process() accepts file

In the old IK API, processors (like `Transpose`) were able to access
the file by inspecting the model instance (which carried an options
object that specified the attribute name of the ImageField from which
the file could be extracted). Since the new API allows for multiple
ImageFields (and because IKOptions have been removed), it became
necessary to provide more information. Initially, this was accomplished
by passing the spec to `process()`, however with the addition of
ProcessedImageField, it became clear the a cleaner solution was to pass
only the field file (ImageSpecFile or ProcessedImageFieldFile).

This keeps the ORM stuff (fields, etc.) out of the `ImageProcessor` API
but (because field files, not just regular files, are passed) the
average hacker can still have their processor make use of model
information by accessing the model through the file's `instance`
property.

imagekit/fields.py

@@ -24,11 +24,11 @@ def __init__(self, processors=None, quality=70, format=None):
         self.quality = quality
         self.format = format
 
-    def process(self, image, obj):
+    def process(self, image, file):
         fmt = image.format
         img = image.copy()
         for proc in self.processors:
-            img, fmt = proc.process(img, fmt, obj, self)
+            img, fmt = proc.process(img, fmt, file)
         format = self.format or fmt
         img.format = format
         return img, format
@@ -161,7 +161,7 @@ def _create(self):
                 return
             fp.seek(0)
             fp = StringIO(fp.read())
-            self._img, self._fmt = self._spec.process(Image.open(fp), self._obj)
+            self._img, self._fmt = self._spec.process(Image.open(fp), self)
             # save the new image to the cache
             content = ContentFile(self._get_imgfile().read())
             self.storage.save(self.name, content)
@@ -270,7 +270,7 @@ def _post_save_handler(sender, instance=None, created=False, raw=False, **kwargs
         if imgfield:
             newfile = imgfield.storage.open(imgfield.name)
             img = Image.open(newfile)
-            img, format = spec_file._spec.process(img, instance)
+            img, format = spec_file._spec.process(img, spec_file)
             if format != 'JPEG':
                 imgfile = img_to_fobj(img, format)
             else:
@@ -347,7 +347,7 @@ class ProcessedImageFieldFile(ImageFieldFile):
     def save(self, name, content, save=True):
         new_filename = self.field.generate_filename(self.instance, name)
         img = Image.open(content)
-        img, format = self.field.process(img, self.instance)
+        img, format = self.field.process(img, self)
         format = self._get_format(new_filename, format)
         if format != 'JPEG':
             imgfile = img_to_fobj(img, format)

imagekit/processors.py

@@ -11,7 +11,7 @@ class method named "process" which processes the supplied image using
 class ImageProcessor(object):
     """ Base image processor class """
 
-    def process(self, img, fmt, obj, spec):
+    def process(self, img, fmt, file):
         return img, fmt
 
 
@@ -23,7 +23,7 @@ def __init__(self, color=1.0, brightness=1.0, contrast=1.0, sharpness=1.0):
         self.contrast = contrast
         self.sharpness = sharpness
 
-    def process(self, img, fmt, obj, spec):
+    def process(self, img, fmt, file):
         img = img.convert('RGB')
         for name in ['Color', 'Brightness', 'Contrast', 'Sharpness']:
             factor = getattr(self, name.lower())
@@ -40,7 +40,7 @@ class Reflection(ImageProcessor):
     size = 0.0
     opacity = 0.6
 
-    def process(self, img, fmt, obj, spec):
+    def process(self, img, fmt, file):
         # convert bgcolor string to rgb value
         background_color = ImageColor.getrgb(self.background_color)
         # handle palleted images
@@ -88,7 +88,7 @@ def __init__(self, width=None, height=None):
         if height is not None:
             self.height = height
 
-    def process(self, img, fmt, obj, spec):
+    def process(self, img, fmt, file):
         raise NotImplementedError('process must be overridden by subclasses.')
 
 
@@ -120,7 +120,7 @@ def __init__(self, width=None, height=None, anchor=None):
         super(Crop, self).__init__(width, height)
         self.anchor = anchor
 
-    def process(self, img, fmt, obj, spec):
+    def process(self, img, fmt, file):
         cur_width, cur_height = img.size
         horizontal_anchor, vertical_anchor = Crop._ANCHOR_PTS[self.anchor or \
                 Crop.CENTER]
@@ -148,7 +148,7 @@ def __init__(self, width=None, height=None, upscale=None):
         super(Fit, self).__init__(width, height)
         self.upscale = upscale
 
-    def process(self, img, fmt, obj, spec):
+    def process(self, img, fmt, file):
         cur_width, cur_height = img.size
         if not self.width is None and not self.height is None:
             ratio = min(float(self.width)/cur_width,
@@ -196,10 +196,10 @@ class Transpose(ImageProcessor):
 
     method = 'auto'
 
-    def process(self, img, fmt, obj, spec):
+    def process(self, img, fmt, file):
         if self.method == 'auto':
             try:
-                orientation = Image.open(spec._get_imgfield(obj).file)._getexif()[0x0112]
+                orientation = Image.open(file.file)._getexif()[0x0112]
                 ops = self.EXIF_ORIENTATION_STEPS[orientation]
             except:
                 ops = []