Add access functions for ImagingEffectSpread with a test

PIL/Image.py

@@ -1910,6 +1910,16 @@ class Image:
         im = self.im.transpose(method)
         return self._new(im)
 
+    def effect_spread(self, distance):
+        """
+        Randomly spread pixels in an image.
+
+        :param distance: Distance to spread pixels.
+        """
+        self.load()
+        im = self.im.effect_spread(distance)
+        return self._new(im)
+
 
 # --------------------------------------------------------------------
 # Lazy operations
@@ -2436,6 +2446,7 @@ def effect_mandelbrot(size, extent, quality):
     """
     return Image()._new(core.effect_mandelbrot(size, extent, quality))
 
+
 def effect_noise(size, sigma):
     """
     Generate Gaussian noise centered around 128.

Tests/test_image.py

@@ -152,7 +152,7 @@ class TestImage(PillowTestCase):
 
         # Assert
         self.assertEqual(im.size, (512, 512))
-        im2 = Image.open('Tests/images/mandelbrot.png')
+        im2 = Image.open('Tests/images/effect_mandelbrot.png')
         self.assert_image_equal(im, im2)
 
     @unittest.skipUnless(sys.platform.startswith('win32'),
@@ -170,6 +170,19 @@ class TestImage(PillowTestCase):
         self.assertEqual(im.getpixel((0, 0)), 60)
         self.assertEqual(im.getpixel((0, 1)), 28)
 
+    def test_effect_spread(self):
+        # Arrange
+        im = lena()
+        distance = 10
+
+        # Act
+        im2 = im.effect_spread(distance)
+
+        # Assert
+        self.assertEqual(im.size, (128, 128))
+        im3 = Image.open('Tests/images/effect_spread.png')
+        self.assert_image_equal(im2, im3)
+
 if __name__ == '__main__':
     unittest.main()
 

libImaging/Effects.c

@@ -124,11 +124,11 @@ ImagingEffectSpread(Imaging imIn, int distance)
     imOut = ImagingNew(imIn->mode, imIn->xsize, imIn->ysize);
 
     if (!imOut)
-	return NULL;
+    return NULL;
 
-#define	SPREAD(type, image)\
+#define SPREAD(type, image)\
     for (y = 0; y < imIn->ysize; y++)\
-	for (x = 0; x < imIn->xsize; x++) {\
+    for (x = 0; x < imIn->xsize; x++) {\
             int xx = x + (rand() % distance) - distance/2;\
             int yy = y + (rand() % distance) - distance/2;\
             if (xx >= 0 && xx < imIn->xsize && yy >= 0 && yy < imIn->ysize) {\
@@ -139,9 +139,9 @@ ImagingEffectSpread(Imaging imIn, int distance)
         }
 
     if (imIn->image8) {
-	SPREAD(UINT8, image8);
+    SPREAD(UINT8, image8);
     } else {
-	SPREAD(INT32, image32);
+    SPREAD(INT32, image32);
     }
 
     ImagingCopyInfo(imOut, imIn);