Merge pull request #233 from wilsaj:image-html-repr

Conflicts:
	skimage/io/tests/test_collection.py

skimage/io/_io.py

@@ -1,14 +1,61 @@
-__all__ = ['imread', 'imread_collection', 'imsave', 'imshow', 'show',
+__all__ = ['Image', 'imread', 'imread_collection', 'imsave', 'imshow', 'show',
            'push', 'pop']
 
 from skimage.io._plugins import call as call_plugin
 from skimage.color import rgb2grey
 import numpy as np
 
+try:
+    import cStringIO as StringIO
+except ImportError:
+    import StringIO
+
+
 # Shared image queue
 _image_stack = []
 
 
+class Image(np.ndarray):
+    """Class representing Image data.
+
+    These objects have tags for image metadata and IPython display protocol
+    methods for image display.
+    """
+
+    tags = {'filename': '',
+            'EXIF': {},
+            'info': {}}
+
+    def __new__(cls, arr, **kwargs):
+        """Set the image data and tags according to given parameters.
+
+        Input:
+        ------
+        arr : ndarray
+            Image data.
+        kwargs : Image tags as keywords
+            Specified in the form ``tag0=value``, ``tag1=value``.
+
+        """
+        x = np.asarray(arr).view(cls)
+        for tag, value in Image.tags.items():
+            setattr(x, tag, kwargs.get(tag, getattr(arr, tag, value)))
+        return x
+
+    def _repr_png_(self):
+        return self._repr_image_format('png')
+
+    def _repr_jpeg_(self):
+        return self._repr_image_format('jpeg')
+
+    def _repr_image_format(self, format_str):
+        str_buffer = StringIO.StringIO()
+        imsave(str_buffer, self, format_str=format_str)
+        return_str = str_buffer.getvalue()
+        str_buffer.close()
+        return return_str
+
+
 def push(img):
     """Push an image onto the shared image stack.
 
@@ -77,7 +124,7 @@ def imread(fname, as_grey=False, plugin=None, flatten=None,
     if as_grey and getattr(img, 'ndim', 0) >= 3:
         img = rgb2grey(img)
 
-    return img
+    return Image(img)
 
 
 def imread_collection(load_pattern, conserve_memory=True,

skimage/io/_plugins/pil_plugin.py

@@ -59,17 +59,21 @@ def _palette_is_grayscale(pil_image):
     return np.allclose(np.diff(valid_palette), 0)
 
 
-def imsave(fname, arr):
+def imsave(fname, arr, format_str=None):
     """Save an image to disk.
 
     Parameters
     ----------
-    fname : str
+    fname : str or file-like object
         Name of destination file.
     arr : ndarray of uint8 or float
         Array (image) to save.  Arrays of data-type uint8 should have
         values in [0, 255], whereas floating-point arrays must be
         in [0, 1].
+    format_str: str
+        Format to save as, this is required if using a file-like object;
+        this is optional if fname is a string and the format can be
+        derived from the extension.
 
     Notes
     -----
@@ -101,7 +105,7 @@ def imsave(fname, arr):
         arr = arr.astype(np.uint8)
 
     img = Image.fromstring(mode, (arr.shape[1], arr.shape[0]), arr.tostring())
-    img.save(fname)
+    img.save(fname, format=format_str)
 
 
 def imshow(arr):

skimage/io/_plugins/qt_plugin.py

@@ -7,8 +7,8 @@ import sys
 window_manager.acquire('qt')
 
 try:
-    from PyQt4.QtGui import (QApplication, QMainWindow, QImage, QPixmap,
-                             QLabel, QWidget)
+    from PyQt4.QtGui import (QApplication, QImage,
+                             QLabel, QMainWindow, QPixmap, QWidget)
     from PyQt4 import QtCore, QtGui
     import sip
     import warnings
@@ -148,12 +148,21 @@ def _app_show():
         print 'No images to show.  See `imshow`.'
 
 
-def imsave(filename, img):
+def imsave(filename, img, format_str=None):
     # we can add support for other than 3D uint8 here...
     img = prepare_for_display(img)
     qimg = QImage(img.data, img.shape[1], img.shape[0],
                           img.strides[0], QImage.Format_RGB888)
-    saved = qimg.save(filename)
+    if _is_filelike(filename):
+        byte_array = QtCore.QByteArray()
+        qbuffer = QtCore.QBuffer(byte_array)
+        qbuffer.open(QtCore.QIODevice.ReadWrite)
+        saved = qimg.save(qbuffer, format_str.upper())
+        qbuffer.seek(0)
+        filename.write(qbuffer.readAll())
+        qbuffer.close()
+    else:
+        saved = qimg.save(filename)
     if not saved:
         from textwrap import dedent
         msg = dedent(
@@ -161,3 +170,7 @@ def imsave(filename, img):
             for the QT imsave plugin are:
             BMP, JPG, JPEG, PNG, PPM, TIFF, XBM, XPM''')
         raise RuntimeError(msg)
+
+
+def _is_filelike(possible_filelike):
+    return callable(getattr(possible_filelike, 'write', None))

skimage/io/tests/test_collection.py

@@ -8,6 +8,7 @@ from numpy.testing.decorators import skipif
 from skimage import data_dir
 from skimage.io import ImageCollection, MultiImage
 from skimage.io.collection import alphanumeric_key
+from skimage.io import Image as ioImage
 
 
 try:
@@ -54,7 +55,7 @@ class TestImageCollection():
     def test_getitem(self):
         num = len(self.collection)
         for i in range(-num, num):
-            assert type(self.collection[i]) is np.ndarray
+            assert type(self.collection[i]) is ioImage
         assert_array_almost_equal(self.collection[0],
                                   self.collection[-num])
 

skimage/io/tests/test_pil.py

@@ -33,6 +33,7 @@ def setup_module(self):
         pass
 
 
+
 @skipif(not PIL_available)
 def test_imread_flatten():
     # a color image is flattened
@@ -78,6 +79,20 @@ def test_imread_uint16():
     assert_array_almost_equal(img, expected)
 
 
+@skipif(not PIL_available)
+def test_repr_png():
+    img_path = os.path.join(data_dir, 'camera.png')
+    original_img = imread(img_path)
+    original_img_str = original_img._repr_png_()
+
+    with NamedTemporaryFile(suffix='.png', mode='r+') as temp_png:
+        temp_png.write(original_img_str)
+        temp_png.seek(0)
+        round_trip = imread(temp_png)
+
+    assert np.all(original_img == round_trip)
+
+
 # Big endian images not correctly loaded for PIL < 1.1.7
 # Renable test when PIL 1.1.7 is more common.
 @skipif(True)