Merge pull request #18 from albarji/bugfix/alpha

Solves #17

neuralstyle/imagemagick.py

@@ -1,28 +1,19 @@
 # Convenience functions to perform Image Magicks
 from subprocess import run, PIPE
 from glob import glob
-from tempfile import TemporaryDirectory
 from neuralstyle.utils import filename
 
 
 def convert(origin, dest):
-    """Transforms the format of an image in a file, by creating a new file with the new format
-
-    If the input file has several layers, they are flattened.
-    """
-    command = "convert " + origin + " -flatten " + dest
-    run(command, shell=True)
+    """Transforms the format of an image in a file, by creating a new file with the new format"""
+    if ismultilayer(origin):
+        raise ValueError("Cannot operate with multilayer images")
+    run("convert %s %s" % (origin, dest), shell=True)
 
 
 def shape(imfile):
-    """Returns the shape of an image file
-
-    If the input file has several layers, it is flattened before computing the shape.
-    """
-    tmpdir = TemporaryDirectory()
-    tmpname = tmpdir.name + "/" + "image.png"
-    convert(imfile, tmpname)
-    result = run("convert " + tmpname + ' -format "%w %h" info:', shell=True, check=True, stdout=PIPE)
+    """Returns the shape of an image file"""
+    result = run("convert " + imfile + ' -format "%w %h" info:', shell=True, check=True, stdout=PIPE)
     return [int(x) for x in result.stdout.decode("utf-8").split(" ")]
 
 
@@ -90,6 +81,8 @@ def composite(imfiles, outname):
 
 def extractalpha(imfile, rgbfile, alphafile):
     """Decomposes an image file into the RGB channels and the alpha channel, saving both as separate image files"""
+    if ismultilayer(imfile):
+        raise ValueError("Cannot operate with multilayer images")
     # Alpha channel extraction
     command = "convert -alpha extract %s %s" % (imfile, alphafile)
     run(command, shell=True, check=True)
@@ -119,3 +112,8 @@ def equalimages(imfile1, imfile2):
     if result.returncode == 2:
         raise IOError("Error while calling imagemagick compare method")
     return result.returncode == 0
+
+
+def ismultilayer(imfile):
+    """Returns whether an image file contains multiple layers"""
+    return len(shape(imfile)) > 2

tests/algorithms_tests.py

@@ -11,6 +11,18 @@
 STYLES = "/app/entrypoint/tests/styles/"
 
 
+def assertalldifferent(pattern, expected=None):
+    """Asserts that all images that follow a given glob pattern have different contents
+
+    An expected number of images can also be provided to be checked.
+    """
+    files = glob(pattern)
+    if expected is not None:
+        assert len(files) == expected
+    for f1, f2 in zip(files, files[1:]):
+        assert not equalimages(f1, f2)
+
+
 def test_styletransfer_gatys():
     """Style transfer works without error for the Gatys algorithm"""
     tmpdir = TemporaryDirectory()
@@ -79,11 +91,7 @@ def test_styletransfer_ss():
         tmpdir = TemporaryDirectory()
         styletransfer([CONTENTS + img], [STYLES + "cubism.jpg"], tmpdir.name, alg=alg, size=100,
                       stylescales=stylescales)
-        files = glob(tmpdir.name + "/" + filename(img) + "*cubism*")
-        # Check correct number of generated images, and that they are different
-        assert len(files) == len(stylescales)
-        for f1, f2 in zip(files, files[1:]):
-            assert not equalimages(f1, f2)
+        assertalldifferent(tmpdir.name + "/" + filename(img) + "*cubism*", len(stylescales))
 
 
 def test_styletransfer_sw():
@@ -94,11 +102,7 @@ def test_styletransfer_sw():
     tmpdir = TemporaryDirectory()
     styletransfer([CONTENTS + img], [STYLES + "cubism.jpg"], tmpdir.name, alg=alg, size=100,
                   weights=styleweights)
-    files = glob(tmpdir.name + "/" + filename(img) + "*cubism*")
-    # Check correct number of generated images, and that they are different
-    assert len(files) == len(styleweights)
-    for f1, f2 in zip(files, files[1:]):
-        assert not equalimages(f1, f2)
+    assertalldifferent(tmpdir.name + "/" + filename(img) + "*cubism*", len(styleweights))
 
 
 def test_neuraltile():
@@ -124,3 +128,31 @@ def test_formatpsd():
     tmpdir = TemporaryDirectory()
     styletransfer(contents, [STYLES + "cubism.jpg"], tmpdir.name, alg="chen-schmidt-inverse")
     assert len(glob(tmpdir.name + "/*cubism*")) == 1
+
+
+def test_alpha():
+    """Transformation of images with an alpha channel preserve transparency"""
+    tmpdir = TemporaryDirectory()
+    # Transform image with alpha
+    styletransfer([CONTENTS + "dockersmallalpha.png"], [STYLES + "cubism.jpg"], tmpdir.name, alg="chen-schmidt-inverse")
+    assert len(glob(tmpdir.name + "/*dockersmallalpha_cubism*")) == 1
+    # Transform image without alpha
+    styletransfer([CONTENTS + "dockersmall.png"], [STYLES + "cubism.jpg"], tmpdir.name, alg="chen-schmidt-inverse")
+    assert len(glob(tmpdir.name + "/*dockersmall_cubism*")) == 1
+    # Check correct that generated image are different
+    assertalldifferent(tmpdir.name + "/*cubism*")
+
+
+def test_alpha_tiling():
+    """Transformation of images with an alpha channel preserve transparency, even when a tiling strategy is used"""
+    tmpdir = TemporaryDirectory()
+    # Transform image with alpha
+    styletransfer([CONTENTS + "dockersmallalpha.png"], [STYLES + "cubism.jpg"], tmpdir.name, alg="chen-schmidt-inverse",
+                  maxtilesize=150)
+    assert len(glob(tmpdir.name + "/*dockersmallalpha_cubism*")) == 1
+    # Transform image without alpha
+    styletransfer([CONTENTS + "dockersmall.png"], [STYLES + "cubism.jpg"], tmpdir.name, alg="chen-schmidt-inverse",
+                  maxtilesize=150)
+    assert len(glob(tmpdir.name + "/*dockersmall_cubism*")) == 1
+    # Check correct that generated image are different
+    assertalldifferent(tmpdir.name + "/*cubism*")

tests/imagemagick_tests.py

@@ -47,17 +47,6 @@ def test_convert_nolayers():
             assert shape(outname) == shape(content)
 
 
-def test_convert_layers():
-    """Convert a single image with layers works as expected"""
-    for content in [CONTENTS + f for f in ["oldtelephone.psd"]]:
-        for ext in [".png", ".jpg", ".psd", ".tga"]:
-            tmpdir = TemporaryDirectory()
-            outname = tmpdir.name + "/" + "output" + ext
-            convert(content, outname)
-            assert len(glob(tmpdir.name + "/" + filename(outname) + ext)) == 1
-            assert shape(outname) == shape(content)
-
-
 def test_resize_keepproportions():
     """Resizing an image without changing proportions works correctly"""
     tmpdir = TemporaryDirectory()