To support io.Bytesio (#339)

* To support io.Bytesio

* fix doc error

* fix format

* add unit test

* fix assert condition

* fix np ndarray compare in an error way

* fix type error, cast the LocalPath to pathlib.Path

keras_preprocessing/image/utils.py

@@ -3,6 +3,7 @@
 import io
 import os
 import warnings
+from pathlib import Path
 
 import numpy as np
 
@@ -77,7 +78,7 @@ def load_img(path, grayscale=False, color_mode='rgb', target_size=None,
     """Loads an image into PIL format.
 
     # Arguments
-        path: Path to image file.
+        path: Path (string), pathlib.Path object, or io.BytesIO stream to image file.
         grayscale: DEPRECATED use `color_mode="grayscale"`.
         color_mode: The desired image format. One of "grayscale", "rgb", "rgba".
             "grayscale" supports 8-bit images and 32-bit signed integer images.
@@ -101,6 +102,7 @@ def load_img(path, grayscale=False, color_mode='rgb', target_size=None,
     # Raises
         ImportError: if PIL is not available.
         ValueError: if interpolation method is not supported.
+        TypeError: type of 'path' should be path-like or io.Byteio.
     """
     if grayscale is True:
         warnings.warn('grayscale is deprecated. Please use '
@@ -109,56 +111,65 @@ def load_img(path, grayscale=False, color_mode='rgb', target_size=None,
     if pil_image is None:
         raise ImportError('Could not import PIL.Image. '
                           'The use of `load_img` requires PIL.')
-    with open(path, 'rb') as f:
-        img = pil_image.open(io.BytesIO(f.read()))
-        if color_mode == 'grayscale':
-            # if image is not already an 8-bit, 16-bit or 32-bit grayscale image
-            # convert it to an 8-bit grayscale image.
-            if img.mode not in ('L', 'I;16', 'I'):
-                img = img.convert('L')
-        elif color_mode == 'rgba':
-            if img.mode != 'RGBA':
-                img = img.convert('RGBA')
-        elif color_mode == 'rgb':
-            if img.mode != 'RGB':
-                img = img.convert('RGB')
-        else:
-            raise ValueError('color_mode must be "grayscale", "rgb", or "rgba"')
-        if target_size is not None:
-            width_height_tuple = (target_size[1], target_size[0])
-            if img.size != width_height_tuple:
-                if interpolation not in _PIL_INTERPOLATION_METHODS:
-                    raise ValueError(
-                        'Invalid interpolation method {} specified. Supported '
-                        'methods are {}'.format(
-                            interpolation,
-                            ", ".join(_PIL_INTERPOLATION_METHODS.keys())))
-                resample = _PIL_INTERPOLATION_METHODS[interpolation]
-
-                if keep_aspect_ratio:
-                    width, height = img.size
-                    target_width, target_height = width_height_tuple
-
-                    crop_height = (width * target_height) // target_width
-                    crop_width = (height * target_width) // target_height
-
-                    # Set back to input height / width
-                    # if crop_height / crop_width is not smaller.
-                    crop_height = min(height, crop_height)
-                    crop_width = min(width, crop_width)
-
-                    crop_box_hstart = (height - crop_height) // 2
-                    crop_box_wstart = (width - crop_width) // 2
-                    crop_box_wend = crop_box_wstart + crop_width
-                    crop_box_hend = crop_box_hstart + crop_height
-                    crop_box = [crop_box_wstart, crop_box_hstart,
-                                crop_box_wend, crop_box_hend]
-
-                    img = img.resize(width_height_tuple, resample,
-                                     box=crop_box)
-                else:
-                    img = img.resize(width_height_tuple, resample)
-        return img
+    if isinstance(path, io.BytesIO):
+        img = pil_image.open(path)
+    elif isinstance(path, (Path, bytes, str)):
+        if isinstance(path, Path):
+            path = str(path.resolve())
+        with open(path, 'rb') as f:
+            img = pil_image.open(io.BytesIO(f.read()))
+    else:
+        raise TypeError('path should be path-like or io.BytesIO'
+                        ', not {}'.format(type(path)))
+
+    if color_mode == 'grayscale':
+        # if image is not already an 8-bit, 16-bit or 32-bit grayscale image
+        # convert it to an 8-bit grayscale image.
+        if img.mode not in ('L', 'I;16', 'I'):
+            img = img.convert('L')
+    elif color_mode == 'rgba':
+        if img.mode != 'RGBA':
+            img = img.convert('RGBA')
+    elif color_mode == 'rgb':
+        if img.mode != 'RGB':
+            img = img.convert('RGB')
+    else:
+        raise ValueError('color_mode must be "grayscale", "rgb", or "rgba"')
+    if target_size is not None:
+        width_height_tuple = (target_size[1], target_size[0])
+        if img.size != width_height_tuple:
+            if interpolation not in _PIL_INTERPOLATION_METHODS:
+                raise ValueError(
+                    'Invalid interpolation method {} specified. Supported '
+                    'methods are {}'.format(
+                        interpolation,
+                        ", ".join(_PIL_INTERPOLATION_METHODS.keys())))
+            resample = _PIL_INTERPOLATION_METHODS[interpolation]
+
+            if keep_aspect_ratio:
+                width, height = img.size
+                target_width, target_height = width_height_tuple
+
+                crop_height = (width * target_height) // target_width
+                crop_width = (height * target_width) // target_height
+
+                # Set back to input height / width
+                # if crop_height / crop_width is not smaller.
+                crop_height = min(height, crop_height)
+                crop_width = min(width, crop_width)
+
+                crop_box_hstart = (height - crop_height) // 2
+                crop_box_wstart = (width - crop_width) // 2
+                crop_box_wend = crop_box_wstart + crop_width
+                crop_box_hend = crop_box_hstart + crop_height
+                crop_box = [
+                    crop_box_wstart, crop_box_hstart, crop_box_wend,
+                    crop_box_hend
+                ]
+                img = img.resize(width_height_tuple, resample, box=crop_box)
+            else:
+                img = img.resize(width_height_tuple, resample)
+    return img
 
 
 def list_pictures(directory, ext=('jpg', 'jpeg', 'bmp', 'png', 'ppm', 'tif',

tests/image/utils_test.py

@@ -1,4 +1,6 @@
+import io
 import resource
+from pathlib import Path
 
 import numpy as np
 import PIL
@@ -193,6 +195,28 @@ def test_load_img(tmpdir):
     loaded_im_array = utils.img_to_array(loaded_im, dtype='int32')
     assert loaded_im_array.shape == (25, 25, 1)
 
+    # Test different path type
+    with open(filename_grayscale_32bit, 'rb') as f:
+        _path = io.BytesIO(f.read())  # io.Bytesio
+    loaded_im = utils.load_img(_path, color_mode='grayscale')
+    loaded_im_array = utils.img_to_array(loaded_im, dtype=np.int32)
+    assert np.all(loaded_im_array == original_grayscale_32bit_array)
+
+    _path = filename_grayscale_32bit    # str
+    loaded_im = utils.load_img(_path, color_mode='grayscale')
+    loaded_im_array = utils.img_to_array(loaded_im, dtype=np.int32)
+    assert np.all(loaded_im_array == original_grayscale_32bit_array)
+
+    _path = filename_grayscale_32bit.encode()  # bytes
+    loaded_im = utils.load_img(_path, color_mode='grayscale')
+    loaded_im_array = utils.img_to_array(loaded_im, dtype=np.int32)
+    assert np.all(loaded_im_array == original_grayscale_32bit_array)
+
+    _path = Path(tmpdir / 'grayscale_32bit_utils.tiff')  # Path
+    loaded_im = utils.load_img(_path, color_mode='grayscale')
+    loaded_im_array = utils.img_to_array(loaded_im, dtype=np.int32)
+    assert np.all(loaded_im_array == original_grayscale_32bit_array)
+
     # Check that exception is raised if interpolation not supported.
 
     loaded_im = utils.load_img(filename_rgb, interpolation="unsupported")