From 295382aadc994dc81e5076450dce5cf573a9bbd0 Mon Sep 17 00:00:00 2001
From: homm <homm86@gmail.com>
Date: Fri, 2 Dec 2016 15:40:32 +0300
Subject: [PATCH] vertical and horizontal pass with boxes

---
 PIL/Image.py                 | 13 +++++++-----
 Tests/test_image_resample.py | 40 ++++++++++++++++++++++++++++--------
 2 files changed, 39 insertions(+), 14 deletions(-)

diff --git a/PIL/Image.py b/PIL/Image.py
index 844f27ab5..a3171aeaa 100644
--- a/PIL/Image.py
+++ b/PIL/Image.py
@@ -1544,10 +1544,14 @@ class Image(object):
         ):
             raise ValueError("unknown resampling filter")
 
-        self.load()
-
         size = tuple(size)
-        if self.size == size:
+
+        if box is None:
+            box = (0, 0) + self.size
+        else:
+            box = tuple(box)
+
+        if self.size == size and box == (0, 0) + self.size:
             return self.copy()
 
         if self.mode in ("1", "P"):
@@ -1559,8 +1563,7 @@ class Image(object):
         if self.mode == 'RGBA':
             return self.convert('RGBa').resize(size, resample).convert('RGBA')
 
-        if box is None:
-            box = (0, 0) + self.size
+        self.load()
 
         return self._new(self.im.resize(size, resample, box))
 
diff --git a/Tests/test_image_resample.py b/Tests/test_image_resample.py
index a3e507745..632ead76c 100644
--- a/Tests/test_image_resample.py
+++ b/Tests/test_image_resample.py
@@ -1,5 +1,7 @@
 from __future__ import division
 
+from contextlib import contextmanager
+
 from helper import unittest, PillowTestCase, hopper
 from PIL import Image, ImageDraw, ImageMode
 
@@ -303,24 +305,44 @@ class CoreResampleAlphaCorrectTest(PillowTestCase):
 
 
 class CoreResamplePassesTest(PillowTestCase):
+    @contextmanager
+    def count(self, diff):
+        count = Image.core.getcount() + diff
+        yield
+        self.assertEqual(Image.core.getcount(), count)
+
     def test_horizontal(self):
         im = hopper('L')
-        count = Image.core.getcount()
-        im.resize((im.size[0] + 10, im.size[1]), Image.BILINEAR)
-        self.assertEqual(Image.core.getcount(), count + 1)
+        with self.count(1):
+            im.resize((im.size[0] - 10, im.size[1]), Image.BILINEAR)
 
     def test_vertical(self):
         im = hopper('L')
-        count = Image.core.getcount()
-        im.resize((im.size[0], im.size[1] + 10), Image.BILINEAR)
-        self.assertEqual(Image.core.getcount(), count + 1)
+        with self.count(1):
+            im.resize((im.size[0], im.size[1] - 10), Image.BILINEAR)
 
     def test_both(self):
         im = hopper('L')
-        count = Image.core.getcount()
-        im.resize((im.size[0] + 10, im.size[1] + 10), Image.BILINEAR)
-        self.assertEqual(Image.core.getcount(), count + 2)
+        with self.count(2):
+            im.resize((im.size[0] - 10, im.size[1] - 10), Image.BILINEAR)
 
+    def test_box_horizontal(self):
+        im = hopper('L')
+        box = (20, 0, im.size[0] - 20, im.size[1])
+        with self.count(1):
+            # the same size, but different box
+            with_box = im.resize(im.size, Image.BILINEAR, box)
+        cropped = im.crop(box).resize(im.size, Image.BILINEAR)
+        self.assert_image_similar(with_box, cropped, 0.1)
+
+    def test_box_vertical(self):
+        im = hopper('L')
+        box = (0, 20, im.size[0], im.size[1] - 20)
+        with self.count(1):
+            # the same size, but different box
+            with_box = im.resize(im.size, Image.BILINEAR, box)
+        cropped = im.crop(box).resize(im.size, Image.BILINEAR)
+        self.assert_image_similar(with_box, cropped, 0.1)
 
 class CoreResampleCoefficientsTest(PillowTestCase):
     def test_reduce(self):