使用 django-resized 调整图像大小

Question

当图像上传到 AWS S3 时，我使用 django-resized 来减小图像的大小。

当图像宽于其高度时，调整大小可以正常工作。但是，当图像高度大于宽度时，输出图像会旋转 90 度，宽度大于高度。

models.py

from django_resized import ResizedImageField

class Catch(models.Model):
    fish_type = models.CharField("Fish Type", max_length=50, choices=fish_choices, default="Carp")
    catch_id = models.AutoField(primary_key=True)
    weight = models.DecimalField("Weight", max_digits=5, decimal_places=2)
    length = models.DecimalField("Length", max_digits=5, decimal_places=2, blank=True, null=True)
    datetime = models.DateTimeField("Catch Time", auto_now=False, auto_now_add=False)
    image = ResizedImageField(size=[1080, 1350], quality=95, null=True, blank=True, default="default_img.png", upload_to="catch_images/")
    fisherman = models.ForeignKey(Fisherman, on_delete=models.CASCADE)
    trip = models.ForeignKey(Trips, on_delete=models.CASCADE)
    hookbait_name = models.CharField('Csali megnevezése', max_length=120, blank=True, null=True)
    hookbait = models.ForeignKey(HookBait, on_delete=models.SET_NULL, blank=True, null=True)

settings.py

DJANGORESIZED_DEFAULT_KEEP_META = True
DJANGORESIZED_DEFAULT_FORCE_FORMAT = 'JPEG'
DJANGORESIZED_DEFAULT_FORMAT_EXTENSIONS = {'JPEG': ".jpg"}
DJANGORESIZED_DEFAULT_NORMALIZE_ROTATION = True

我只想在保持纵横比的同时缩小图像的大小。

提前感谢您的帮助。

编辑！

我设法自己解决了这个问题。我使用枕头来调整图像大小，但我还必须根据方向标签旋转它们。

正确的代码在这里：

models.py

from PIL import Image, ExifTags
from io import BytesIO
from django.core.files import File

class Catch(models.Model):
    fish_type = models.CharField("Fish Type", max_length=50, choices=fish_choices, default="Carp")
    catch_id = models.AutoField(primary_key=True)
    weight = models.DecimalField("Weight", max_digits=5, decimal_places=2)
    length = models.DecimalField("Length", max_digits=5, decimal_places=2, blank=True, null=True)
    datetime = models.DateTimeField("Catch Time", auto_now=False, auto_now_add=False)
    image = models.ImageField(null=True, blank=True, default="default_img.png", upload_to="catch_images/")
    fisherman = models.ForeignKey(Fisherman, on_delete=models.CASCADE)
    trip = models.ForeignKey(Trips, on_delete=models.CASCADE)
    hookbait_name = models.CharField('Csali megnevezése', max_length=120, blank=True, null=True)
    hookbait = models.ForeignKey(HookBait, on_delete=models.SET_NULL, blank=True, null=True)

    class Meta:
        verbose_name = "Catch"
        verbose_name_plural = "Catches"
    
    def save(self, *args, **kwargs):
        if self.image:
            img = Image.open(BytesIO(self.image.read()))
            
            if hasattr(img, '_getexif'):
                exif = img._getexif()
                if exif:
                    for tag, label in ExifTags.TAGS.items():
                        if label == 'Orientation':
                            orientation = tag
                            break
                    if orientation in exif:
                        if exif[orientation] == 3:
                            img = img.rotate(180, expand=True)
                        elif exif[orientation] == 6:
                            img = img.rotate(270, expand=True)
                        elif exif[orientation] == 8:
                            img = img.rotate(90, expand=True)

            img.thumbnail((1080,1080), Image.ANTIALIAS)
            output = BytesIO()
            img.save(output, format='JPEG', quality=95)
            output.seek(0)
            self.image = File(output, self.image.name) 

        return super().save(*args, **kwargs)

Answer 1

您应该为此使用 PIL/pillow。像这样编辑您的模型，所有图像将在保存到数据库之前调整大小。

你可以这样做：

from PIL import Image as Img
import io
from django.core.files.uploadhandler import InMemoryUploadedFile

class Catch(models.Model):
   #rest fields here
   image=models.ImageField(upload_to='Media/Users')

   def save(self):
      if self.image:
          img = Img.open(io.BytesIO(self.image.read()))
          if img.mode != 'RGB':
              img = img.convert('RGB')
          img.thumbnail((100,100), Img.ANTIALIAS)  #(width,height)
          output = io.BytesIO()
          img.save(output, format='JPEG')
          output.seek(0)
          self.image= InMemoryUploadedFile(output,'ImageField', "%s.jpg" 
                      %self.image.name.split('.')[0], 'image/jpeg',"Content- 
                      Type: charset=utf-8", None)
      super(Catch, self).save()

注意：thumbnail 函数还可以减小图像的大小。在这里，我为输出图像指定了宽度和高度 100px。只需根据您的要求更改元组值(width,height)

另外，如果您只想调整图像大小，可以使用resize 函数而不是thumbnail。