Fix style and typo

IPython/core/display.py

@@ -1,708 +1,708 b''
 # -*- coding: utf-8 -*-
 """Top-level display functions for displaying object in different formats.
 
 Authors:
 
 * Brian Granger
 """
 
 #-----------------------------------------------------------------------------
 #       Copyright (C) 2013 The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 from __future__ import print_function
 
 import os
 import struct
 
 from IPython.utils.py3compat import (string_types, cast_bytes_py2, cast_unicode,
                                      unicode_type)
 
 from .displaypub import publish_display_data
 
 #-----------------------------------------------------------------------------
 # utility functions
 #-----------------------------------------------------------------------------
 
 def _safe_exists(path):
     """Check path, but don't let exceptions raise"""
     try:
         return os.path.exists(path)
     except Exception:
         return False
 
 def _merge(d1, d2):
     """Like update, but merges sub-dicts instead of clobbering at the top level.
 
     Updates d1 in-place
     """
 
     if not isinstance(d2, dict) or not isinstance(d1, dict):
         return d2
     for key, value in d2.items():
         d1[key] = _merge(d1.get(key), value)
     return d1
 
 def _display_mimetype(mimetype, objs, raw=False, metadata=None):
     """internal implementation of all display_foo methods
 
     Parameters
     ----------
     mimetype : str
         The mimetype to be published (e.g. 'image/png')
     objs : tuple of objects
         The Python objects to display, or if raw=True raw text data to
         display.
     raw : bool
         Are the data objects raw data or Python objects that need to be
         formatted before display? [default: False]
     metadata : dict (optional)
         Metadata to be associated with the specific mimetype output.
     """
     if metadata:
         metadata = {mimetype: metadata}
     if raw:
         # turn list of pngdata into list of { 'image/png': pngdata }
         objs = [ {mimetype: obj} for obj in objs ]
     display(*objs, raw=raw, metadata=metadata, include=[mimetype])
 
 #-----------------------------------------------------------------------------
 # Main functions
 #-----------------------------------------------------------------------------
 
 def display(*objs, **kwargs):
     """Display a Python object in all frontends.
 
     By default all representations will be computed and sent to the frontends.
     Frontends can decide which representation is used and how.
 
     Parameters
     ----------
     objs : tuple of objects
         The Python objects to display.
     raw : bool, optional
         Are the objects to be displayed already mimetype-keyed dicts of raw display data,
         or Python objects that need to be formatted before display? [default: False]
     include : list or tuple, optional
         A list of format type strings (MIME types) to include in the
         format data dict. If this is set *only* the format types included
         in this list will be computed.
     exclude : list or tuple, optional
         A list of format type strings (MIME types) to exclude in the format
         data dict. If this is set all format types will be computed,
         except for those included in this argument.
     metadata : dict, optional
         A dictionary of metadata to associate with the output.
         mime-type keys in this dictionary will be associated with the individual
         representation formats, if they exist.
     """
     raw = kwargs.get('raw', False)
     include = kwargs.get('include')
     exclude = kwargs.get('exclude')
     metadata = kwargs.get('metadata')
 
     from IPython.core.interactiveshell import InteractiveShell
 
     if raw:
         for obj in objs:
             publish_display_data('display', obj, metadata)
     else:
         format = InteractiveShell.instance().display_formatter.format
         for obj in objs:
             format_dict, md_dict = format(obj, include=include, exclude=exclude)
             if metadata:
                 # kwarg-specified metadata gets precedence
                 _merge(md_dict, metadata)
             publish_display_data('display', format_dict, md_dict)
 
 
 def display_pretty(*objs, **kwargs):
     """Display the pretty (default) representation of an object.
 
     Parameters
     ----------
     objs : tuple of objects
         The Python objects to display, or if raw=True raw text data to
         display.
     raw : bool
         Are the data objects raw data or Python objects that need to be
         formatted before display? [default: False]
     metadata : dict (optional)
         Metadata to be associated with the specific mimetype output.
     """
     _display_mimetype('text/plain', objs, **kwargs)
 
 
 def display_html(*objs, **kwargs):
     """Display the HTML representation of an object.
 
     Parameters
     ----------
     objs : tuple of objects
         The Python objects to display, or if raw=True raw HTML data to
         display.
     raw : bool
         Are the data objects raw data or Python objects that need to be
         formatted before display? [default: False]
     metadata : dict (optional)
         Metadata to be associated with the specific mimetype output.
     """
     _display_mimetype('text/html', objs, **kwargs)
 
 
 def display_svg(*objs, **kwargs):
     """Display the SVG representation of an object.
 
     Parameters
     ----------
     objs : tuple of objects
         The Python objects to display, or if raw=True raw svg data to
         display.
     raw : bool
         Are the data objects raw data or Python objects that need to be
         formatted before display? [default: False]
     metadata : dict (optional)
         Metadata to be associated with the specific mimetype output.
     """
     _display_mimetype('image/svg+xml', objs, **kwargs)
 
 
 def display_png(*objs, **kwargs):
     """Display the PNG representation of an object.
 
     Parameters
     ----------
     objs : tuple of objects
         The Python objects to display, or if raw=True raw png data to
         display.
     raw : bool
         Are the data objects raw data or Python objects that need to be
         formatted before display? [default: False]
     metadata : dict (optional)
         Metadata to be associated with the specific mimetype output.
     """
     _display_mimetype('image/png', objs, **kwargs)
 
 
 def display_jpeg(*objs, **kwargs):
     """Display the JPEG representation of an object.
 
     Parameters
     ----------
     objs : tuple of objects
         The Python objects to display, or if raw=True raw JPEG data to
         display.
     raw : bool
         Are the data objects raw data or Python objects that need to be
         formatted before display? [default: False]
     metadata : dict (optional)
         Metadata to be associated with the specific mimetype output.
     """
     _display_mimetype('image/jpeg', objs, **kwargs)
 
 
 def display_latex(*objs, **kwargs):
     """Display the LaTeX representation of an object.
 
     Parameters
     ----------
     objs : tuple of objects
         The Python objects to display, or if raw=True raw latex data to
         display.
     raw : bool
         Are the data objects raw data or Python objects that need to be
         formatted before display? [default: False]
     metadata : dict (optional)
         Metadata to be associated with the specific mimetype output.
     """
     _display_mimetype('text/latex', objs, **kwargs)
 
 
 def display_json(*objs, **kwargs):
     """Display the JSON representation of an object.
 
     Note that not many frontends support displaying JSON.
 
     Parameters
     ----------
     objs : tuple of objects
         The Python objects to display, or if raw=True raw json data to
         display.
     raw : bool
         Are the data objects raw data or Python objects that need to be
         formatted before display? [default: False]
     metadata : dict (optional)
         Metadata to be associated with the specific mimetype output.
     """
     _display_mimetype('application/json', objs, **kwargs)
 
 
 def display_javascript(*objs, **kwargs):
     """Display the Javascript representation of an object.
 
     Parameters
     ----------
     objs : tuple of objects
         The Python objects to display, or if raw=True raw javascript data to
         display.
     raw : bool
         Are the data objects raw data or Python objects that need to be
         formatted before display? [default: False]
     metadata : dict (optional)
         Metadata to be associated with the specific mimetype output.
     """
     _display_mimetype('application/javascript', objs, **kwargs)
 
 #-----------------------------------------------------------------------------
 # Smart classes
 #-----------------------------------------------------------------------------
 
 
 class DisplayObject(object):
     """An object that wraps data to be displayed."""
 
     _read_flags = 'r'
 
     def __init__(self, data=None, url=None, filename=None):
         """Create a display object given raw data.
 
         When this object is returned by an expression or passed to the
         display function, it will result in the data being displayed
         in the frontend. The MIME type of the data should match the
         subclasses used, so the Png subclass should be used for 'image/png'
         data. If the data is a URL, the data will first be downloaded
         and then displayed. If
 
         Parameters
         ----------
         data : unicode, str or bytes
             The raw data or a URL or file to load the data from
         url : unicode
             A URL to download the data from.
         filename : unicode
             Path to a local file to load the data from.
         """
         if data is not None and isinstance(data, string_types):
             if data.startswith('http') and url is None:
                 url = data
                 filename = None
                 data = None
             elif _safe_exists(data) and filename is None:
                 url = None
                 filename = data
                 data = None
 
         self.data = data
         self.url = url
         self.filename = None if filename is None else unicode_type(filename)
 
         self.reload()
 
     def reload(self):
         """Reload the raw data from file or URL."""
         if self.filename is not None:
             with open(self.filename, self._read_flags) as f:
                 self.data = f.read()
         elif self.url is not None:
             try:
                 import urllib2
                 response = urllib2.urlopen(self.url)
                 self.data = response.read()
                 # extract encoding from header, if there is one:
                 encoding = None
                 for sub in response.headers['content-type'].split(';'):
                     sub = sub.strip()
                     if sub.startswith('charset'):
                         encoding = sub.split('=')[-1].strip()
                         break
                 # decode data, if an encoding was specified
                 if encoding:
                     self.data = self.data.decode(encoding, 'replace')
             except:
                 self.data = None
 
 class Pretty(DisplayObject):
 
     def _repr_pretty_(self):
         return self.data
 
 
 class HTML(DisplayObject):
 
     def _repr_html_(self):
         return self.data
 
     def __html__(self):
         """
         This method exists to inform other HTML-using modules (e.g. Markupsafe,
         htmltag, etc) that this object is HTML and does not need things like
         special characters (<>&) escaped.
         """
         return self._repr_html_()
 
 
 class Math(DisplayObject):
 
     def _repr_latex_(self):
         s = self.data.strip('$')
         return "$$%s$$" % s
 
 
 class Latex(DisplayObject):
 
     def _repr_latex_(self):
         return self.data
 
 
 class SVG(DisplayObject):
 
     def __init__(self, data=None, url=None, filename=None, scoped=False):
         """Create a SVG display object given raw data.
 
         When this object is returned by an expression or passed to the
         display function, it will result in the data being displayed
         in the frontend. If the data is a URL, the data will first be
         downloaded and then displayed.
 
         Parameters
         ----------
         data : unicode, str or bytes
             The Javascript source code or a URL to download it from.
         url : unicode
             A URL to download the data from.
         filename : unicode
             Path to a local file to load the data from.
         scoped : bool
             Should the SVG declarations be scoped.
         """
         if not isinstance(scoped, (bool)):
             raise TypeError('expected bool, got: %r' % scoped)
         self.scoped = scoped
         super(SVG, self).__init__(data=data, url=url, filename=filename)
 
     # wrap data in a property, which extracts the <svg> tag, discarding
     # document headers
     _data = None
 
     @property
     def data(self):
         return self._data
 
     _scoped_class = "ipython-scoped"
 
     @data.setter
     def data(self, svg):
         if svg is None:
             self._data = None
             return
         # parse into dom object
         from xml.dom import minidom
         svg = cast_bytes_py2(svg)
         x = minidom.parseString(svg)
         # get svg tag (should be 1)
         found_svg = x.getElementsByTagName('svg')
         if found_svg:
-            # If the user request scoping, tag the svg with the
+            # If the user requests scoping, tag the svg with the
             # ipython-scoped class
             if self.scoped:
                 classes = (found_svg[0].getAttribute('class') +
                            " " + self._scoped_class)
                 found_svg[0].setAttribute('class', classes)
             svg = found_svg[0].toxml()
         else:
             # fallback on the input, trust the user
             # but this is probably an error.
             pass
         svg = cast_unicode(svg)
         self._data = svg
 
     def _repr_svg_(self):
         return self.data
 
 
 class JSON(DisplayObject):
 
     def _repr_json_(self):
         return self.data
 
 css_t = """$("head").append($("<link/>").attr({
   rel:  "stylesheet",
   type: "text/css",
   href: "%s"
 }));
 """
 
 lib_t1 = """$.getScript("%s", function () {
 """
 lib_t2 = """});
 """
 
 class Javascript(DisplayObject):
 
     def __init__(self, data=None, url=None, filename=None, lib=None, css=None):
         """Create a Javascript display object given raw data.
 
         When this object is returned by an expression or passed to the
         display function, it will result in the data being displayed
         in the frontend. If the data is a URL, the data will first be
         downloaded and then displayed.
 
         In the Notebook, the containing element will be available as `element`,
         and jQuery will be available.  The output area starts hidden, so if
         the js appends content to `element` that should be visible, then
         it must call `container.show()` to unhide the area.
 
         Parameters
         ----------
         data : unicode, str or bytes
             The Javascript source code or a URL to download it from.
         url : unicode
             A URL to download the data from.
         filename : unicode
             Path to a local file to load the data from.
         lib : list or str
             A sequence of Javascript library URLs to load asynchronously before
             running the source code. The full URLs of the libraries should
             be given. A single Javascript library URL can also be given as a
             string.
         css: : list or str
             A sequence of css files to load before running the source code.
             The full URLs of the css files should be given. A single css URL
             can also be given as a string.
         """
         if isinstance(lib, string_types):
             lib = [lib]
         elif lib is None:
             lib = []
         if isinstance(css, string_types):
             css = [css]
         elif css is None:
             css = []
         if not isinstance(lib, (list,tuple)):
             raise TypeError('expected sequence, got: %r' % lib)
         if not isinstance(css, (list,tuple)):
             raise TypeError('expected sequence, got: %r' % css)
         self.lib = lib
         self.css = css
         super(Javascript, self).__init__(data=data, url=url, filename=filename)
 
     def _repr_javascript_(self):
         r = ''
         for c in self.css:
             r += css_t % c
         for l in self.lib:
             r += lib_t1 % l
         r += self.data
         r += lib_t2*len(self.lib)
         return r
 
 # constants for identifying png/jpeg data
 _PNG = b'\x89PNG\r\n\x1a\n'
 _JPEG = b'\xff\xd8'
 
 def _pngxy(data):
     """read the (width, height) from a PNG header"""
     ihdr = data.index(b'IHDR')
     # next 8 bytes are width/height
     w4h4 = data[ihdr+4:ihdr+12]
     return struct.unpack('>ii', w4h4)
 
 def _jpegxy(data):
     """read the (width, height) from a JPEG header"""
     # adapted from http://www.64lines.com/jpeg-width-height
     
     idx = 4
     while True:
         block_size = struct.unpack('>H', data[idx:idx+2])[0]
         idx = idx + block_size
         if data[idx:idx+2] == b'\xFF\xC0':
             # found Start of Frame
             iSOF = idx
             break
         else:
             # read another block
             idx += 2
 
     h, w = struct.unpack('>HH', data[iSOF+5:iSOF+9])
     return w, h
 
 class Image(DisplayObject):
 
     _read_flags = 'rb'
     _FMT_JPEG = u'jpeg'
     _FMT_PNG = u'png'
     _ACCEPTABLE_EMBEDDINGS = [_FMT_JPEG, _FMT_PNG]
 
     def __init__(self, data=None, url=None, filename=None, format=u'png', embed=None, width=None, height=None, retina=False):
         """Create a PNG/JPEG image object given raw data.
 
         When this object is returned by an input cell or passed to the
         display function, it will result in the image being displayed
         in the frontend.
 
         Parameters
         ----------
         data : unicode, str or bytes
             The raw image data or a URL or filename to load the data from.
             This always results in embedded image data.
         url : unicode
             A URL to download the data from. If you specify `url=`,
             the image data will not be embedded unless you also specify `embed=True`.
         filename : unicode
             Path to a local file to load the data from.
             Images from a file are always embedded.
         format : unicode
             The format of the image data (png/jpeg/jpg). If a filename or URL is given
             for format will be inferred from the filename extension.
         embed : bool
             Should the image data be embedded using a data URI (True) or be
             loaded using an <img> tag. Set this to True if you want the image
             to be viewable later with no internet connection in the notebook.
 
             Default is `True`, unless the keyword argument `url` is set, then
             default value is `False`.
 
             Note that QtConsole is not able to display images if `embed` is set to `False`
         width : int
             Width to which to constrain the image in html
         height : int
             Height to which to constrain the image in html
         retina : bool
             Automatically set the width and height to half of the measured
             width and height.
             This only works for embedded images because it reads the width/height
             from image data.
             For non-embedded images, you can just set the desired display width
             and height directly.
 
         Examples
         --------
         # embedded image data, works in qtconsole and notebook
         # when passed positionally, the first arg can be any of raw image data,
         # a URL, or a filename from which to load image data.
         # The result is always embedding image data for inline images.
         Image('http://www.google.fr/images/srpr/logo3w.png')
         Image('/path/to/image.jpg')
         Image(b'RAW_PNG_DATA...')
 
         # Specifying Image(url=...) does not embed the image data,
         # it only generates `<img>` tag with a link to the source.
         # This will not work in the qtconsole or offline.
         Image(url='http://www.google.fr/images/srpr/logo3w.png')
 
         """
         if filename is not None:
             ext = self._find_ext(filename)
         elif url is not None:
             ext = self._find_ext(url)
         elif data is None:
             raise ValueError("No image data found. Expecting filename, url, or data.")
         elif isinstance(data, string_types) and (
             data.startswith('http') or _safe_exists(data)
         ):
             ext = self._find_ext(data)
         else:
             ext = None
 
         if ext is not None:
             format = ext.lower()
             if ext == u'jpg' or ext == u'jpeg':
                 format = self._FMT_JPEG
             if ext == u'png':
                 format = self._FMT_PNG
         elif isinstance(data, bytes) and format == 'png':
             # infer image type from image data header,
             # only if format might not have been specified.
             if data[:2] == _JPEG:
                 format = 'jpeg'
 
         self.format = unicode_type(format).lower()
         self.embed = embed if embed is not None else (url is None)
 
         if self.embed and self.format not in self._ACCEPTABLE_EMBEDDINGS:
             raise ValueError("Cannot embed the '%s' image format" % (self.format))
         self.width = width
         self.height = height
         self.retina = retina
         super(Image, self).__init__(data=data, url=url, filename=filename)
         
         if retina:
             self._retina_shape()
     
     def _retina_shape(self):
         """load pixel-doubled width and height from image data"""
         if not self.embed:
             return
         if self.format == 'png':
             w, h = _pngxy(self.data)
         elif self.format == 'jpeg':
             w, h = _jpegxy(self.data)
         else:
             # retina only supports png
             return
         self.width = w // 2
         self.height = h // 2
 
     def reload(self):
         """Reload the raw data from file or URL."""
         if self.embed:
             super(Image,self).reload()
             if self.retina:
                 self._retina_shape()
 
     def _repr_html_(self):
         if not self.embed:
             width = height = ''
             if self.width:
                 width = ' width="%d"' % self.width
             if self.height:
                 height = ' height="%d"' % self.height
             return u'<img src="%s"%s%s/>' % (self.url, width, height)
 
     def _data_and_metadata(self):
         """shortcut for returning metadata with shape information, if defined"""
         md = {}
         if self.width:
             md['width'] = self.width
         if self.height:
             md['height'] = self.height
         if md:
             return self.data, md
         else:
             return self.data
 
     def _repr_png_(self):
         if self.embed and self.format == u'png':
             return self._data_and_metadata()
 
     def _repr_jpeg_(self):
         if self.embed and (self.format == u'jpeg' or self.format == u'jpg'):
             return self._data_and_metadata()
 
     def _find_ext(self, s):
         return unicode_type(s.split('.')[-1].lower())
 
 
 def clear_output(wait=False):
     """Clear the output of the current cell receiving output.
 
     Parameters
     ----------
     wait : bool [default: false]
         Wait to clear the output until new output is available to replace it."""
     from IPython.core.interactiveshell import InteractiveShell
     if InteractiveShell.initialized():
         InteractiveShell.instance().display_pub.clear_output(wait)
     else:
         from IPython.utils import io
         print('\033[2K\r', file=io.stdout, end='')
         io.stdout.flush()
         print('\033[2K\r', file=io.stderr, end='')
         io.stderr.flush()

IPython/html/static/notebook/js/outputarea.js

@@ -1,712 +1,712 b''
 //----------------------------------------------------------------------------
 //  Copyright (C) 2008 The IPython Development Team
 //
 //  Distributed under the terms of the BSD License.  The full license is in
 //  the file COPYING, distributed as part of this software.
 //----------------------------------------------------------------------------
 
 //============================================================================
 // OutputArea
 //============================================================================
 
 /**
  * @module IPython
  * @namespace IPython
  * @submodule OutputArea
  */
 var IPython = (function (IPython) {
     "use strict";
 
     var utils = IPython.utils;
 
     /**
      * @class OutputArea
      *
      * @constructor
      */
 
     var OutputArea = function (selector, prompt_area) {
         this.selector = selector;
         this.wrapper = $(selector);
         this.outputs = [];
         this.collapsed = false;
         this.scrolled = false;
         this.clear_queued = null;
         if (prompt_area === undefined) {
             this.prompt_area = true;
         } else {
             this.prompt_area = prompt_area;
         }
         this.create_elements();
         this.style();
         this.bind_events();
     };
     
     OutputArea.prototype.create_elements = function () {
         this.element = $("<div/>");
         this.collapse_button = $("<div/>");
         this.prompt_overlay = $("<div/>");
         this.wrapper.append(this.prompt_overlay);
         this.wrapper.append(this.element);
         this.wrapper.append(this.collapse_button);
     };
 
 
     OutputArea.prototype.style = function () {
         this.collapse_button.hide();
         this.prompt_overlay.hide();
         
         this.wrapper.addClass('output_wrapper');
         this.element.addClass('output vbox');
         
         this.collapse_button.addClass("btn output_collapsed");
         this.collapse_button.attr('title', 'click to expand output');
         this.collapse_button.html('. . .');
         
         this.prompt_overlay.addClass('out_prompt_overlay prompt');
         this.prompt_overlay.attr('title', 'click to expand output; double click to hide output');
         
         this.collapse();
     };
 
     /**
      * Should the OutputArea scroll?
      * Returns whether the height (in lines) exceeds a threshold.
      *
      * @private
      * @method _should_scroll
      * @param [lines=100]{Integer}
      * @return {Bool}
      *
      */
     OutputArea.prototype._should_scroll = function (lines) {
         if (lines <=0 ){ return }
         if (!lines) {
             lines = 100;
         }
         // line-height from http://stackoverflow.com/questions/1185151
         var fontSize = this.element.css('font-size');
         var lineHeight = Math.floor(parseInt(fontSize.replace('px','')) * 1.5);
         
         return (this.element.height() > lines * lineHeight);
     };
 
 
     OutputArea.prototype.bind_events = function () {
         var that = this;
         this.prompt_overlay.dblclick(function () { that.toggle_output(); });
         this.prompt_overlay.click(function () { that.toggle_scroll(); });
 
         this.element.resize(function () {
             // FIXME: Firefox on Linux misbehaves, so automatic scrolling is disabled
             if ( IPython.utils.browser[0] === "Firefox" ) {
                 return;
             }
             // maybe scroll output,
             // if it's grown large enough and hasn't already been scrolled.
             if ( !that.scrolled && that._should_scroll(OutputArea.auto_scroll_threshold)) {
                 that.scroll_area();
             }
         });
         this.collapse_button.click(function () {
             that.expand();
         });
     };
 
 
     OutputArea.prototype.collapse = function () {
         if (!this.collapsed) {
             this.element.hide();
             this.prompt_overlay.hide();
             if (this.element.html()){
                 this.collapse_button.show();
             }
             this.collapsed = true;
         }
     };
 
 
     OutputArea.prototype.expand = function () {
         if (this.collapsed) {
             this.collapse_button.hide();
             this.element.show();
             this.prompt_overlay.show();
             this.collapsed = false;
         }
     };
 
 
     OutputArea.prototype.toggle_output = function () {
         if (this.collapsed) {
             this.expand();
         } else {
             this.collapse();
         }
     };
 
 
     OutputArea.prototype.scroll_area = function () {
         this.element.addClass('output_scroll');
         this.prompt_overlay.attr('title', 'click to unscroll output; double click to hide');
         this.scrolled = true;
     };
 
 
     OutputArea.prototype.unscroll_area = function () {
         this.element.removeClass('output_scroll');
         this.prompt_overlay.attr('title', 'click to scroll output; double click to hide');
         this.scrolled = false;
     };
 
     /**
      * Threshold to trigger autoscroll when the OutputArea is resized,
      * typically when new outputs are added.
      *
      * Behavior is undefined if autoscroll is lower than minimum_scroll_threshold,
      * unless it is < 0, in which case autoscroll will never be triggered
      *
      * @property auto_scroll_threshold
      * @type Number
      * @default 100
      *
      **/
     OutputArea.auto_scroll_threshold = 100;
 
 
     /**
      * Lower limit (in lines) for OutputArea to be made scrollable. OutputAreas
      * shorter than this are never scrolled.
      *
      * @property minimum_scroll_threshold
      * @type Number
      * @default 20
      *
      **/
     OutputArea.minimum_scroll_threshold = 20;
 
 
     /**
      *
      * Scroll OutputArea if height supperior than a threshold (in lines).
      *
      * Threshold is a maximum number of lines. If unspecified, defaults to
      * OutputArea.minimum_scroll_threshold.
      *
      * Negative threshold will prevent the OutputArea from ever scrolling.
      *
      * @method scroll_if_long
      *
      * @param [lines=20]{Number} Default to 20 if not set,
      * behavior undefined for value of `0`.
      *
      **/
     OutputArea.prototype.scroll_if_long = function (lines) {
         var n = lines | OutputArea.minimum_scroll_threshold;
         if(n <= 0){
             return
         }
 
         if (this._should_scroll(n)) {
             // only allow scrolling long-enough output
             this.scroll_area();
         }
     };
 
 
     OutputArea.prototype.toggle_scroll = function () {
         if (this.scrolled) {
             this.unscroll_area();
         } else {
             // only allow scrolling long-enough output
             this.scroll_if_long();
         }
     };
 
 
     // typeset with MathJax if MathJax is available
     OutputArea.prototype.typeset = function () {
         if (window.MathJax){
             MathJax.Hub.Queue(["Typeset",MathJax.Hub]);
         }
     };
 
 
     OutputArea.prototype.handle_output = function (msg) {
         var json = {};
         var msg_type = json.output_type = msg.header.msg_type;
         var content = msg.content;
         if (msg_type === "stream") {
             json.text = content.data;
             json.stream = content.name;
         } else if (msg_type === "display_data") {
             json = this.convert_mime_types(json, content.data);
             json.metadata = this.convert_mime_types({}, content.metadata);
         } else if (msg_type === "pyout") {
             json.prompt_number = content.execution_count;
             json = this.convert_mime_types(json, content.data);
             json.metadata = this.convert_mime_types({}, content.metadata);
         } else if (msg_type === "pyerr") {
             json.ename = content.ename;
             json.evalue = content.evalue;
             json.traceback = content.traceback;
         }
         // append with dynamic=true
         this.append_output(json, true);
     };
 
 
     OutputArea.prototype.convert_mime_types = function (json, data) {
         if (data === undefined) {
             return json;
         }
         if (data['text/plain'] !== undefined) {
             json.text = data['text/plain'];
         }
         if (data['text/html'] !== undefined) {
             json.html = data['text/html'];
         }
         if (data['image/svg+xml'] !== undefined) {
             json.svg = data['image/svg+xml'];
         }
         if (data['image/png'] !== undefined) {
             json.png = data['image/png'];
         }
         if (data['image/jpeg'] !== undefined) {
             json.jpeg = data['image/jpeg'];
         }
         if (data['text/latex'] !== undefined) {
             json.latex = data['text/latex'];
         }
         if (data['application/json'] !== undefined) {
             json.json = data['application/json'];
         }
         if (data['application/javascript'] !== undefined) {
             json.javascript = data['application/javascript'];
         }
         return json;
     };
 
 
     OutputArea.prototype.append_output = function (json, dynamic) {
         // If dynamic is true, javascript output will be eval'd.
         this.expand();
 
         // Clear the output if clear is queued.
         var needs_height_reset = false;
         if (this.clear_queued) {
             this.clear_output(false);
             needs_height_reset = true;
         }
 
         if (json.output_type === 'pyout') {
             this.append_pyout(json, dynamic);
         } else if (json.output_type === 'pyerr') {
             this.append_pyerr(json);
         } else if (json.output_type === 'display_data') {
             this.append_display_data(json, dynamic);
         } else if (json.output_type === 'stream') {
             this.append_stream(json);
         }
         this.outputs.push(json);
         
         // Only reset the height to automatic if the height is currently
         // fixed (done by wait=True flag on clear_output).
         if (needs_height_reset) {
             this.element.height('');    
         }
 
         var that = this;
         setTimeout(function(){that.element.trigger('resize');}, 100);
     };
 
 
     OutputArea.prototype.create_output_area = function () {
         var oa = $("<div/>").addClass("output_area");
         if (this.prompt_area) {
             oa.append($('<div/>').addClass('prompt'));
         }
         return oa;
     };
     
     OutputArea.prototype._append_javascript_error = function (err, container) {
         // display a message when a javascript error occurs in display output
         var msg = "Javascript error adding output!"
         console.log(msg, err);
         if ( container === undefined ) return;
         container.append(
             $('<div/>').html(msg + "<br/>" +
                 err.toString() +
                 '<br/>See your browser Javascript console for more details.'
             ).addClass('js-error')
         );
         container.show();
     };
     
     OutputArea.prototype._safe_append = function (toinsert) {
         // safely append an item to the document
         // this is an object created by user code,
         // and may have errors, which should not be raised
         // under any circumstances.
         try {
             this.element.append(toinsert);
         } catch(err) {
             console.log(err);
             this._append_javascript_error(err, this.element);
         }
     };
 
 
     OutputArea.prototype.append_pyout = function (json, dynamic) {
         var n = json.prompt_number || ' ';
         var toinsert = this.create_output_area();
         if (this.prompt_area) {
             toinsert.find('div.prompt').addClass('output_prompt').html('Out[' + n + ']:');
         }
         this.append_mime_type(json, toinsert, dynamic);
         this._safe_append(toinsert);
         // If we just output latex, typeset it.
         if ((json.latex !== undefined) || (json.html !== undefined)) {
             this.typeset();
         }
     };
 
 
     OutputArea.prototype.append_pyerr = function (json) {
         var tb = json.traceback;
         if (tb !== undefined && tb.length > 0) {
             var s = '';
             var len = tb.length;
             for (var i=0; i<len; i++) {
                 s = s + tb[i] + '\n';
             }
             s = s + '\n';
             var toinsert = this.create_output_area();
             this.append_text(s, {}, toinsert);
             this._safe_append(toinsert);
         }
     };
 
 
     OutputArea.prototype.append_stream = function (json) {
         // temporary fix: if stream undefined (json file written prior to this patch),
         // default to most likely stdout:
         if (json.stream == undefined){
             json.stream = 'stdout';
         }
         var text = json.text;
         var subclass = "output_"+json.stream;
         if (this.outputs.length > 0){
             // have at least one output to consider
             var last = this.outputs[this.outputs.length-1];
             if (last.output_type == 'stream' && json.stream == last.stream){
                 // latest output was in the same stream,
                 // so append directly into its pre tag
                 // escape ANSI & HTML specials:
                 var pre = this.element.find('div.'+subclass).last().find('pre');
                 var html = utils.fixCarriageReturn(
                     pre.html() + utils.fixConsole(text));
                 pre.html(html);
                 return;
             }
         }
 
         if (!text.replace("\r", "")) {
             // text is nothing (empty string, \r, etc.)
             // so don't append any elements, which might add undesirable space
             return;
         }
 
         // If we got here, attach a new div
         var toinsert = this.create_output_area();
         this.append_text(text, {}, toinsert, "output_stream "+subclass);
         this._safe_append(toinsert);
     };
 
 
     OutputArea.prototype.append_display_data = function (json, dynamic) {
         var toinsert = this.create_output_area();
         this.append_mime_type(json, toinsert, dynamic);
         this._safe_append(toinsert);
         // If we just output latex, typeset it.
         if ( (json.latex !== undefined) || (json.html !== undefined) ) {
             this.typeset();
         }
     };
 
     OutputArea.display_order = ['javascript','html','latex','svg','png','jpeg','text'];
 
     OutputArea.prototype.append_mime_type = function (json, element, dynamic) {
         for(var type_i in OutputArea.display_order){
             var type = OutputArea.display_order[type_i];
             if(json[type] != undefined ){
                 var md = {};
                 if (json.metadata && json.metadata[type]) {
                     md = json.metadata[type];
                 };
                 if(type == 'javascript'){
                     if (dynamic) {
                         this.append_javascript(json.javascript, md, element, dynamic);
                     }
                 } else {
                     this['append_'+type](json[type], md, element);
                 }
                 return;
             }
         }
     };
 
 
     OutputArea.prototype.append_html = function (html, md, element) {
         var toinsert = $("<div/>").addClass("output_subarea output_html rendered_html");
         toinsert.append(html);
         element.append(toinsert);
     };
 
 
     OutputArea.prototype.append_javascript = function (js, md, container) {
         // We just eval the JS code, element appears in the local scope.
         var element = $("<div/>").addClass("output_subarea");
         container.append(element);
         // Div for js shouldn't be drawn, as it will add empty height to the area.
         container.hide();
         // If the Javascript appends content to `element` that should be drawn, then
         // it must also call `container.show()`.
         try {
             eval(js);
         } catch(err) {
             this._append_javascript_error(err, container);
         }
     };
 
 
     OutputArea.prototype.append_text = function (data, md, element, extra_class) {
         var toinsert = $("<div/>").addClass("output_subarea output_text");
         // escape ANSI & HTML specials in plaintext:
         data = utils.fixConsole(data);
         data = utils.fixCarriageReturn(data);
         data = utils.autoLinkUrls(data);
         if (extra_class){
             toinsert.addClass(extra_class);
         }
         toinsert.append($("<pre/>").html(data));
         element.append(toinsert);
     };
 
 
     OutputArea.prototype.append_svg = function (svg, md, element) {
         var wrapper = $('<div/>').addClass('output_subarea output_svg');
         wrapper.append(svg);
         var svg_element = wrapper.children()[0];
 
         if (svg_element.classList.contains('ipython-scoped')) {
             // To avoid style or use collisions between multiple svg figures,
             // svg figures are wrapped inside an iframe.
             var iframe = $('<iframe/>')
-                iframe.attr('frameborder', 0);
+            iframe.attr('frameborder', 0);
             iframe.attr('scrolling', 'no');
 
             // Once the iframe is loaded, the svg is dynamically inserted
             iframe.on('load', function() {
                 // Set the iframe height and width to fit the svg
                 // (the +10 pixel offset handles the default body margins
                 // in Chrome)
                 iframe.width(svg_element.width.baseVal.value + 10);
                 iframe.height(svg_element.height.baseVal.value + 10);
 
                 // Workaround needed by Firefox, to properly render svg inside
                 // iframes, see http://stackoverflow.com/questions/10177190/
                 // svg-dynamically-added-to-iframe-does-not-render-correctly
                 iframe.contents()[0].open();
                 iframe.contents()[0].close();
 
                 // Insert the svg inside the iframe
                 var body = iframe.contents().find('body');
                 body.html(wrapper.html());
             });
 
             element.append(iframe);
         } else {
             element.append(wrapper);
         }
     };
 
 
     OutputArea.prototype._dblclick_to_reset_size = function (img) {
         // schedule wrapping image in resizable after a delay,
         // so we don't end up calling resize on a zero-size object
         var that = this;
         setTimeout(function () {
             var h0 = img.height();
             var w0 = img.width();
             if (!(h0 && w0)) {
                 // zero size, schedule another timeout
                 that._dblclick_to_reset_size(img);
                 return;
             }
             img.resizable({
                 aspectRatio: true,
                 autoHide: true
             });
             img.dblclick(function () {
                 // resize wrapper & image together for some reason:
                 img.parent().height(h0);
                 img.height(h0);
                 img.parent().width(w0);
                 img.width(w0);
             });
         }, 250);
     };
 
 
     OutputArea.prototype.append_png = function (png, md, element) {
         var toinsert = $("<div/>").addClass("output_subarea output_png");
         var img = $("<img/>").attr('src','data:image/png;base64,'+png);
         if (md['height']) {
             img.attr('height', md['height']);
         }
         if (md['width']) {
             img.attr('width', md['width']);
         }
         this._dblclick_to_reset_size(img);
         toinsert.append(img);
         element.append(toinsert);
     };
 
 
     OutputArea.prototype.append_jpeg = function (jpeg, md, element) {
         var toinsert = $("<div/>").addClass("output_subarea output_jpeg");
         var img = $("<img/>").attr('src','data:image/jpeg;base64,'+jpeg);
         if (md['height']) {
             img.attr('height', md['height']);
         }
         if (md['width']) {
             img.attr('width', md['width']);
         }
         this._dblclick_to_reset_size(img);
         toinsert.append(img);
         element.append(toinsert);
     };
 
 
     OutputArea.prototype.append_latex = function (latex, md, element) {
         // This method cannot do the typesetting because the latex first has to
         // be on the page.
         var toinsert = $("<div/>").addClass("output_subarea output_latex");
         toinsert.append(latex);
         element.append(toinsert);
     };
 
     OutputArea.prototype.append_raw_input = function (msg) {
         var that = this;
         this.expand();
         var content = msg.content;
         var area = this.create_output_area();
         
         // disable any other raw_inputs, if they are left around
         $("div.output_subarea.raw_input").remove();
         
         area.append(
             $("<div/>")
             .addClass("box-flex1 output_subarea raw_input")
             .append(
                 $("<span/>")
                 .addClass("input_prompt")
                 .text(content.prompt)
             )
             .append(
                 $("<input/>")
                 .addClass("raw_input")
                 .attr('type', 'text')
                 .attr("size", 47)
                 .keydown(function (event, ui) {
                     // make sure we submit on enter,
                     // and don't re-execute the *cell* on shift-enter
                     if (event.which === utils.keycodes.ENTER) {
                         that._submit_raw_input();
                         return false;
                     }
                 })
             )
         );
         this.element.append(area);
         // weirdly need double-focus now,
         // otherwise only the cell will be focused
         area.find("input.raw_input").focus().focus();
     }
     OutputArea.prototype._submit_raw_input = function (evt) {
         var container = this.element.find("div.raw_input");
         var theprompt = container.find("span.input_prompt");
         var theinput = container.find("input.raw_input");
         var value = theinput.val();
         var content = {
             output_type : 'stream',
             name : 'stdout',
             text : theprompt.text() + value + '\n'
         }
         // remove form container
         container.parent().remove();
         // replace with plaintext version in stdout
         this.append_output(content, false);
         $([IPython.events]).trigger('send_input_reply.Kernel', value);
     }
 
 
     OutputArea.prototype.handle_clear_output = function (msg) {
         this.clear_output(msg.content.wait);
     };
 
 
     OutputArea.prototype.clear_output = function(wait) {
         if (wait) {
 
             // If a clear is queued, clear before adding another to the queue.
             if (this.clear_queued) {
                 this.clear_output(false);
             };
 
             this.clear_queued = true;
         } else {
 
             // Fix the output div's height if the clear_output is waiting for
             // new output (it is being used in an animation).
             if (this.clear_queued) {
                 var height = this.element.height();
                 this.element.height(height);
                 this.clear_queued = false;
             }
             
             // clear all, no need for logic
             this.element.html("");
             this.outputs = [];
             this.unscroll_area();
             return;
         };
     };
 
 
     // JSON serialization
 
     OutputArea.prototype.fromJSON = function (outputs) {
         var len = outputs.length;
         for (var i=0; i<len; i++) {
             // append with dynamic=false.
             this.append_output(outputs[i], false);
         }
     };
 
 
     OutputArea.prototype.toJSON = function () {
         var outputs = [];
         var len = this.outputs.length;
         for (var i=0; i<len; i++) {
             outputs[i] = this.outputs[i];
         }
         return outputs;
     };
 
 
     IPython.OutputArea = OutputArea;
 
     return IPython;
 
 }(IPython));