Merge pull request #2723 from jasongrout/memoryview

Change media widgets to use memory views.

Author: jasongrout

ipywidgets/widgets/tests/test_widget_image.py

@@ -149,8 +149,9 @@ def test_value_repr_length():
     with get_logo_png() as LOGO_PNG:
         with open(LOGO_PNG, 'rb') as f:
             img = Image.from_file(f)
-            assert len(img.__repr__()) < 120
-            assert img.__repr__().endswith("...')")
+            assert len(img.__repr__()) < 140
+            assert img.__repr__().endswith(")")
+            assert img.__repr__()[-5:-2] == '...'
 
 
 def test_value_repr_url():

ipywidgets/widgets/trait_types.py

@@ -146,6 +146,34 @@ def date_from_json(js, manager):
     'to_json': date_to_json
 }
 
+class ByteMemoryView(traitlets.TraitType):
+    """A trait for memory views of bytes."""
+
+    default_value = memoryview(b'')
+    info_text = 'a memory view object'
+
+    def validate(self, obj, value):
+        if isinstance(value, memoryview) and value.format == 'B':
+            return value
+        self.error(obj, value)
+
+    def default_value_repr(self):
+        return repr(self.default_value.tobytes())
+
+class CByteMemoryView(ByteMemoryView):
+    """A casting version of the byte memory view trait."""
+
+    def validate(self, obj, value):
+        if isinstance(value, memoryview) and value.format == 'B':
+            return value
+
+        try:
+            mv = memoryview(value)
+            if mv.format != 'B':
+                mv = mv.cast('B')
+            return mv
+        except Exception:
+            self.error(obj, value)
 
 class InstanceDict(traitlets.Instance):
     """An instance trait which coerces a dict to an instance.

ipywidgets/widgets/widget_media.py

@@ -7,8 +7,8 @@
 from .domwidget import DOMWidget
 from .valuewidget import ValueWidget
 from .widget import register
-from traitlets import Unicode, CUnicode, Bytes, Bool
-from .trait_types import bytes_serialization
+from traitlets import Unicode, CUnicode, Bool
+from .trait_types import CByteMemoryView
 
 
 @register
@@ -23,7 +23,7 @@ class _Media(DOMWidget, ValueWidget, CoreWidget):
     """
 
     # Define the custom state properties to sync with the front-end
-    value = Bytes(help="The media data as a byte string.").tag(sync=True, **bytes_serialization)
+    value = CByteMemoryView(help="The media data as a memory view of bytes.").tag(sync=True)
 
     @classmethod
     def _from_file(cls, tag, filename, **kwargs):
@@ -116,12 +116,11 @@ def _get_repr(self, cls):
 
         # Return value first like a ValueWidget
         signature = []
-        sig_value = repr(self.value)
-        prefix, rest = sig_value.split("'", 1)
-        content = rest[:-1]
-        if len(content) > 100:
-            sig_value = "{}'{}...'".format(prefix, content[0:100])
-        signature.append('{}={}'.format('value', sig_value))
+
+        sig_value = 'value={!r}'.format(self.value[:40].tobytes())
+        if self.value.nbytes > 40:
+            sig_value = sig_value[:-1]+"..."+sig_value[-1]
+        signature.append(sig_value)
 
         for key in super(cls, self)._repr_keys():
             if key == 'value':

packages/schema/generate-spec.py

@@ -10,7 +10,7 @@
 
 import ipywidgets as widgets
 from ipywidgets import Color
-from ipywidgets.widgets.trait_types import TypedTuple
+from ipywidgets.widgets.trait_types import TypedTuple, ByteMemoryView
 from ipywidgets.widgets.widget_link import Link
 
 HEADER = '''# Model State
@@ -40,46 +40,46 @@
 }
 
 
-def widget_type(widget, widget_list):
+def trait_type(trait, widget_list):
     attributes = {}
-    if isinstance(widget, CaselessStrEnum):
+    if isinstance(trait, CaselessStrEnum):
         w_type = 'string'
-        attributes['enum'] = widget.values
-    elif isinstance(widget, Unicode):
+        attributes['enum'] = trait.values
+    elif isinstance(trait, Unicode):
         w_type = 'string'
-    elif isinstance(widget, (Tuple, List)):
+    elif isinstance(trait, (Tuple, List)):
         w_type = 'array'
-    elif isinstance(widget, TypedTuple):
+    elif isinstance(trait, TypedTuple):
         w_type = 'array'
-        attributes['items'] = widget_type(widget._trait, widget_list)
-    elif isinstance(widget, Bool):
+        attributes['items'] = trait_type(trait._trait, widget_list)
+    elif isinstance(trait, Bool):
         w_type = 'bool'
-    elif isinstance(widget, (CFloat, Float)):
+    elif isinstance(trait, (CFloat, Float)):
         w_type = 'float'
-    elif isinstance(widget, (CInt, Int)):
+    elif isinstance(trait, (CInt, Int)):
         w_type = 'int'
-    elif isinstance(widget, Color):
+    elif isinstance(trait, Color):
         w_type = 'color'
-    elif isinstance(widget, Dict):
+    elif isinstance(trait, Dict):
         w_type = 'object'
-    elif isinstance(widget, Bytes):
+    elif isinstance(trait, Bytes) or isinstance(trait, ByteMemoryView):
         w_type = 'bytes'
-    elif isinstance(widget, Instance) and issubclass(widget.klass,
+    elif isinstance(trait, Instance) and issubclass(trait.klass,
                                                      widgets.Widget):
         w_type = 'reference'
-        attributes['widget'] = widget.klass.__name__
+        attributes['widget'] = trait.klass.__name__
         # ADD the widget to this documenting list
-        if (widget.klass not in [i[1] for i in widget_list]
-                and widget.klass is not widgets.Widget):
-            widget_list.append((widget.klass.__name__, widget.klass))
-    elif isinstance(widget, Any):
+        if (trait.klass not in [i[1] for i in widget_list]
+                and trait.klass is not widgets.Widget):
+            widget_list.append((trait.klass.__name__, trait.klass))
+    elif isinstance(trait, Any):
         # In our case, these all happen to be values that are converted to
         # strings
         w_type = 'label'
     else:
-        w_type = widget.__class__.__name__
+        w_type = trait.__class__.__name__
     attributes['type'] = w_type
-    if widget.allow_none:
+    if trait.allow_none:
         attributes['allow_none'] = True
     return attributes
 
@@ -91,7 +91,7 @@ def jsdefault(trait):
             return 'reference to new instance'
     else:
         default = trait.default_value
-        if isinstance(default, bytes):
+        if isinstance(default, bytes) or isinstance(default, memoryview):
             default = trait.default_value_repr()
     return default
 
@@ -163,7 +163,7 @@ def jsonify(identifier, widget, widget_list):
             help=trait.help or '',
             default=jsdefault(trait)
         )
-        attribute.update(widget_type(trait, widget_list))
+        attribute.update(trait_type(trait, widget_list))
         attributes.append(attribute)
 
     return dict(model=model, view=view, attributes=attributes)

packages/schema/jupyterwidgetmodels.latest.md

@@ -100,7 +100,7 @@ Attribute        | Type             | Default          | Help
 `loop`           | boolean          | `true`           | When true, the audio will start from the beginning after finishing
 `tabbable`       | `null` or boolean | `null`           | Is widget tabbable?
 `tooltip`        | `null` or string | `null`           | A tooltip caption.
-`value`          | Bytes            | `b''`            | The media data as a byte string.
+`value`          | Bytes            | `b''`            | The media data as a memory view of bytes.
 
 ### BoundedFloatTextModel (@jupyter-widgets/controls, 1.5.0); FloatTextView (@jupyter-widgets/controls, 1.5.0)
 
@@ -330,7 +330,7 @@ Attribute        | Type             | Default          | Help
 `layout`         | reference to Layout widget | reference to new instance | 
 `tabbable`       | `null` or boolean | `null`           | Is widget tabbable?
 `tooltip`        | `null` or string | `null`           | A tooltip caption.
-`value`          | Bytes            | `b''`            | The media data as a byte string.
+`value`          | Bytes            | `b''`            | The media data as a memory view of bytes.
 
 ### DatePickerModel (@jupyter-widgets/controls, 1.5.0); DatePickerView (@jupyter-widgets/controls, 1.5.0)
 
@@ -630,7 +630,7 @@ Attribute        | Type             | Default          | Help
 `layout`         | reference to Layout widget | reference to new instance | 
 `tabbable`       | `null` or boolean | `null`           | Is widget tabbable?
 `tooltip`        | `null` or string | `null`           | A tooltip caption.
-`value`          | Bytes            | `b''`            | The media data as a byte string.
+`value`          | Bytes            | `b''`            | The media data as a memory view of bytes.
 `width`          | string           | `''`             | Width of the image in pixels. Use layout.width for styling the widget.
 
 ### IntProgressModel (@jupyter-widgets/controls, 1.5.0); ProgressView (@jupyter-widgets/controls, 1.5.0)
@@ -1136,7 +1136,7 @@ Attribute        | Type             | Default          | Help
 `loop`           | boolean          | `true`           | When true, the video will start from the beginning after finishing
 `tabbable`       | `null` or boolean | `null`           | Is widget tabbable?
 `tooltip`        | `null` or string | `null`           | A tooltip caption.
-`value`          | Bytes            | `b''`            | The media data as a byte string.
+`value`          | Bytes            | `b''`            | The media data as a memory view of bytes.
 `width`          | string           | `''`             | Width of the video in pixels.
 
 ### OutputModel (@jupyter-widgets/output, 1.0.0); OutputView (@jupyter-widgets/output, 1.0.0)