always the top left of the bounding rectangle of the image.
This can be compensated by comparing the axis aligned bounding box of the image before the rotation and after the rotation.
For the following math pygame.math.Vector2 is used. Note in screen coordinates the y points down the screen, but the mathematical y axis points form the bottom to the top. This causes that the y axis has to be "flipped" during calculations
Set up a list with the 4 corner points of the bounding box:
w, h = image.get_size()
box = [pygame.math.Vector2(p) for p in [(0, 0), (w, 0), (w, -h), (0, -h)]]
Rotate the vectors to the corner points by pygame.math.Vector2.rotate:
box_rotate = [p.rotate(angle) for p in box]
Get the minimum and the maximum of the rotated points:
min_box = (min(box_rotate, key=lambda p: p[0])[0], min(box_rotate, key=lambda p: p[1])[1])
max_box = (max(box_rotate, key=lambda p: p[0])[0], max(box_rotate, key=lambda p: p[1])[1])
Calculate the "compensated" origin of the upper left point of the image by adding the minimum of the rotated box to the position. For the y coordinate max_box[1] is the minimum, because of the "flipping" along the y axis:
origin = (pos[0] + min_box[0], pos[1] - max_box[1])
rotated_image = pygame.transform.rotate(image, angle)
screen.blit(rotated_image, origin)
It is even possible to define a pivot on the original image. Compute the offset vector from the center of the image to the pivot and rotate the vector. A vector can be represented by pygame.math.Vector2 and can be rotated with pygame.math.Vector2.rotate. Notice that pygame.math.Vector2.rotate rotates in the opposite direction than pygame.transform.rotate. Therefore the angle has to be inverted:
Compute the vector from the center of the image to the pivot:
image_rect = image.get_rect(topleft = (pos[0] - originPos[0], pos[1]-originPos[1]))
offset_center_to_pivot = pygame.math.Vector2(pos) - image_rect.center
Rotate the vector
rotated_offset = offset_center_to_pivot.rotate(-angle)
Calculate the center of the rotated image:
rotated_image_center = (pos[0] - rotated_offset.x, pos[1] - rotated_offset.y)
Rotate and blit the image:
rotated_image = pygame.transform.rotate(image, angle)
rotated_image_rect = rotated_image.get_rect(center = rotated_image_center)
screen.blit(rotated_image, rotated_image_rect)
In the following example program, the function blitRotate(surf, image, pos, originPos, angle) does all the above steps and "blit" a rotated image to a surface.
surf is the target Surface
image is the Surface which has to be rotated and blit
pos is the position of the pivot on the target Surface surf (relative to the top left of surf)
originPos is position of the pivot on the image Surface (relative to the top left of image)
angle is the angle of rotation in degrees
This means, the 2nd argument (pos) of blitRotate is the position of the pivot point in the window and the 3rd argument (originPos) is the position of the pivot point on the rotating Surface:
Minimal example: repl.it/#Rabbid76/PyGame-RotateAroundPivot
import pygame
pygame.init()
screen = pygame.display.set_mode((300, 300))
clock = pygame.time.Clock()
def blitRotate(surf, image, pos, originPos, angle):
# offset from pivot to center
image_rect = image.get_rect(topleft = (pos[0] - originPos[0], pos[1]-originPos[1]))
offset_center_to_pivot = pygame.math.Vector2(pos) - image_rect.center
# roatated offset from pivot to center
rotated_offset = offset_center_to_pivot.rotate(-angle)
# roatetd image center
rotated_image_center = (pos[0] - rotated_offset.x, pos[1] - rotated_offset.y)
# get a rotated image
rotated_image = pygame.transform.rotate(image, angle)
rotated_image_rect = rotated_image.get_rect(center = rotated_image_center)
# rotate and blit the image
surf.blit(rotated_image, rotated_image_rect)
# draw rectangle around the image
pygame.draw.rect(surf, (255, 0, 0), (*rotated_image_rect.topleft, *rotated_image.get_size()),2)
def blitRotate2(surf, image, topleft, angle):
rotated_image = pygame.transform.rotate(image, angle)
new_rect = rotated_image.get_rect(center = image.get_rect(topleft = topleft).center)
surf.blit(rotated_image, new_rect.topleft)
pygame.draw.rect(surf, (255, 0, 0), new_rect, 2)
try:
image = pygame.image.load('AirPlaneFront.png')
except:
text = pygame.font.SysFont('Times New Roman', 50).render('image', False, (255, 255, 0))
image = pygame.Surface((text.get_width()+1, text.get_height()+1))
pygame.draw.rect(image, (0, 0, 255), (1, 1, *text.get_size()))
image.blit(text, (1, 1))
w, h = image.get_size()
angle = 0
done = False
while not done:
clock.tick(60)
for event in pygame.event.get():
if event.type == pygame.QUIT:
done = True
pos = (screen.get_width()/2, screen.get_height()/2)
screen.fill(0)
blitRotate(screen, image, pos, (w/2, h/2), angle)
#blitRotate2(screen, image, pos, angle)
angle += 1
pygame.draw.line(screen, (0, 255, 0), (pos[0]-20, pos[1]), (pos[0]+20, pos[1]), 3)
pygame.draw.line(screen, (0, 255, 0), (pos[0], pos[1]-20), (pos[0], pos[1]+20), 3)
pygame.draw.circle(screen, (0, 255, 0), pos, 7, 0)
pygame.display.flip()
pygame.quit()
exit()
See also Rotate surface and the answers to the questions:
How can you rotate an image around an off center pivot in Pygame
How to rotate an image around its center while its scale is getting larger(in Pygame)
How to rotate an image(player) to the mouse direction?
How to set the pivot point (center of rotation) for pygame.transform.rotate()?
How do you point the barrel towards mouse in pygame?
There are some problems with the top answer: The position of the previous rect needs to be available in the function, so that we can assign it to the new rect, e.g.:
rect = new_image.get_rect(center=rect.center)
In the other answer the location is obtained by creating a new rect from the original image, but that means it will be positioned at the default (0, 0) coordinates.
The example below should work correctly. The new rect needs the center position of the old rect, so we pass it as well to the function. Then rotate the image, call get_rect to get a new rect with the correct size and pass the center attribute of the old rect as the center argument. Finally, return both the rotated image and the new rect as a tuple and unpack it in the main loop.
import pygame as pg
def rotate(image, rect, angle):
"""Rotate the image while keeping its center."""
# Rotate the original image without modifying it.
new_image = pg.transform.rotate(image, angle)
# Get a new rect with the center of the old rect.
rect = new_image.get_rect(center=rect.center)
return new_image, rect
def main():
clock = pg.time.Clock()
screen = pg.display.set_mode((640, 480))
gray = pg.Color('gray15')
blue = pg.Color('dodgerblue2')
image = pg.Surface((320, 200), pg.SRCALPHA)
pg.draw.polygon(image, blue, ((0, 0), (320, 100), (0, 200)))
# Keep a reference to the original to preserve the image quality.
orig_image = image
rect = image.get_rect(center=(320, 240))
angle = 0
done = False
while not done:
for event in pg.event.get():
if event.type == pg.QUIT:
done = True
angle += 2
image, rect = rotate(orig_image, rect, angle)
screen.fill(gray)
screen.blit(image, rect)
pg.display.flip()
clock.tick(30)
if __name__ == '__main__':
pg.init()
main()
pg.quit()
Here's another example with a rotating pygame sprite.
import pygame as pg
class Entity(pg.sprite.Sprite):
def __init__(self, pos):
super().__init__()
self.image = pg.Surface((122, 70), pg.SRCALPHA)
pg.draw.polygon(self.image, pg.Color('dodgerblue1'),
((1, 0), (120, 35), (1, 70)))
# A reference to the original image to preserve the quality.
self.orig_image = self.image
self.rect = self.image.get_rect(center=pos)
self.angle = 0
def update(self):
self.angle += 2
self.rotate()
def rotate(self):
"""Rotate the image of the sprite around its center."""
# `rotozoom` usually looks nicer than `rotate`. Pygame's rotation
# functions return new images and don't modify the originals.
self.image = pg.transform.rotozoom(self.orig_image, self.angle, 1)
# Create a new rect with the center of the old rect.
self.rect = self.image.get_rect(center=self.rect.center)
def main():
screen = pg.display.set_mode((640, 480))
clock = pg.time.Clock()
all_sprites = pg.sprite.Group(Entity((320, 240)))
while True:
for event in pg.event.get():
if event.type == pg.QUIT:
return
all_sprites.update()
screen.fill((30, 30, 30))
all_sprites.draw(screen)
pg.display.flip()
clock.tick(30)
if __name__ == '__main__':
pg.init()
main()
pg.quit()
You are deleting the rect that rotate creates. You need to preserve rect, since it changes size when rotated.
If you want to preserve the objects location, do:
def rot_center(image, angle):
"""rotate a Surface, maintaining position."""
loc = image.get_rect().center #rot_image is not defined
rot_sprite = pygame.transform.rotate(image, angle)
rot_sprite.get_rect().center = loc
return rot_sprite
# or return tuple: (Surface, Rect)
# return rot_sprite, rot_sprite.get_rect()
Found the problem: Example works good, but needs equal dimensions for width and height. Fixed pictures and it works.
Everything you need for drawing an image in pygame
game_display = pygame.display.set_mode((800, 600))
x = 0
y = 0
angle = 0
img = pygame.image.load("resources/image.png")
img = pygame.transform.scale(img, (50, 50)) # image size
def draw_img(self, image, x, y, angle):
rotated_image = pygame.transform.rotate(image, angle)
game_display.blit(rotated_image, rotated_image.get_rect(center=image.get_rect(topleft=(x, y)).center).topleft)
# run this method with your loop
def tick():
draw_img(img, x, y, angle)
I had to modify skrx solution as below, this way works for me.
angle=0
roll = true
while roll:
# clean surface with your background color
gameDisplay.fill(color)
self.image = yourImage
rotate_image = pygame.transform.rotate(self.image, angle)
rect = rotate_image.get_rect()
pos = (((your_surface_width - rect.width)/2),((your_surface_height - rect.height)/2))
gameDisplay.blit(rotate_image,pos)
pygame.display.flip()
angle+=2
if angle == 360:
roll=False

Pygame rect just expands and contracts when I try to rotate it? [duplicate]

I had been trying to rotate an image around its center in using pygame.transform.rotate() but it's not working. Specifically the part that hangs is rot_image = rot_image.subsurface(rot_rect).copy(). I get the exception:
ValueError: subsurface rectangle outside surface area
Here is the code used to rotate an image:
def rot_center(image, angle):
"""rotate an image while keeping its center and size"""
orig_rect = image.get_rect()
rot_image = pygame.transform.rotate(image, angle)
rot_rect = orig_rect.copy()
rot_rect.center = rot_image.get_rect().center
rot_image = rot_image.subsurface(rot_rect).copy()
return rot_image
Short answer:
When you use pygame.transform.rotate the size of the new rotated image is increased compared to the size of the original image. You must make sure that the rotated image is placed so that its center remains in the center of the non-rotated image. To do this, get the rectangle of the original image and set the position. Get the rectangle of the rotated image and set the center position through the center of the original rectangle.
Returns a tuple from the function red_center, with the rotated image and the bounding rectangle of the rotated image:
def rot_center(image, angle, x, y):
rotated_image = pygame.transform.rotate(image, angle)
new_rect = rotated_image.get_rect(center = image.get_rect(center = (x, y)).center)
return rotated_image, new_rect
Or write a function which rotates and .blit the image:
def blitRotateCenter(surf, image, topleft, angle):
rotated_image = pygame.transform.rotate(image, angle)
new_rect = rotated_image.get_rect(center = image.get_rect(topleft = topleft).center)
surf.blit(rotated_image, new_rect)
Long answer:
An image (pygame.Surface) can be rotated by pygame.transform.rotate.
If that is done progressively in a loop, then the image gets distorted and rapidly increases:
while not done:
# [...]
image = pygame.transform.rotate(image, 1)
screen.blit(image, pos)
pygame.display.flip()
This is because the bounding rectangle of a rotated image is always greater than the bounding rectangle of the original image (except some rotations by multiples of 90 degrees).
The image gets distort because of the multiply copies. Each rotation generates a small error (inaccuracy). The sum of the errors is growing and the images decays.
That can be fixed by keeping the original image and "blit" an image which was generated by a single rotation operation form the original image.
angle = 0
while not done:
# [...]
rotated_image = pygame.transform.rotate(image, angle)
angle += 1
screen.blit(rotated_image, pos)
pygame.display.flip()
Now the image seems to arbitrary change its position, because the size of the image changes by the rotation and origin is always the top left of the bounding rectangle of the image.
This can be compensated by comparing the axis aligned bounding box of the image before the rotation and after the rotation.
For the following math pygame.math.Vector2 is used. Note in screen coordinates the y points down the screen, but the mathematical y axis points form the bottom to the top. This causes that the y axis has to be "flipped" during calculations
Set up a list with the 4 corner points of the bounding box:
w, h = image.get_size()
box = [pygame.math.Vector2(p) for p in [(0, 0), (w, 0), (w, -h), (0, -h)]]
Rotate the vectors to the corner points by pygame.math.Vector2.rotate:
box_rotate = [p.rotate(angle) for p in box]
Get the minimum and the maximum of the rotated points:
min_box = (min(box_rotate, key=lambda p: p[0])[0], min(box_rotate, key=lambda p: p[1])[1])
max_box = (max(box_rotate, key=lambda p: p[0])[0], max(box_rotate, key=lambda p: p[1])[1])
Calculate the "compensated" origin of the upper left point of the image by adding the minimum of the rotated box to the position. For the y coordinate max_box[1] is the minimum, because of the "flipping" along the y axis:
origin = (pos[0] + min_box[0], pos[1] - max_box[1])
rotated_image = pygame.transform.rotate(image, angle)
screen.blit(rotated_image, origin)
It is even possible to define a pivot on the original image. Compute the offset vector from the center of the image to the pivot and rotate the vector. A vector can be represented by pygame.math.Vector2 and can be rotated with pygame.math.Vector2.rotate. Notice that pygame.math.Vector2.rotate rotates in the opposite direction than pygame.transform.rotate. Therefore the angle has to be inverted:
Compute the vector from the center of the image to the pivot:
image_rect = image.get_rect(topleft = (pos[0] - originPos[0], pos[1]-originPos[1]))
offset_center_to_pivot = pygame.math.Vector2(pos) - image_rect.center
Rotate the vector
rotated_offset = offset_center_to_pivot.rotate(-angle)
Calculate the center of the rotated image:
rotated_image_center = (pos[0] - rotated_offset.x, pos[1] - rotated_offset.y)
Rotate and blit the image:
rotated_image = pygame.transform.rotate(image, angle)
rotated_image_rect = rotated_image.get_rect(center = rotated_image_center)
screen.blit(rotated_image, rotated_image_rect)
In the following example program, the function blitRotate(surf, image, pos, originPos, angle) does all the above steps and "blit" a rotated image to a surface.
surf is the target Surface
image is the Surface which has to be rotated and blit
pos is the position of the pivot on the target Surface surf (relative to the top left of surf)
originPos is position of the pivot on the image Surface (relative to the top left of image)
angle is the angle of rotation in degrees
This means, the 2nd argument (pos) of blitRotate is the position of the pivot point in the window and the 3rd argument (originPos) is the position of the pivot point on the rotating Surface:
Minimal example: repl.it/#Rabbid76/PyGame-RotateAroundPivot
import pygame
pygame.init()
screen = pygame.display.set_mode((300, 300))
clock = pygame.time.Clock()
def blitRotate(surf, image, pos, originPos, angle):
# offset from pivot to center
image_rect = image.get_rect(topleft = (pos[0] - originPos[0], pos[1]-originPos[1]))
offset_center_to_pivot = pygame.math.Vector2(pos) - image_rect.center
# roatated offset from pivot to center
rotated_offset = offset_center_to_pivot.rotate(-angle)
# roatetd image center
rotated_image_center = (pos[0] - rotated_offset.x, pos[1] - rotated_offset.y)
# get a rotated image
rotated_image = pygame.transform.rotate(image, angle)
rotated_image_rect = rotated_image.get_rect(center = rotated_image_center)
# rotate and blit the image
surf.blit(rotated_image, rotated_image_rect)
# draw rectangle around the image
pygame.draw.rect(surf, (255, 0, 0), (*rotated_image_rect.topleft, *rotated_image.get_size()),2)
def blitRotate2(surf, image, topleft, angle):
rotated_image = pygame.transform.rotate(image, angle)
new_rect = rotated_image.get_rect(center = image.get_rect(topleft = topleft).center)
surf.blit(rotated_image, new_rect.topleft)
pygame.draw.rect(surf, (255, 0, 0), new_rect, 2)
try:
image = pygame.image.load('AirPlaneFront.png')
except:
text = pygame.font.SysFont('Times New Roman', 50).render('image', False, (255, 255, 0))
image = pygame.Surface((text.get_width()+1, text.get_height()+1))
pygame.draw.rect(image, (0, 0, 255), (1, 1, *text.get_size()))
image.blit(text, (1, 1))
w, h = image.get_size()
angle = 0
done = False
while not done:
clock.tick(60)
for event in pygame.event.get():
if event.type == pygame.QUIT:
done = True
pos = (screen.get_width()/2, screen.get_height()/2)
screen.fill(0)
blitRotate(screen, image, pos, (w/2, h/2), angle)
#blitRotate2(screen, image, pos, angle)
angle += 1
pygame.draw.line(screen, (0, 255, 0), (pos[0]-20, pos[1]), (pos[0]+20, pos[1]), 3)
pygame.draw.line(screen, (0, 255, 0), (pos[0], pos[1]-20), (pos[0], pos[1]+20), 3)
pygame.draw.circle(screen, (0, 255, 0), pos, 7, 0)
pygame.display.flip()
pygame.quit()
exit()
See also Rotate surface and the answers to the questions:
How can you rotate an image around an off center pivot in Pygame
How to rotate an image around its center while its scale is getting larger(in Pygame)
How to rotate an image(player) to the mouse direction?
How to set the pivot point (center of rotation) for pygame.transform.rotate()?
How do you point the barrel towards mouse in pygame?
There are some problems with the top answer: The position of the previous rect needs to be available in the function, so that we can assign it to the new rect, e.g.:
rect = new_image.get_rect(center=rect.center)
In the other answer the location is obtained by creating a new rect from the original image, but that means it will be positioned at the default (0, 0) coordinates.
The example below should work correctly. The new rect needs the center position of the old rect, so we pass it as well to the function. Then rotate the image, call get_rect to get a new rect with the correct size and pass the center attribute of the old rect as the center argument. Finally, return both the rotated image and the new rect as a tuple and unpack it in the main loop.
import pygame as pg
def rotate(image, rect, angle):
"""Rotate the image while keeping its center."""
# Rotate the original image without modifying it.
new_image = pg.transform.rotate(image, angle)
# Get a new rect with the center of the old rect.
rect = new_image.get_rect(center=rect.center)
return new_image, rect
def main():
clock = pg.time.Clock()
screen = pg.display.set_mode((640, 480))
gray = pg.Color('gray15')
blue = pg.Color('dodgerblue2')
image = pg.Surface((320, 200), pg.SRCALPHA)
pg.draw.polygon(image, blue, ((0, 0), (320, 100), (0, 200)))
# Keep a reference to the original to preserve the image quality.
orig_image = image
rect = image.get_rect(center=(320, 240))
angle = 0
done = False
while not done:
for event in pg.event.get():
if event.type == pg.QUIT:
done = True
angle += 2
image, rect = rotate(orig_image, rect, angle)
screen.fill(gray)
screen.blit(image, rect)
pg.display.flip()
clock.tick(30)
if __name__ == '__main__':
pg.init()
main()
pg.quit()
Here's another example with a rotating pygame sprite.
import pygame as pg
class Entity(pg.sprite.Sprite):
def __init__(self, pos):
super().__init__()
self.image = pg.Surface((122, 70), pg.SRCALPHA)
pg.draw.polygon(self.image, pg.Color('dodgerblue1'),
((1, 0), (120, 35), (1, 70)))
# A reference to the original image to preserve the quality.
self.orig_image = self.image
self.rect = self.image.get_rect(center=pos)
self.angle = 0
def update(self):
self.angle += 2
self.rotate()
def rotate(self):
"""Rotate the image of the sprite around its center."""
# `rotozoom` usually looks nicer than `rotate`. Pygame's rotation
# functions return new images and don't modify the originals.
self.image = pg.transform.rotozoom(self.orig_image, self.angle, 1)
# Create a new rect with the center of the old rect.
self.rect = self.image.get_rect(center=self.rect.center)
def main():
screen = pg.display.set_mode((640, 480))
clock = pg.time.Clock()
all_sprites = pg.sprite.Group(Entity((320, 240)))
while True:
for event in pg.event.get():
if event.type == pg.QUIT:
return
all_sprites.update()
screen.fill((30, 30, 30))
all_sprites.draw(screen)
pg.display.flip()
clock.tick(30)
if __name__ == '__main__':
pg.init()
main()
pg.quit()
You are deleting the rect that rotate creates. You need to preserve rect, since it changes size when rotated.
If you want to preserve the objects location, do:
def rot_center(image, angle):
"""rotate a Surface, maintaining position."""
loc = image.get_rect().center #rot_image is not defined
rot_sprite = pygame.transform.rotate(image, angle)
rot_sprite.get_rect().center = loc
return rot_sprite
# or return tuple: (Surface, Rect)
# return rot_sprite, rot_sprite.get_rect()
Found the problem: Example works good, but needs equal dimensions for width and height. Fixed pictures and it works.
Everything you need for drawing an image in pygame
game_display = pygame.display.set_mode((800, 600))
x = 0
y = 0
angle = 0
img = pygame.image.load("resources/image.png")
img = pygame.transform.scale(img, (50, 50)) # image size
def draw_img(self, image, x, y, angle):
rotated_image = pygame.transform.rotate(image, angle)
game_display.blit(rotated_image, rotated_image.get_rect(center=image.get_rect(topleft=(x, y)).center).topleft)
# run this method with your loop
def tick():
draw_img(img, x, y, angle)
I had to modify skrx solution as below, this way works for me.
angle=0
roll = true
while roll:
# clean surface with your background color
gameDisplay.fill(color)
self.image = yourImage
rotate_image = pygame.transform.rotate(self.image, angle)
rect = rotate_image.get_rect()
pos = (((your_surface_width - rect.width)/2),((your_surface_height - rect.height)/2))
gameDisplay.blit(rotate_image,pos)
pygame.display.flip()
angle+=2
if angle == 360:
roll=False

Pygame, border of image get cut while rotating

I am rotating an image in pygame.
My image is a png and have a lot of free space around it.
However, when I rotate, I can see the invisible frame around it.
How to fix this ?
I am rotating it with this code
def rot_center(image, angle):
"""rotate an image while keeping its center and size"""
orig_rect = image.get_rect()
rot_image = pygame.transform.rotate(image, angle)
rot_rect = orig_rect.copy()
rot_rect.center = rot_image.get_rect().center
rot_image = rot_image.subsurface(rot_rect).copy()
return rot_image
perso.image = pygame.image.load("sprites/[shadow]main_char_sprite.png")#.convert_alpha()
perso.image = pygame.transform.scale(perso.image, (80,80))
perso.original=perso.image #besoin d'un originial pour faire la rotation
perso.rect = perso.image.get_rect()
perso.rect.x = 200
perso.rect.y = 200
perso.add(perso_group)
counter = 0 #counter define the angle
pygame.key.set_repeat(1,1)
while 1:
screen.fill(white)
for event in pygame.event.get(): # User did something
if event.type == KEYDOWN and event.key == K_SPACE:
counter += 2
perso.image=rot_center(perso.original, counter) #counter define the angle
print "rotating now"
all_group.add(statique_group, zombie_group, perso_group)
all_group.draw(screen)
pygame.display.flip()
any idea ?
fixed !
perso.image=pygame.transform.rotate(perso.original, angle-90)
perso.rect=perso.image.get_rect(center=perso.rect.center)

How do I rotate an image around its center using Pygame?

I had been trying to rotate an image around its center in using pygame.transform.rotate() but it's not working. Specifically the part that hangs is rot_image = rot_image.subsurface(rot_rect).copy(). I get the exception:
ValueError: subsurface rectangle outside surface area
Here is the code used to rotate an image:
def rot_center(image, angle):
"""rotate an image while keeping its center and size"""
orig_rect = image.get_rect()
rot_image = pygame.transform.rotate(image, angle)
rot_rect = orig_rect.copy()
rot_rect.center = rot_image.get_rect().center
rot_image = rot_image.subsurface(rot_rect).copy()
return rot_image
Short answer:
When you use pygame.transform.rotate the size of the new rotated image is increased compared to the size of the original image. You must make sure that the rotated image is placed so that its center remains in the center of the non-rotated image. To do this, get the rectangle of the original image and set the position. Get the rectangle of the rotated image and set the center position through the center of the original rectangle.
Returns a tuple from the function red_center, with the rotated image and the bounding rectangle of the rotated image:
def rot_center(image, angle, x, y):
rotated_image = pygame.transform.rotate(image, angle)
new_rect = rotated_image.get_rect(center = image.get_rect(center = (x, y)).center)
return rotated_image, new_rect
Or write a function which rotates and .blit the image:
def blitRotateCenter(surf, image, topleft, angle):
rotated_image = pygame.transform.rotate(image, angle)
new_rect = rotated_image.get_rect(center = image.get_rect(topleft = topleft).center)
surf.blit(rotated_image, new_rect)
Long answer:
An image (pygame.Surface) can be rotated by pygame.transform.rotate.
If that is done progressively in a loop, then the image gets distorted and rapidly increases:
while not done:
# [...]
image = pygame.transform.rotate(image, 1)
screen.blit(image, pos)
pygame.display.flip()
This is because the bounding rectangle of a rotated image is always greater than the bounding rectangle of the original image (except some rotations by multiples of 90 degrees).
The image gets distort because of the multiply copies. Each rotation generates a small error (inaccuracy). The sum of the errors is growing and the images decays.
That can be fixed by keeping the original image and "blit" an image which was generated by a single rotation operation form the original image.
angle = 0
while not done:
# [...]
rotated_image = pygame.transform.rotate(image, angle)
angle += 1
screen.blit(rotated_image, pos)
pygame.display.flip()
Now the image seems to arbitrary change its position, because the size of the image changes by the rotation and origin is always the top left of the bounding rectangle of the image.
This can be compensated by comparing the axis aligned bounding box of the image before the rotation and after the rotation.
For the following math pygame.math.Vector2 is used. Note in screen coordinates the y points down the screen, but the mathematical y axis points form the bottom to the top. This causes that the y axis has to be "flipped" during calculations
Set up a list with the 4 corner points of the bounding box:
w, h = image.get_size()
box = [pygame.math.Vector2(p) for p in [(0, 0), (w, 0), (w, -h), (0, -h)]]
Rotate the vectors to the corner points by pygame.math.Vector2.rotate:
box_rotate = [p.rotate(angle) for p in box]
Get the minimum and the maximum of the rotated points:
min_box = (min(box_rotate, key=lambda p: p[0])[0], min(box_rotate, key=lambda p: p[1])[1])
max_box = (max(box_rotate, key=lambda p: p[0])[0], max(box_rotate, key=lambda p: p[1])[1])
Calculate the "compensated" origin of the upper left point of the image by adding the minimum of the rotated box to the position. For the y coordinate max_box[1] is the minimum, because of the "flipping" along the y axis:
origin = (pos[0] + min_box[0], pos[1] - max_box[1])
rotated_image = pygame.transform.rotate(image, angle)
screen.blit(rotated_image, origin)
It is even possible to define a pivot on the original image. Compute the offset vector from the center of the image to the pivot and rotate the vector. A vector can be represented by pygame.math.Vector2 and can be rotated with pygame.math.Vector2.rotate. Notice that pygame.math.Vector2.rotate rotates in the opposite direction than pygame.transform.rotate. Therefore the angle has to be inverted:
Compute the vector from the center of the image to the pivot:
image_rect = image.get_rect(topleft = (pos[0] - originPos[0], pos[1]-originPos[1]))
offset_center_to_pivot = pygame.math.Vector2(pos) - image_rect.center
Rotate the vector
rotated_offset = offset_center_to_pivot.rotate(-angle)
Calculate the center of the rotated image:
rotated_image_center = (pos[0] - rotated_offset.x, pos[1] - rotated_offset.y)
Rotate and blit the image:
rotated_image = pygame.transform.rotate(image, angle)
rotated_image_rect = rotated_image.get_rect(center = rotated_image_center)
screen.blit(rotated_image, rotated_image_rect)
In the following example program, the function blitRotate(surf, image, pos, originPos, angle) does all the above steps and "blit" a rotated image to a surface.
surf is the target Surface
image is the Surface which has to be rotated and blit
pos is the position of the pivot on the target Surface surf (relative to the top left of surf)
originPos is position of the pivot on the image Surface (relative to the top left of image)
angle is the angle of rotation in degrees
This means, the 2nd argument (pos) of blitRotate is the position of the pivot point in the window and the 3rd argument (originPos) is the position of the pivot point on the rotating Surface:
Minimal example: repl.it/#Rabbid76/PyGame-RotateAroundPivot
import pygame
pygame.init()
screen = pygame.display.set_mode((300, 300))
clock = pygame.time.Clock()
def blitRotate(surf, image, pos, originPos, angle):
# offset from pivot to center
image_rect = image.get_rect(topleft = (pos[0] - originPos[0], pos[1]-originPos[1]))
offset_center_to_pivot = pygame.math.Vector2(pos) - image_rect.center
# roatated offset from pivot to center
rotated_offset = offset_center_to_pivot.rotate(-angle)
# roatetd image center
rotated_image_center = (pos[0] - rotated_offset.x, pos[1] - rotated_offset.y)
# get a rotated image
rotated_image = pygame.transform.rotate(image, angle)
rotated_image_rect = rotated_image.get_rect(center = rotated_image_center)
# rotate and blit the image
surf.blit(rotated_image, rotated_image_rect)
# draw rectangle around the image
pygame.draw.rect(surf, (255, 0, 0), (*rotated_image_rect.topleft, *rotated_image.get_size()),2)
def blitRotate2(surf, image, topleft, angle):
rotated_image = pygame.transform.rotate(image, angle)
new_rect = rotated_image.get_rect(center = image.get_rect(topleft = topleft).center)
surf.blit(rotated_image, new_rect.topleft)
pygame.draw.rect(surf, (255, 0, 0), new_rect, 2)
try:
image = pygame.image.load('AirPlaneFront.png')
except:
text = pygame.font.SysFont('Times New Roman', 50).render('image', False, (255, 255, 0))
image = pygame.Surface((text.get_width()+1, text.get_height()+1))
pygame.draw.rect(image, (0, 0, 255), (1, 1, *text.get_size()))
image.blit(text, (1, 1))
w, h = image.get_size()
angle = 0
done = False
while not done:
clock.tick(60)
for event in pygame.event.get():
if event.type == pygame.QUIT:
done = True
pos = (screen.get_width()/2, screen.get_height()/2)
screen.fill(0)
blitRotate(screen, image, pos, (w/2, h/2), angle)
#blitRotate2(screen, image, pos, angle)
angle += 1
pygame.draw.line(screen, (0, 255, 0), (pos[0]-20, pos[1]), (pos[0]+20, pos[1]), 3)
pygame.draw.line(screen, (0, 255, 0), (pos[0], pos[1]-20), (pos[0], pos[1]+20), 3)
pygame.draw.circle(screen, (0, 255, 0), pos, 7, 0)
pygame.display.flip()
pygame.quit()
exit()
See also Rotate surface and the answers to the questions:
How can you rotate an image around an off center pivot in Pygame
How to rotate an image around its center while its scale is getting larger(in Pygame)
How to rotate an image(player) to the mouse direction?
How to set the pivot point (center of rotation) for pygame.transform.rotate()?
How do you point the barrel towards mouse in pygame?
There are some problems with the top answer: The position of the previous rect needs to be available in the function, so that we can assign it to the new rect, e.g.:
rect = new_image.get_rect(center=rect.center)
In the other answer the location is obtained by creating a new rect from the original image, but that means it will be positioned at the default (0, 0) coordinates.
The example below should work correctly. The new rect needs the center position of the old rect, so we pass it as well to the function. Then rotate the image, call get_rect to get a new rect with the correct size and pass the center attribute of the old rect as the center argument. Finally, return both the rotated image and the new rect as a tuple and unpack it in the main loop.
import pygame as pg
def rotate(image, rect, angle):
"""Rotate the image while keeping its center."""
# Rotate the original image without modifying it.
new_image = pg.transform.rotate(image, angle)
# Get a new rect with the center of the old rect.
rect = new_image.get_rect(center=rect.center)
return new_image, rect
def main():
clock = pg.time.Clock()
screen = pg.display.set_mode((640, 480))
gray = pg.Color('gray15')
blue = pg.Color('dodgerblue2')
image = pg.Surface((320, 200), pg.SRCALPHA)
pg.draw.polygon(image, blue, ((0, 0), (320, 100), (0, 200)))
# Keep a reference to the original to preserve the image quality.
orig_image = image
rect = image.get_rect(center=(320, 240))
angle = 0
done = False
while not done:
for event in pg.event.get():
if event.type == pg.QUIT:
done = True
angle += 2
image, rect = rotate(orig_image, rect, angle)
screen.fill(gray)
screen.blit(image, rect)
pg.display.flip()
clock.tick(30)
if __name__ == '__main__':
pg.init()
main()
pg.quit()
Here's another example with a rotating pygame sprite.
import pygame as pg
class Entity(pg.sprite.Sprite):
def __init__(self, pos):
super().__init__()
self.image = pg.Surface((122, 70), pg.SRCALPHA)
pg.draw.polygon(self.image, pg.Color('dodgerblue1'),
((1, 0), (120, 35), (1, 70)))
# A reference to the original image to preserve the quality.
self.orig_image = self.image
self.rect = self.image.get_rect(center=pos)
self.angle = 0
def update(self):
self.angle += 2
self.rotate()
def rotate(self):
"""Rotate the image of the sprite around its center."""
# `rotozoom` usually looks nicer than `rotate`. Pygame's rotation
# functions return new images and don't modify the originals.
self.image = pg.transform.rotozoom(self.orig_image, self.angle, 1)
# Create a new rect with the center of the old rect.
self.rect = self.image.get_rect(center=self.rect.center)
def main():
screen = pg.display.set_mode((640, 480))
clock = pg.time.Clock()
all_sprites = pg.sprite.Group(Entity((320, 240)))
while True:
for event in pg.event.get():
if event.type == pg.QUIT:
return
all_sprites.update()
screen.fill((30, 30, 30))
all_sprites.draw(screen)
pg.display.flip()
clock.tick(30)
if __name__ == '__main__':
pg.init()
main()
pg.quit()
You are deleting the rect that rotate creates. You need to preserve rect, since it changes size when rotated.
If you want to preserve the objects location, do:
def rot_center(image, angle):
"""rotate a Surface, maintaining position."""
loc = image.get_rect().center #rot_image is not defined
rot_sprite = pygame.transform.rotate(image, angle)
rot_sprite.get_rect().center = loc
return rot_sprite
# or return tuple: (Surface, Rect)
# return rot_sprite, rot_sprite.get_rect()
Found the problem: Example works good, but needs equal dimensions for width and height. Fixed pictures and it works.
Everything you need for drawing an image in pygame
game_display = pygame.display.set_mode((800, 600))
x = 0
y = 0
angle = 0
img = pygame.image.load("resources/image.png")
img = pygame.transform.scale(img, (50, 50)) # image size
def draw_img(self, image, x, y, angle):
rotated_image = pygame.transform.rotate(image, angle)
game_display.blit(rotated_image, rotated_image.get_rect(center=image.get_rect(topleft=(x, y)).center).topleft)
# run this method with your loop
def tick():
draw_img(img, x, y, angle)
I had to modify skrx solution as below, this way works for me.
angle=0
roll = true
while roll:
# clean surface with your background color
gameDisplay.fill(color)
self.image = yourImage
rotate_image = pygame.transform.rotate(self.image, angle)
rect = rotate_image.get_rect()
pos = (((your_surface_width - rect.width)/2),((your_surface_height - rect.height)/2))
gameDisplay.blit(rotate_image,pos)
pygame.display.flip()
angle+=2
if angle == 360:
roll=False

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