Fix modified flag behavior

skimage/novice/novice.py

@@ -111,13 +111,9 @@ class Pixel(object):
         NOTE: Using Cartesian coordinate system!
 
         """
-        # skimage dimensions are flipped: y, x
-        self._image[self._picture.height - self._y - 1, self._x] = \
-                (self.red, self.green, self.blue)
-
-        # Modified pictures lose their paths
-        self._picture._picture_path = None
-        self._picture._picture_modified = True
+        row = self._picture.height - self._y - 1
+        self._picture._image[row, self._x] = self.rgb
+        self._picture._image_modified()
 
     def __repr__(self):
         args = self.red, self.green, self.blue
@@ -407,6 +403,10 @@ class Picture(object):
         """True if the picture has changed."""
         return self._modified
 
+    def _image_modified(self):
+        self._modified = True
+        self._path = None
+
     @property
     def format(self):
         """The image format of the picture."""
@@ -427,8 +427,7 @@ class Picture(object):
                 self._image = img_as_ubyte(resize(self._image,
                     (int(value[1]), int(value[0])), order=0))
 
-                self._modified = True
-                self._path = None
+                self._image_modified()
         except TypeError:
             msg = "Expected (width, height), but got {0} instead!"
             raise TypeError(msg.format(value))
@@ -519,6 +518,7 @@ class Picture(object):
                 raise TypeError("Invalid value type")
         else:
             raise TypeError("Invalid key type")
+        self._image_modified()
 
     def __repr__(self):
         args = self.format, self.path, self.modified

skimage/novice/tests/test_novice.py

@@ -1,6 +1,7 @@
 import os
 import tempfile
 
+import numpy as np
 from numpy.testing import assert_equal, assert_raises
 from skimage import novice
 from skimage import data_dir
@@ -50,6 +51,29 @@ def test_modify():
     assert_equal(pic.modified, True)
     assert_equal(pic.path, None)
 
+
+def test_modified_on_set():
+    pic = novice.Picture(SMALL_IMAGE_PATH)
+    pic[0, 0] = (1, 1, 1)
+    assert_equal(pic.modified, True)
+    assert_equal(pic.path, None)
+
+
+def test_modified_on_set_pixel():
+    data = np.zeros(shape=(10, 5, 3), dtype=np.uint8)
+    pic = novice.Picture(image=data)
+
+    pixel = pic[0, 0]
+    pixel.green = 1
+    assert_equal(pic.modified, True)
+
+
+def test_update_on_save():
+    pic = novice.Picture(image=np.zeros((3, 3)))
+    pic.size = (6, 6)
+    assert_equal(pic.modified, True)
+    assert_equal(pic.path, None)
+
     with tempfile.NamedTemporaryFile(suffix=".jpg") as tmp:
         pic.save(tmp.name)