only rotate part of image python

Question

Can someone tell me how to rotate only part of an image like this:

How to find coordinate / center of this image:

i can rotate all pict using this

from PIL import Image

def rotate_image():
img = Image.open("nime1.png")

img.rotate(45).save("plus45.png")
img.rotate(-45).save("minus45.png")

img.rotate(90).save("90.png")
img.transpose(Image.ROTATE_90).save("90_trans.png")

img.rotate(180).save("180.png")


if __name__ == '__main__':
rotate_image()

Try to include the picture in your question without linking to it. — gowrath
– gowrath, Commented Aug 28, 2016 at 5:20
Make a copy of the image; crop to the desired area you want to rotate, rotate it, and paste it on the original. Does that work? — gowrath
– gowrath, Commented Aug 28, 2016 at 5:27

James · Accepted Answer · 2016-08-28 06:52:50Z

1

You can crop an area of the picture as a new variable. In this case, I cropped a 120x120 pixel box out of the original image. It is rotated by 90 and then pasted back on the original.

from PIL import Image

img = Image.open('./image.jpg')
sub_image = img.crop(box=(200,0,320,120)).rotate(90)
img.paste(sub_image, box=(200,0))

So I thought about this a bit more and crafted a function that applies a circular mask to the cropped image before rotations. This allows an arbitrary angle without weird effects.

def circle_rotate(image, x, y, radius, degree):
    img_arr = numpy.asarray(image)
    box = (x-radius, y-radius, x+radius+1, y+radius+1)
    crop = image.crop(box=box)
    crop_arr = numpy.asarray(crop)
    # build the cirle mask
    mask = numpy.zeros((2*radius+1, 2*radius+1))
    for i in range(crop_arr.shape[0]):
        for j in range(crop_arr.shape[1]):
            if (i-radius)**2 + (j-radius)**2 <= radius**2:
                mask[i,j] = 1
    # create the new circular image
    sub_img_arr = numpy.empty(crop_arr.shape ,dtype='uint8')
    sub_img_arr[:,:,:3] = crop_arr[:,:,:3]
    sub_img_arr[:,:,3] = mask*255
    sub_img = Image.fromarray(sub_img_arr, "RGBA").rotate(degree)
    i2 = image.copy()
    i2.paste(sub_img, box[:2], sub_img.convert('RGBA'))
    return i2

i2 = circle_rotate(img, 260, 60, 60, 45)
i2

edited Aug 28, 2016 at 6:52

answered Aug 28, 2016 at 5:37

James

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4 Comments

Bagus Prasetyo W Over a year ago

yes sir, is successfull ,but i can't save a new pict :(

Bagus Prasetyo W Over a year ago

sir why iam not successfull , if i try using circle_rotate

James Over a year ago

You can save the picture using i2.save('./new_image.jpg')

Bagus Prasetyo W Over a year ago

sir iam use SC for rotate, but cant, error in i2 = circle_rotate(img, 260, 60, 60, 45) :( and if i will using SC where code from input image?

Community · Accepted Answer · 2017-05-23 12:30:23Z

0

You can solve this problem as such. Say you have img = Image.open("nime1.png")

Create a copy of the image using img2 = img.copy()
Create a crop of img2 at the desired location using img2.crop(). You can read how to do this here
Paste img2 back onto img at the appropriate location using img.paste()

Notes:

To find the center coordinate, you can divide the width and height by 2 :)

edited May 23, 2017 at 12:30

CommunityBot

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answered Aug 28, 2016 at 5:35

gowrath

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