From e3f8679862e3ada2552fe4cfc3a77b63acbe1997 Mon Sep 17 00:00:00 2001
From: Karl Hobley <karl@torchbox.com>
Date: Thu, 17 Jul 2014 12:54:09 +0100
Subject: [PATCH] Refactored crop_to_centre actions to use a utils method

---
 wagtail/wagtailimages/backends/pillow.py | 21 +++++---------
 wagtail/wagtailimages/backends/wand.py   | 28 ++++++++-----------
 wagtail/wagtailimages/utils/crop.py      | 35 ++++++++++++++++++++++++
 3 files changed, 53 insertions(+), 31 deletions(-)
 create mode 100644 wagtail/wagtailimages/utils/crop.py

diff --git a/wagtail/wagtailimages/backends/pillow.py b/wagtail/wagtailimages/backends/pillow.py
index 96976c277f..337399fe69 100644
--- a/wagtail/wagtailimages/backends/pillow.py
+++ b/wagtail/wagtailimages/backends/pillow.py
@@ -1,8 +1,10 @@
 from __future__ import absolute_import
 
-from .base import BaseImageBackend
 import PIL.Image
 
+from wagtail.wagtailimages.backends.base import BaseImageBackend
+from wagtail.wagtailimages.utils.crop import crop_to_centre
+
 
 class PillowBackend(BaseImageBackend):
     def __init__(self, params):
@@ -21,18 +23,9 @@ class PillowBackend(BaseImageBackend):
         return image.resize(size, PIL.Image.ANTIALIAS)
 
     def crop_to_centre(self, image, size):
-        (original_width, original_height) = image.size
-        (target_width, target_height) = size
+        crop_box = crop_to_centre(image.size, size)
 
-        # final dimensions should not exceed original dimensions
-        final_width = min(original_width, target_width)
-        final_height = min(original_height, target_height)
-
-        if final_width == original_width and final_height == original_height:
+        if crop_box.size != image.size:
+            return image.crop(crop_box)
+        else:
             return image
-
-        left = (original_width - final_width) / 2
-        top = (original_height - final_height) / 2
-        return image.crop(
-            (left, top, left + final_width, top + final_height)
-        )
diff --git a/wagtail/wagtailimages/backends/wand.py b/wagtail/wagtailimages/backends/wand.py
index 91f2d255a7..cde7db50e6 100644
--- a/wagtail/wagtailimages/backends/wand.py
+++ b/wagtail/wagtailimages/backends/wand.py
@@ -1,9 +1,11 @@
 from __future__ import absolute_import
 
-from .base import BaseImageBackend
 from wand.image import Image
 from wand.api import library
 
+from wagtail.wagtailimages.backends.base import BaseImageBackend
+from wagtail.wagtailimages.utils.crop import crop_to_centre
+
 
 class WandBackend(BaseImageBackend):
     def __init__(self, params):
@@ -25,21 +27,13 @@ class WandBackend(BaseImageBackend):
         return new_image
 
     def crop_to_centre(self, image, size):
-        (original_width, original_height) = image.size
-        (target_width, target_height) = size
+        crop_box = crop_to_centre(image.size, size)
 
-        # final dimensions should not exceed original dimensions
-        final_width = min(original_width, target_width)
-        final_height = min(original_height, target_height)
-
-        if final_width == original_width and final_height == original_height:
+        if crop_box.size != image.size:
+            new_image = image.clone()
+            new_image.crop(
+                left=crop_box[0], top=crop_box[1], right=crop_box[2], bottom=crop_box[3]
+            )
+            return new_image
+        else:
             return image
-
-        left = (original_width - final_width) / 2
-        top = (original_height - final_height) / 2
-
-        new_image = image.clone()
-        new_image.crop(
-            left=left, top=top, right=left + final_width, bottom=top + final_height
-        )
-        return new_image
diff --git a/wagtail/wagtailimages/utils/crop.py b/wagtail/wagtailimages/utils/crop.py
new file mode 100644
index 0000000000..c45c158424
--- /dev/null
+++ b/wagtail/wagtailimages/utils/crop.py
@@ -0,0 +1,35 @@
+class CropBox(object):
+    def __init__(self, left, top, right, bottom):
+        self.left = int(left)
+        self.top = int(top)
+        self.right = int(right)
+        self.bottom = int(bottom)
+
+    def __getitem__(self, key):
+        return (self.left, self.top, self.right, self.bottom)[key]
+
+    @property
+    def width(self):
+        return self.right - self.left
+
+    @property
+    def height(self):
+        return self.bottom - self.top
+
+    @property
+    def size(self):
+        return self.width, self.height
+
+
+def crop_to_centre(image_size, crop_size):
+    (original_width, original_height) = image_size
+    (crop_width, crop_height) = crop_size
+
+    # final dimensions should not exceed original dimensions
+    final_width = min(original_width, crop_width)
+    final_height = min(original_height, crop_height)
+
+    left = (original_width - final_width) / 2
+    top = (original_height - final_height) / 2
+
+    return CropBox(left, top, left + final_width, top + final_height)