我试图为幻灯片视频调整一些图像的大小，因此，我想要的不仅仅是一个最大维度，而是一个最大宽度和最大高度(视频帧的大小)。 而且总有可能拍一个人像视频…… 图像。缩略图方法是有前途的，但我不能使它放大一个较小的图像。

所以当我在这里(或其他地方)找不到明显的方法时，我写了这个函数，并把它放在这里:

from PIL import Image

def get_resized_img(img_path, video_size):
    img = Image.open(img_path)
    width, height = video_size  # these are the MAX dimensions
    video_ratio = width / height
    img_ratio = img.size[0] / img.size[1]
    if video_ratio >= 1:  # the video is wide
        if img_ratio <= video_ratio:  # image is not wide enough
            width_new = int(height * img_ratio)
            size_new = width_new, height
        else:  # image is wider than video
            height_new = int(width / img_ratio)
            size_new = width, height_new
    else:  # the video is tall
        if img_ratio >= video_ratio:  # image is not tall enough
            height_new = int(width / img_ratio)
            size_new = width, height_new
        else:  # image is taller than video
            width_new = int(height * img_ratio)
            size_new = width_new, height
    return img.resize(size_new, resample=Image.LANCZOS)

from PIL import Image
from resizeimage import resizeimage

def resize_file(in_file, out_file, size):
    with open(in_file) as fd:
        image = resizeimage.resize_thumbnail(Image.open(fd), size)
    image.save(out_file)
    image.close()

resize_file('foo.tif', 'foo_small.jpg', (256, 256))

我使用这个库:

pip install python-resize-image

一个简单的方法，保持约束比率和通过最大宽度/高度。不是最漂亮的，但可以完成工作，而且很容易理解:

def resize(img_path, max_px_size, output_folder):
    with Image.open(img_path) as img:
        width_0, height_0 = img.size
        out_f_name = os.path.split(img_path)[-1]
        out_f_path = os.path.join(output_folder, out_f_name)

        if max((width_0, height_0)) <= max_px_size:
            print('writing {} to disk (no change from original)'.format(out_f_path))
            img.save(out_f_path)
            return

        if width_0 > height_0:
            wpercent = max_px_size / float(width_0)
            hsize = int(float(height_0) * float(wpercent))
            img = img.resize((max_px_size, hsize), Image.ANTIALIAS)
            print('writing {} to disk'.format(out_f_path))
            img.save(out_f_path)
            return

        if width_0 < height_0:
            hpercent = max_px_size / float(height_0)
            wsize = int(float(width_0) * float(hpercent))
            img = img.resize((max_px_size, wsize), Image.ANTIALIAS)
            print('writing {} to disk'.format(out_f_path))
            img.save(out_f_path)
            return

下面是一个python脚本，使用这个函数来运行批量图像调整。

要使新图像的宽度和高度是原图像的一半，请使用以下代码:

  from PIL import Image
  im = Image.open("image.jpg")
  resized_im = im.resize((round(im.size[0]*0.5), round(im.size[1]*0.5)))
    
  #Save the cropped image
  resized_im.save('resizedimage.jpg')

调整:用定额调整固定宽度:

from PIL import Image
new_width = 300
im = Image.open("img/7.jpeg")
concat = int(new_width/float(im.size[0]))
size = int((float(im.size[1])*float(concat)))
resized_im = im.resize((new_width,size), Image.ANTIALIAS)
#Save the cropped image
resized_im.save('resizedimage.jpg')

这个脚本将使用PIL (Python成像库)将图像(somepic.jpg)调整为300像素的宽度和与新宽度成比例的高度。它通过确定300像素是原始宽度(img.size[0])的百分比，然后将原始高度(img.size[1])乘以该百分比来实现这一点。将“basewidth”更改为任何其他数字以更改图像的默认宽度。

from PIL import Image

basewidth = 300
img = Image.open('somepic.jpg')
wpercent = (basewidth/float(img.size[0]))
hsize = int((float(img.size[1])*float(wpercent)))
img = img.resize((basewidth,hsize), Image.Resampling.LANCZOS)
img.save('somepic.jpg')

我试图为幻灯片视频调整一些图像的大小，因此，我想要的不仅仅是一个最大维度，而是一个最大宽度和最大高度(视频帧的大小)。 而且总有可能拍一个人像视频…… 图像。缩略图方法是有前途的，但我不能使它放大一个较小的图像。

所以当我在这里(或其他地方)找不到明显的方法时，我写了这个函数，并把它放在这里:

from PIL import Image

def get_resized_img(img_path, video_size):
    img = Image.open(img_path)
    width, height = video_size  # these are the MAX dimensions
    video_ratio = width / height
    img_ratio = img.size[0] / img.size[1]
    if video_ratio >= 1:  # the video is wide
        if img_ratio <= video_ratio:  # image is not wide enough
            width_new = int(height * img_ratio)
            size_new = width_new, height
        else:  # image is wider than video
            height_new = int(width / img_ratio)
            size_new = width, height_new
    else:  # the video is tall
        if img_ratio >= video_ratio:  # image is not tall enough
            height_new = int(width / img_ratio)
            size_new = width, height_new
        else:  # image is taller than video
            width_new = int(height * img_ratio)
            size_new = width_new, height
    return img.resize(size_new, resample=Image.LANCZOS)