Merge pull request #902 from girder/image-bytes

Improve repr of image bytes

large_image/tilesource/utilities.py

@@ -34,6 +34,32 @@
 }
 
 
+class ImageBytes(bytes):
+    """Wrapper class to make repr of image bytes better in ipython."""
+
+    def __new__(cls, source: bytes, mimetype: str = None):
+        self = super().__new__(cls, source)
+        self._mime_type = mimetype
+        return self
+
+    @property
+    def mimetype(self):
+        return self._mime_type
+
+    def _repr_png_(self):
+        if self.mimetype == 'image/png':
+            return self
+
+    def _repr_jpeg_(self):
+        if self.mimetype == 'image/jpeg':
+            return self
+
+    def __repr__(self):
+        if self.mimetype:
+            return f'ImageBytes<{len(self)}> ({self.mimetype})'
+        return f'ImageBytes<{len(self)}> (wrapped image bytes)'
+
+
 def _encodeImageBinary(image, encoding, jpegQuality, jpegSubsampling, tiffCompression):
     """
     Encode a PIL Image to a binary representation of the image (a jpeg, png, or
@@ -55,13 +81,13 @@ def _encodeImageBinary(image, encoding, jpegQuality, jpegSubsampling, tiffCompre
         if image.mode not in ({'L', 'RGB', 'RGBA'} if simplejpeg else {'L', 'RGB'}):
             image = image.convert('RGB' if image.mode != 'LA' else 'L')
         if simplejpeg:
-            return simplejpeg.encode_jpeg(
+            return ImageBytes(simplejpeg.encode_jpeg(
                 _imageToNumpy(image)[0],
                 quality=jpegQuality,
                 colorspace=image.mode if image.mode in {'RGB', 'RGBA'} else 'GRAY',
                 colorsubsampling={-1: '444', 0: '444', 1: '422', 2: '420'}.get(
                     jpegSubsampling, str(jpegSubsampling).strip(':')),
-            )
+            ), mimetype='image/jpeg')
         params['quality'] = jpegQuality
         params['subsampling'] = jpegSubsampling
     elif encoding in {'TIFF', 'TILED'}:
@@ -74,7 +100,10 @@ def _encodeImageBinary(image, encoding, jpegQuality, jpegSubsampling, tiffCompre
         params['compress_level'] = 2
     output = io.BytesIO()
     image.save(output, encoding, **params)
-    return output.getvalue()
+    return ImageBytes(
+        output.getvalue(),
+        mimetype=f'image/{encoding.lower().replace("tiled", "tiff")}'
+    )
 
 
 def _encodeImage(image, encoding='JPEG', jpegQuality=95, jpegSubsampling=0,

test/test_source_base.py

@@ -506,3 +506,28 @@ def testCanReadList():
     imagePath = datastore.fetch('sample_image.ptif')
     assert len(large_image.canReadList(imagePath)) > 1
     assert any(canRead for source, canRead in large_image.canReadList(imagePath))
+
+
+def testImageBytes():
+    ib = large_image.tilesource.utilities.ImageBytes(b'abc')
+    assert ib == b'abc'
+    assert isinstance(ib, bytes)
+    assert 'ImageBytes' in repr(ib)
+    assert ib.mimetype is None
+    assert ib._repr_jpeg_() is None
+    assert ib._repr_png_() is None
+    ib = large_image.tilesource.utilities.ImageBytes(b'abc', 'image/jpeg')
+    assert ib.mimetype == 'image/jpeg'
+    assert 'ImageBytes' in repr(ib)
+    assert ib._repr_jpeg_() == b'abc'
+    assert ib._repr_png_() is None
+    ib = large_image.tilesource.utilities.ImageBytes(b'abc', 'image/png')
+    assert ib.mimetype == 'image/png'
+    assert 'ImageBytes' in repr(ib)
+    assert ib._repr_jpeg_() is None
+    assert ib._repr_png_() == b'abc'
+    ib = large_image.tilesource.utilities.ImageBytes(b'abc', 'other')
+    assert ib.mimetype == 'other'
+    assert 'ImageBytes' in repr(ib)
+    assert ib._repr_jpeg_() is None
+    assert ib._repr_png_() is None

test/test_source_gdal.py

@@ -11,6 +11,7 @@
 
 from large_image import constants
 from large_image.exceptions import TileSourceError, TileSourceInefficientError
+from large_image.tilesource.utilities import ImageBytes
 
 from . import utilities
 from .datastore import datastore
@@ -149,10 +150,15 @@ def testThumbnailFromGeotiffs():
     source = large_image_source_gdal.open(imagePath)
     # We get a thumbnail without a projection
     image, mimeType = source.getThumbnail(encoding='PNG')
+    assert isinstance(image, ImageBytes)
     assert image[:len(utilities.PNGHeader)] == utilities.PNGHeader
+    image, mimeType = source.getThumbnail(encoding='JPEG')
+    assert isinstance(image, ImageBytes)
+    assert image[:len(utilities.JPEGHeader)] == utilities.JPEGHeader
     # We get a different thumbnail with a projection
     source = large_image_source_gdal.open(imagePath, projection='EPSG:3857')
     image2, mimeType = source.getThumbnail(encoding='PNG')
+    assert isinstance(image2, ImageBytes)
     assert image2[:len(utilities.PNGHeader)] == utilities.PNGHeader
     assert image != image2
 

test/test_source_tiff.py

@@ -9,6 +9,7 @@
 import tifftools
 
 from large_image import constants
+from large_image.tilesource.utilities import ImageBytes
 
 from . import utilities
 from .datastore import datastore
@@ -271,19 +272,24 @@ def testThumbnails():
     assert image[:len(utilities.JPEGHeader)] == utilities.JPEGHeader
     defaultLength = len(image)
     image, mimeType = source.getThumbnail(encoding='PNG')
+    assert isinstance(image, ImageBytes)
     assert image[:len(utilities.PNGHeader)] == utilities.PNGHeader
     image, mimeType = source.getThumbnail(encoding='TIFF')
+    assert isinstance(image, ImageBytes)
     assert image[:len(utilities.TIFFHeader)] == utilities.TIFFHeader
     image, mimeType = source.getThumbnail(jpegQuality=10)
+    assert isinstance(image, ImageBytes)
     assert image[:len(utilities.JPEGHeader)] == utilities.JPEGHeader
     assert len(image) < defaultLength
     image, mimeType = source.getThumbnail(jpegSubsampling=2)
+    assert isinstance(image, ImageBytes)
     assert image[:len(utilities.JPEGHeader)] == utilities.JPEGHeader
     assert len(image) < defaultLength
     with pytest.raises(Exception):
         source.getThumbnail(encoding='unknown')
     # Test width and height using PNGs
     image, mimeType = source.getThumbnail(encoding='PNG')
+    assert isinstance(image, ImageBytes)
     assert image[:len(utilities.PNGHeader)] == utilities.PNGHeader
     (width, height) = struct.unpack('!LL', image[16:24])
     assert max(width, height) == 256

utilities/converter/large_image_converter/__init__.py

@@ -272,7 +272,7 @@ def _convert_via_vips(inputPathOrBuffer, outputPath, tempPath, forTiled=True,
     if type(inputPathOrBuffer) == pyvips.vimage.Image:
         source = 'vips image'
         image = inputPathOrBuffer
-    elif type(inputPathOrBuffer) == bytes:
+    elif isinstance(inputPathOrBuffer, bytes):
         source = 'buffer'
         image = pyvips.Image.new_from_buffer(inputPathOrBuffer, '')
     else: