From 4e23254e73d2d921116f6b7ad399a2c905a0f0cf Mon Sep 17 00:00:00 2001
From: Matthew Tretter <matthew@exanimo.com>
Date: Wed, 21 Sep 2011 19:02:18 -0400
Subject: [PATCH] Crop processor accepts anchor argument.

---
 imagekit/models.py     | 14 -------------
 imagekit/options.py    |  2 --
 imagekit/processors.py | 46 ++++++++++++++++++++++++++++++++----------
 3 files changed, 35 insertions(+), 27 deletions(-)

diff --git a/imagekit/models.py b/imagekit/models.py
index 8e22975..b9ace46 100644
--- a/imagekit/models.py
+++ b/imagekit/models.py
@@ -16,20 +16,6 @@ from imagekit.utils import img_to_fobj
 # Modify image file buffer size.
 ImageFile.MAXBLOCK = getattr(settings, 'PIL_IMAGEFILE_MAXBLOCK', 256 * 2 ** 10)
 
-# Choice tuples for specifying the crop origin.
-# These are provided for convenience.
-CROP_HORZ_CHOICES = (
-    (0, _('left')),
-    (1, _('center')),
-    (2, _('right')),
-)
-
-CROP_VERT_CHOICES = (
-    (0, _('top')),
-    (1, _('center')),
-    (2, _('bottom')),
-)
-
 
 class ImageModelBase(ModelBase):
     """ ImageModel metaclass
diff --git a/imagekit/options.py b/imagekit/options.py
index f23683e..833dd23 100644
--- a/imagekit/options.py
+++ b/imagekit/options.py
@@ -35,8 +35,6 @@ class Options(object):
         new_name = '{0}_{1}.{2}'.format(filename, specname, extension)
         return os.path.join(os.path.join('cache', filepath), new_name)
 
-    crop_horz_field = 'crop_horz'
-    crop_vert_field = 'crop_vert'
     preprocessor_spec = None
     save_count_as = None
     specs = None
diff --git a/imagekit/processors.py b/imagekit/processors.py
index a4ae9a0..ea75b31 100644
--- a/imagekit/processors.py
+++ b/imagekit/processors.py
@@ -93,27 +93,51 @@ class _Resize(ImageProcessor):
 
 
 class Crop(_Resize):
-    def __init__(self, width=None, height=None):
+
+    TOP_LEFT = 'tl'
+    TOP = 't'
+    TOP_RIGHT = 'tr'
+    BOTTOM_LEFT = 'bl'
+    BOTTOM = 'b'
+    BOTTOM_RIGHT = 'br'
+    CENTER = 'c'
+    LEFT = 'l'
+    RIGHT = 'r'
+
+    _ANCHOR_PTS = {
+        TOP_LEFT: (0, 0),
+        TOP: (0.5, 0),
+        TOP_RIGHT: (1, 0),
+        LEFT: (0, 0.5),
+        CENTER: (0.5, 0.5),
+        RIGHT: (1, 0.5),
+        BOTTOM_LEFT: (0, 1),
+        BOTTOM: (0.5, 1),
+        BOTTOM_RIGHT: (1, 1),
+    }
+
+    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):
         cur_width, cur_height = img.size
-        crop_horz = getattr(obj, obj._ik.crop_horz_field, 1)
-        crop_vert = getattr(obj, obj._ik.crop_vert_field, 1)
+        horizontal_anchor, vertical_anchor = Crop._ANCHOR_PTS[self.anchor or \
+                Crop.CENTER]
         ratio = max(float(self.width)/cur_width, float(self.height)/cur_height)
         resize_x, resize_y = ((cur_width * ratio), (cur_height * ratio))
         crop_x, crop_y = (abs(self.width - resize_x), abs(self.height - resize_y))
         x_diff, y_diff = (int(crop_x / 2), int(crop_y / 2))
         box_left, box_right = {
-            0: (0, self.width),
-            1: (int(x_diff), int(x_diff + self.width)),
-            2: (int(crop_x), int(resize_x)),
-        }[crop_horz]
+            0:   (0, self.width),
+            0.5: (int(x_diff), int(x_diff + self.width)),
+            1:   (int(crop_x), int(resize_x)),
+        }[horizontal_anchor]
         box_upper, box_lower = {
-            0: (0, self.height),
-            1: (int(y_diff), int(y_diff + self.height)),
-            2: (int(crop_y), int(resize_y)),
-        }[crop_vert]
+            0:   (0, self.height),
+            0.5: (int(y_diff), int(y_diff + self.height)),
+            1:   (int(crop_y), int(resize_y)),
+        }[vertical_anchor]
         box = (box_left, box_upper, box_right, box_lower)
         img = img.resize((int(resize_x), int(resize_y)), Image.ANTIALIAS).crop(box)
         return img, fmt