Added three new channel operations

Tests/test_imagechops.py

@@ -38,6 +38,10 @@ def test_sanity():
     ImageChops.blend(im, im, 0.5)
     ImageChops.composite(im, im, im)
 
+    ImageChops.soft_light(im, im)
+    ImageChops.hard_light(im, im)
+    ImageChops.overlay(im, im)
+
     ImageChops.offset(im, 10)
     ImageChops.offset(im, 10, 20)
 
@@ -209,8 +213,8 @@ def test_lighter_image():
             # Act
             new = ImageChops.lighter(im1, im2)
 
-    # Assert
-    assert_image_equal(new, im1)
+        # Assert
+        assert_image_equal(new, im1)
 
 
 def test_lighter_pixel():
@@ -275,13 +279,13 @@ def test_offset():
         # Act
         new = ImageChops.offset(im, xoffset, yoffset)
 
-    # Assert
-    assert new.getbbox() == (0, 45, 100, 96)
-    assert new.getpixel((50, 50)) == BLACK
-    assert new.getpixel((50 + xoffset, 50 + yoffset)) == DARK_GREEN
+        # Assert
+        assert new.getbbox() == (0, 45, 100, 96)
+        assert new.getpixel((50, 50)) == BLACK
+        assert new.getpixel((50 + xoffset, 50 + yoffset)) == DARK_GREEN
 
-    # Test no yoffset
-    assert ImageChops.offset(im, xoffset) == ImageChops.offset(im, xoffset, xoffset)
+        # Test no yoffset
+        assert ImageChops.offset(im, xoffset) == ImageChops.offset(im, xoffset, xoffset)
 
 
 def test_screen():
@@ -362,6 +366,45 @@ def test_subtract_modulo_no_clip():
     assert new.getpixel((50, 50)) == (241, 167, 127)
 
 
+def test_soft_light():
+    # Arrange
+    im1 = Image.open("Tests/images/hopper.png")
+    im2 = Image.open("Tests/images/hopper-XYZ.png")
+
+    # Act
+    new = ImageChops.soft_light(im1, im2)
+
+    # Assert
+    assert new.getpixel((64, 64)) == (163, 54, 32)
+    assert new.getpixel((15, 100)) == (1, 1, 3)
+
+
+def test_hard_light():
+    # Arrange
+    im1 = Image.open("Tests/images/hopper.png")
+    im2 = Image.open("Tests/images/hopper-XYZ.png")
+
+    # Act
+    new = ImageChops.hard_light(im1, im2)
+
+    # Assert
+    assert new.getpixel((64, 64)) == (144, 50, 27)
+    assert new.getpixel((15, 100)) == (1, 1, 2)
+
+
+def test_overlay():
+    # Arrange
+    im1 = Image.open("Tests/images/hopper.png")
+    im2 = Image.open("Tests/images/hopper-XYZ.png")
+
+    # Act
+    new = ImageChops.overlay(im1, im2)
+
+    # Assert
+    assert new.getpixel((64, 64)) == (159, 50, 27)
+    assert new.getpixel((15, 100)) == (1, 1, 2)
+
+
 def test_logical():
     def table(op, a, b):
         out = []

docs/reference/ImageChops.rst

@@ -36,6 +36,9 @@ operations in this module).
 .. autofunction:: PIL.ImageChops.logical_or
 .. autofunction:: PIL.ImageChops.logical_xor
 .. autofunction:: PIL.ImageChops.multiply
+.. autofunction:: PIL.ImageChops.soft_light
+.. autofunction:: PIL.ImageChops.hard_light
+.. autofunction:: PIL.ImageChops.overlay
 .. py:method:: PIL.ImageChops.offset(image, xoffset, yoffset=None)
 
     Returns a copy of the image where data has been offset by the given

src/PIL/ImageChops.py

@@ -139,6 +139,42 @@ def screen(image1, image2):
     return image1._new(image1.im.chop_screen(image2.im))
 
 
+def soft_light(image1, image2):
+    """
+    Superimposes two images on top of each other using the Soft Light algorithm
+
+    :rtype: :py:class:`~PIL.Image.Image`
+    """
+
+    image1.load()
+    image2.load()
+    return image1._new(image1.im.chop_soft_light(image2.im))
+
+
+def hard_light(image1, image2):
+    """
+    Superimposes two images on top of each other using the Hard Light algorithm
+
+    :rtype: :py:class:`~PIL.Image.Image`
+    """
+
+    image1.load()
+    image2.load()
+    return image1._new(image1.im.chop_hard_light(image2.im))
+
+
+def overlay(image1, image2):
+    """
+    Superimposes two images on top of each other using the Overlay algorithm
+
+    :rtype: :py:class:`~PIL.Image.Image`
+    """
+
+    image1.load()
+    image2.load()
+    return image1._new(image1.im.chop_overlay(image2.im))
+
+
 def add(image1, image2, scale=1.0, offset=0):
     """
     Adds two images, dividing the result by scale and adding the

src/_imaging.c

@@ -2406,6 +2406,38 @@ _chop_subtract_modulo(ImagingObject* self, PyObject* args)
     return PyImagingNew(ImagingChopSubtractModulo(self->image, imagep->image));
 }
 
+static PyObject*
+_chop_soft_light(ImagingObject* self, PyObject* args)
+{
+    ImagingObject* imagep;
+
+    if (!PyArg_ParseTuple(args, "O!", &Imaging_Type, &imagep))
+        return NULL;
+
+    return PyImagingNew(ImagingChopSoftLight(self->image, imagep->image));
+}
+
+static PyObject*
+_chop_hard_light(ImagingObject* self, PyObject* args)
+{
+    ImagingObject* imagep;
+
+    if (!PyArg_ParseTuple(args, "O!", &Imaging_Type, &imagep))
+        return NULL;
+
+    return PyImagingNew(ImagingChopHardLight(self->image, imagep->image));
+}
+
+static PyObject*
+_chop_overlay(ImagingObject* self, PyObject* args)
+{
+    ImagingObject* imagep;
+
+    if (!PyArg_ParseTuple(args, "O!", &Imaging_Type, &imagep))
+        return NULL;
+
+    return PyImagingNew(ImagingOverlay(self->image, imagep->image));
+}
 #endif
 
 
@@ -3325,6 +3357,10 @@ static struct PyMethodDef methods[] = {
     {"chop_and", (PyCFunction)_chop_and, 1},
     {"chop_or", (PyCFunction)_chop_or, 1},
     {"chop_xor", (PyCFunction)_chop_xor, 1},
+    {"chop_soft_light", (PyCFunction)_chop_soft_light, 1},
+    {"chop_hard_light", (PyCFunction)_chop_hard_light, 1},
+    {"chop_overlay", (PyCFunction)_chop_overlay, 1},
+
 #endif
 
 #ifdef WITH_UNSHARPMASK

src/libImaging/Chops.c

@@ -146,3 +146,27 @@ ImagingChopSubtractModulo(Imaging imIn1, Imaging imIn2)
 {
     CHOP2(in1[x] - in2[x], NULL);
 }
+
+Imaging
+ImagingChopSoftLight(Imaging imIn1, Imaging imIn2)
+{
+    CHOP2( (((255-in1[x]) * (in1[x]*in2[x]) ) / 65536) +
+         (in1[x] * ( 255 - ( (255 - in1[x]) * (255 - in2[x] ) / 255) )) / 255
+         , NULL );
+}
+
+Imaging
+ImagingChopHardLight(Imaging imIn1, Imaging imIn2)
+{
+    CHOP2( (in2[x]<128) ? ( (in1[x]*in2[x])/127)
+                        : 255 - ( ((255-in2[x]) * (255-in1[x])) / 127)
+         , NULL);
+}
+
+Imaging
+ImagingOverlay(Imaging imIn1, Imaging imIn2)
+{
+    CHOP2( (in1[x]<128) ? ( (in1[x]*in2[x])/127)
+                        : 255 - ( ((255-in1[x]) * (255-in2[x])) / 127)
+         , NULL);
+}

src/libImaging/Imaging.h

@@ -339,6 +339,9 @@ extern Imaging ImagingChopSubtract(
     Imaging imIn1, Imaging imIn2, float scale, int offset);
 extern Imaging ImagingChopAddModulo(Imaging imIn1, Imaging imIn2);
 extern Imaging ImagingChopSubtractModulo(Imaging imIn1, Imaging imIn2);
+extern Imaging ImagingChopSoftLight(Imaging imIn1, Imaging imIn2);
+extern Imaging ImagingChopHardLight(Imaging imIn1, Imaging imIn2);
+extern Imaging ImagingOverlay(Imaging imIn1, Imaging imIn2);
 
 /* "1" images only */
 extern Imaging ImagingChopAnd(Imaging imIn1, Imaging imIn2);