extract svg tag from svg files

We expect svg *tags*, not svg *documents*, which have headers, etc.
This lets the SVG DisplayObject extract the svg tag from a document,
so it works with regular svgs from a URL or file.

closes  #700

IPython/core/display.py

@@ -1,407 +1,434 b''
 # -*- coding: utf-8 -*-
 """Top-level display functions for displaying object in different formats.
 
 Authors:
 
 * Brian Granger
 """
 
 #-----------------------------------------------------------------------------
 #       Copyright (C) 2008-2011 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 xml.dom import minidom
+
 from .displaypub import (
     publish_pretty, publish_html,
     publish_latex, publish_svg,
     publish_png, publish_json,
     publish_javascript, publish_jpeg
 )
 
 #-----------------------------------------------------------------------------
 # 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.
     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 string (MIME types) to exclue in the format
         data dict. If this is set all format types will be computed,
         except for those included in this argument.
     """
     include = kwargs.get('include')
     exclude = kwargs.get('exclude')
 
     from IPython.core.interactiveshell import InteractiveShell
     inst = InteractiveShell.instance()
     format = inst.display_formatter.format
     publish = inst.display_pub.publish
 
     for obj in objs:
         format_dict = format(obj, include=include, exclude=exclude)
         publish('IPython.core.display.display', format_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]
     """
     raw = kwargs.pop('raw',False)
     if raw:
         for obj in objs:
             publish_pretty(obj)
     else:
         display(*objs, include=['text/plain'])
 
 
 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]
     """
     raw = kwargs.pop('raw',False)
     if raw:
         for obj in objs:
             publish_html(obj)
     else:
         display(*objs, include=['text/plain','text/html'])
 
 
 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]
     """
     raw = kwargs.pop('raw',False)
     if raw:
         for obj in objs:
             publish_svg(obj)
     else:
         display(*objs, include=['text/plain','image/svg+xml'])
 
 
 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]
     """
     raw = kwargs.pop('raw',False)
     if raw:
         for obj in objs:
             publish_png(obj)
     else:
         display(*objs, include=['text/plain','image/png'])
 
 
 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]
     """
     raw = kwargs.pop('raw',False)
     if raw:
         for obj in objs:
             publish_jpeg(obj)
     else:
         display(*objs, include=['text/plain','image/jpeg'])
 
 
 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]
     """
     raw = kwargs.pop('raw',False)
     if raw:
         for obj in objs:
             publish_latex(obj)
     else:
         display(*objs, include=['text/plain','text/latex'])
 
 
 def display_json(*objs, **kwargs):
     """Display the JSON representation of an object.
 
     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]
     """
     raw = kwargs.pop('raw',False)
     if raw:
         for obj in objs:
             publish_json(obj)
     else:
         display(*objs, include=['text/plain','application/json'])
 
 
 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]
     """
     raw = kwargs.pop('raw',False)
     if raw:
         for obj in objs:
             publish_javascript(obj)
     else:
         display(*objs, include=['text/plain','application/javascript'])
 
 #-----------------------------------------------------------------------------
 # 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 to download 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 data.startswith('http'):
             self.url = data
             self.filename = None
             self.data = None
         else:
             self.data = data
             self.url = url
             self.filename = None if filename is None else unicode(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
 
 
 class Math(DisplayObject):
 
     def _repr_latex_(self):
         return self.data
 
 
 class SVG(DisplayObject):
-
+    
+    # wrap data in a property, which extracts the <svg> tag, discarding
+    # document headers
+    _data = None
+    
+    @property
+    def data(self):
+        return self._data
+    
+    @data.setter
+    def data(self, svg):
+        if svg is None:
+            self._data = None
+            return
+        # parse into dom object
+        x = minidom.parseString(svg)
+        # get svg tag (should be 1)
+        found_svg = x.getElementsByTagName('svg')
+        if found_svg:
+            svg = found_svg[0].toxml()
+        else:
+            # fallback on the input, trust the user
+            # but this is probably an error.
+            pass
+        self._data = svg
+    
     def _repr_svg_(self):
         return self.data
 
 
 class JSON(DisplayObject):
 
     def _repr_json_(self):
         return self.data
 
 
 class Javascript(DisplayObject):
 
     def _repr_javascript_(self):
         return self.data
 
 
 class Image(DisplayObject):
 
     _read_flags = 'rb'
 
     def __init__(self, data=None, url=None, filename=None, format=u'png', embed=False):
         """Create a display an PNG/JPEG image given raw data.
 
         When this object is returned by an expression 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 data or a URL to download the data from.
         url : unicode
             A URL to download the data from.
         filename : unicode
             Path to a local file to load the data from.
         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 in the notebook 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. If a filename is given
             embed is always set to True.
         """
         if filename is not None:
             ext = self._find_ext(filename)
         elif url is not None:
             ext = self._find_ext(url)
         elif data.startswith('http'):
             ext = self._find_ext(data)
         else:
             ext = None
         if ext is not None:
             if ext == u'jpg' or ext == u'jpeg':
                 format = u'jpeg'
             if ext == u'png':
                 format = u'png'
         self.format = unicode(format).lower()
         self.embed = True if filename is not None else embed
         super(Image, self).__init__(data=data, url=url, filename=filename)
 
     def reload(self):
         """Reload the raw data from file or URL."""
         if self.embed:
             super(Image,self).reload()
 
     def _repr_html_(self):
         if not self.embed:
             return u'<img src="%s" />' % self.url
 
     def _repr_png_(self):
         if self.embed and self.format == u'png':
             return self.data
 
     def _repr_jpeg_(self):
         if self.embed and (self.format == u'jpeg' or self.format == u'jpg'):
             return self.data
 
     def _find_ext(self, s):
         return unicode(s.split('.')[-1].lower())
 
 
 def clear_output(stdout=True, stderr=True, other=True):
     """Clear the output of the current cell receiving output.
     
     Optionally, each of stdout/stderr or other non-stream data (e.g. anything
     produced by display()) can be excluded from the clear event.
     
     By default, everything is cleared.
     
     Parameters
     ----------
     stdout : bool [default: True]
         Whether to clear stdout.
     stderr : bool [default: True]
         Whether to clear stderr.
     other : bool [default: True]
         Whether to clear everything else that is not stdout/stderr
         (e.g. figures,images,HTML, any result of display()).
     """
     from IPython.core.interactiveshell import InteractiveShell
     InteractiveShell.instance().display_pub.clear_output(
         stdout=stdout, stderr=stderr, other=other,
     )