upstream/ipython Commit - r20515:3b62ff3f

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Migrating Widgets to IPython 3

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Migrating Widgets to IPython 3

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==============================

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==============================

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Upgrading Notebooks

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Upgrading Notebooks

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-------------------

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-------------------

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1. The first thing you'll notice when upgrading an IPython 2.0 widget

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1. The first thing you'll notice when upgrading an IPython 2.0 widget

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notebook to IPython 3.0 is the "Notebook converted" dialog. Click

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notebook to IPython 3.0 is the "Notebook converted" dialog. Click

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"ok".

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"ok".

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2. All of the widgets distributed with IPython have been renamed. The

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2. All of the widgets distributed with IPython have been renamed. The

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"Widget" suffix was removed from the end of the class name. i.e.

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"Widget" suffix was removed from the end of the class name. i.e.

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``ButtonWidget`` is now ``Button``.

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``ButtonWidget`` is now ``Button``.

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3. ``ContainerWidget`` was renamed to ``Box``.

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3. ``ContainerWidget`` was renamed to ``Box``.

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4. ``PopupWidget`` was removed from IPython. If you use the

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4. ``PopupWidget`` was removed from IPython. If you use the

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``PopupWidget``, try using a ``Box`` widget instead. If your notebook

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``PopupWidget``, try using a ``Box`` widget instead. If your notebook

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can't live without the popup functionality, subclass the ``Box``

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can't live without the popup functionality, subclass the ``Box``

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widget (both in Python and JS) and use JQuery UI's ``draggable()``

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widget (both in Python and JS) and use JQuery UI's ``draggable()``

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and ``resizable()`` methods to mimic the behavior.

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and ``resizable()`` methods to mimic the behavior.

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5. ``add_class`` and ``remove_class`` were removed. More often than not

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5. ``add_class`` and ``remove_class`` were removed. More often than not

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a new attribute exists on the widget that allows you to achieve the

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a new attribute exists on the widget that allows you to achieve the

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same explicitly. i.e. the ``Button`` widget now has a

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same explicitly. i.e. the ``Button`` widget now has a

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``button_style`` attribute which you can set to 'primary', 'success',

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``button_style`` attribute which you can set to 'primary', 'success',

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'info', 'warning', 'danger', or '' instead of using ``add_class`` to

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'info', 'warning', 'danger', or '' instead of using ``add_class`` to

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add the bootstrap class. ``VBox`` and ``HBox`` classes (flexible

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add the bootstrap class. ``VBox`` and ``HBox`` classes (flexible

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``Box`` subclasses) were added that allow you to avoid using

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``Box`` subclasses) were added that allow you to avoid using

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``add_class`` and ``remove_class`` to make flexible box model

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``add_class`` and ``remove_class`` to make flexible box model

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layouts. As a last resort, if you can't find a built in attribute for

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layouts. As a last resort, if you can't find a built in attribute for

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the class you want to use, a new ``_dom_classes`` list trait was

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the class you want to use, a new ``_dom_classes`` list trait was

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added, which combines ``add_class`` and ``remove_class`` into one

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added, which combines ``add_class`` and ``remove_class`` into one

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stateful list.

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stateful list.

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6. ``set_css`` and ``get_css`` were removed in favor of explicit style

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6. ``set_css`` and ``get_css`` were removed in favor of explicit style

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attributes - ``visible``, ``width``, ``height``, ``padding``,

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attributes - ``visible``, ``width``, ``height``, ``padding``,

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``margin``, ``color``, ``background_color``, ``border_color``,

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``margin``, ``color``, ``background_color``, ``border_color``,

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``border_width``, ``border_radius``, ``border_style``,

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``border_width``, ``border_radius``, ``border_style``,

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``font_style``, ``font_weight``, ``font_size``, and ``font_family``

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``font_style``, ``font_weight``, ``font_size``, and ``font_family``

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are a few. If you can't find a trait to see the css attribute you

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are a few. If you can't find a trait to see the css attribute you

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need, you can, in order of preference, (A) subclass to create your

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need, you can, in order of preference, (A) subclass to create your

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own custom widget, (B) use CSS and the ``_dom_classes`` trait to set

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own custom widget, (B) use CSS and the ``_dom_classes`` trait to set

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``_dom_classes``, or (C) use the ``_css`` dictionary to set CSS

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``_dom_classes``, or (C) use the ``_css`` dictionary to set CSS

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styling like ``set_css`` and ``get_css``.

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styling like ``set_css`` and ``get_css``.

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Upgrading Custom Widgets

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Upgrading Custom Widgets

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------------------------

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------------------------

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Javascript

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Javascript

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~~~~~~~~~~

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~~~~~~~~~~

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1. If you are distributing your widget and decide to use the deferred

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1. If you are distributing your widget and decide to use the deferred

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loading technique (preferred), you can remove all references to the

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loading technique (preferred), you can remove all references to the

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WidgetManager and the register model/view calls (see the Python

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WidgetManager and the register model/view calls (see the Python

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section below for more information).

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section below for more information).

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2. In 2.0 require.js was used incorrectly, that has been fixed and now

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2. In 2.0 require.js was used incorrectly, that has been fixed and now

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loading works more like Python's import. Requiring

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loading works more like Python's import. Requiring

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``widgets/js/widget`` doesn't import the ``WidgetManager`` class,

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``widgets/js/widget`` doesn't import the ``WidgetManager`` class,

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instead it imports a dictionary that exposes the classes within that

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instead it imports a dictionary that exposes the classes within that

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module:

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module:

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.. code:: javascript

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.. code:: javascript

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{

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{

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'WidgetModel': WidgetModel,

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'WidgetModel': WidgetModel,

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'WidgetView': WidgetView,

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'WidgetView': WidgetView,

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'DOMWidgetView': DOMWidgetView,

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'DOMWidgetView': DOMWidgetView,

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'ViewList': ViewList,

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'ViewList': ViewList,

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}

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}

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If you decide to continue to use the widget registry (by registering

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If you decide to continue to use the widget registry (by registering

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your widgets with the manager), you can import a dictionary with a

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your widgets with the manager), you can import a dictionary with a

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handle to the WidgetManager class by requiring

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handle to the WidgetManager class by requiring

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``widgets/js/manager``. Doing so will import:

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``widgets/js/manager``. Doing so will import:

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.. code:: javascript

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.. code:: javascript

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{'WidgetManager': WidgetManager}

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{'WidgetManager': WidgetManager}

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3. Don't rely on the ``IPython`` namespace for anything. To inherit from

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3. Don't rely on the ``IPython`` namespace for anything. To inherit from

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the DOMWidgetView, WidgetView, or WidgetModel, require

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the DOMWidgetView, WidgetView, or WidgetModel, require

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``widgets/js/widget`` as ``widget``. If you were inheriting from

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``widgets/js/widget`` as ``widget``. If you were inheriting from

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DOMWidgetView, and the code looked like this:

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DOMWidgetView, and the code looked like this:

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.. code:: javascript

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.. code:: javascript

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IPython.DOMWidgetView.extend({...})

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IPython.DOMWidgetView.extend({...})

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It would become this:

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It would become this:

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.. code:: javascript

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.. code:: javascript

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widget.DOMWidgetView.extend({...})

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widget.DOMWidgetView.extend({...})

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4. Custom models are encouraged. When possible, it's recommended to move

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4. Custom models are encouraged. When possible, it's recommended to move

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your code into a custom model, so actions are performed 1 time,

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your code into a custom model, so actions are performed 1 time,

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instead of N times where N is the number of displayed views.

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instead of N times where N is the number of displayed views.

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Python

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Python

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~~~~~~

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~~~~~~

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Generally, custom widget Python code can remain unchanged. If you

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Generally, custom widget Python code can remain unchanged. If you

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distribute your custom widget, you may be using ``display`` and

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distribute your custom widget, you may be using ``display`` and

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``Javascript`` to publish the widget's Javascript to the front-end. That

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``Javascript`` to publish the widget's Javascript to the front-end. That

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is no longer the recommended way of distributing widget Javascript.

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is no longer the recommended way of distributing widget Javascript.

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Instead have the user install the Javascript to his/her nbextension

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Instead have the user install the Javascript to his/her nbextension

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directory or their profile's static directory. Then use the new

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directory or their profile's static directory. Then use the new

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``_view_module`` and ``_model_module`` traitlets in combination with

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``_view_module`` and ``_model_module`` traitlets in combination with

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``_view_name`` and ``_model_name`` to instruct require.js on how to load

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``_view_name`` and ``_model_name`` to instruct require.js on how to load

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the widget's Javascript. The Javascript is then loaded when the widget

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the widget's Javascript. The Javascript is then loaded when the widget

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is used for the first time.

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is used for the first time.

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Details

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Details

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-------

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-------

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Asynchronous

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Asynchronous

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~~~~~~~~~~~~

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~~~~~~~~~~~~

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In the IPython 2.x series the only way to register custom widget views

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In the IPython 2.x series the only way to register custom widget views

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and models was to use the registry in the widget manager. Unfortunately,

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and models was to use the registry in the widget manager. Unfortunately,

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using this method made packing custom widgets difficult. The widget

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using this method made packing custom widgets difficult. The widget

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maintainer had to either use the rich display framework to push the

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maintainer had to either use the rich display framework to push the

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widget's Javascript to the notebook or instruct the users to install the

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widget's Javascript to the notebook or instruct the users to install the

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Javascript by hand in a custom profile. With the first method, the

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Javascript by hand in a custom profile. With the first method, the

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maintainer would have to be careful about when the Javascript was pushed

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maintainer would have to be careful about when the Javascript was pushed

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to the font-end. If the Javascript was pushed on Python widget

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to the font-end. If the Javascript was pushed on Python widget

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``import``, the widgets wouldn't work after page refresh. This is

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``import``, the widgets wouldn't work after page refresh. This is

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because refreshing the page does not restart the kernel, and the Python

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because refreshing the page does not restart the kernel, and the Python

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``import`` statement only runs once in a given kernel instance (unless

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``import`` statement only runs once in a given kernel instance (unless

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you reload the Python modules, which isn't straight forward). This meant

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you reload the Python modules, which isn't straight forward). This meant

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the maintainer would have to have a separate ``push_js()`` method that

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the maintainer would have to have a separate ``push_js()`` method that

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the user would have to call after importing the widget's Python code.

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the user would have to call after importing the widget's Python code.

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Our solution was to add support for loading widget views and models

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Our solution was to add support for loading widget views and models

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using require.js paths. Thus the comm and widget frameworks now support

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using require.js paths. Thus the comm and widget frameworks now support

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lazy loading. To do so, everything had to be converted to asynchronous

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lazy loading. To do so, everything had to be converted to asynchronous

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code. HTML5 promises are used to accomplish that

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code. HTML5 promises are used to accomplish that

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(`#6818 <https://github.com/ipython/ipython/pull/6818>`__,

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(`#6818 <https://github.com/ipython/ipython/pull/6818>`__,

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`#6914 <https://github.com/ipython/ipython/pull/6914>`__).

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`#6914 <https://github.com/ipython/ipython/pull/6914>`__).

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Symmetry

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Symmetry

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~~~~~~~~

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~~~~~~~~

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In IPython 3.0, widgets can be instantiated from the front-end

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In IPython 3.0, widgets can be instantiated from the front-end

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(`#6664 <https://github.com/ipython/ipython/pull/6664>`__). On top of

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(`#6664 <https://github.com/ipython/ipython/pull/6664>`__). On top of

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this, a widget persistence API was added

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this, a widget persistence API was added

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(`#7163 <https://github.com/ipython/ipython/pull/7163>`__,

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(`#7163 <https://github.com/ipython/ipython/pull/7163>`__,

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`#7227 <https://github.com/ipython/ipython/pull/7227>`__). With the

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`#7227 <https://github.com/ipython/ipython/pull/7227>`__). With the

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widget persistence API, you can persist your widget instances using

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widget persistence API, you can persist your widget instances using

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Javascript. This makes it easy to persist your widgets to your notebook

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Javascript. This makes it easy to persist your widgets to your notebook

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document (with a small amount of custom JS). By default, the widgets are

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document (with a small amount of custom JS). By default, the widgets are

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persisted to your web browsers local storage which makes them reappear

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persisted to your web browsers local storage which makes them reappear

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when your refresh the page.

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when your refresh the page.

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Smaller Changes

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Smaller Changes

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~~~~~~~~~~~~~~~

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~~~~~~~~~~~~~~~

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- Latex math is supported in widget ``description``\ s

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- Latex math is supported in widget ``description``\ s

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(`#5937 <https://github.com/ipython/ipython/pull/5937>`__).

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(`#5937 <https://github.com/ipython/ipython/pull/5937>`__).

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- Widgets can be display more than once within a single container

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- Widgets can be display more than once within a single container

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widget (`#5963 <https://github.com/ipython/ipython/pull/5963>`__,

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widget (`#5963 <https://github.com/ipython/ipython/pull/5963>`__,

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`#6990 <https://github.com/ipython/ipython/pull/6990>`__).

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`#6990 <https://github.com/ipython/ipython/pull/6990>`__).

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- ``FloatRangeSlider`` and ``IntRangeSlider`` were added

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- ``FloatRangeSlider`` and ``IntRangeSlider`` were added

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(`#6050 <https://github.com/ipython/ipython/pull/6050>`__).

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(`#6050 <https://github.com/ipython/ipython/pull/6050>`__).

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- "Widget" was removed from the ends of all of the widget class names

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- "Widget" was removed from the ends of all of the widget class names

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