display.py

"""Various display related classes.

Authors : MinRK, gregcaporaso, dannystaple
"""
from os.path import exists, isfile, splitext, abspath, join, isdir
from os import walk, sep

from IPython.core.display import DisplayObject

__all__ = ['Audio', 'IFrame', 'YouTubeVideo', 'VimeoVideo', 'ScribdDocument',
           'FileLink', 'FileLinks']


class Audio(DisplayObject):
    """Create an audio object.

    When this object is returned by an input cell or passed to the
    display function, it will result in Audio controls being displayed
    in the frontend (only works in the notebook).

    Parameters
    ----------
    data : numpy array, list, unicode, str or bytes
        Can be one of

          * Numpy 1d array containing the desired waveform (mono)
          * Numpy 2d array containing waveforms for each channel.
            Shape=(NCHAN, NSAMPLES). For the standard channel order, see
            http://msdn.microsoft.com/en-us/library/windows/hardware/dn653308(v=vs.85).aspx
          * List of float or integer representing the waveform (mono)
          * String containing the filename
          * Bytestring containing raw PCM data or
          * URL pointing to a file on the web.

        If the array option is used the waveform will be normalized.

        If a filename or url is used the format support will be browser
        dependent.
    url : unicode
        A URL to download the data from.
    filename : unicode
        Path to a local file to load the data from.
    embed : boolean
        Should the image data be embedded using a data URI (True) or should
        the original source be referenced. Set this to True if you want the
        audio to playable later with no internet connection in the notebook.

        Default is `True`, unless the keyword argument `url` is set, then
        default value is `False`.
    rate : integer
        The sampling rate of the raw data.
        Only required when data parameter is being used as an array
    autoplay : bool
        Set to True if the audio should immediately start playing.
        Default is `False`.

    Examples
    --------
    ::

        # Generate a sound
        import numpy as np
        framerate = 44100
        t = np.linspace(0,5,framerate*5)
        data = np.sin(2*np.pi*220*t) + np.sin(2*np.pi*224*t))
        Audio(data,rate=framerate)

        # Can also do stereo or more channels
        dataleft = np.sin(2*np.pi*220*t)
        dataright = np.sin(2*np.pi*224*t)
        Audio([dataleft, dataright],rate=framerate)

        Audio("http://www.nch.com.au/acm/8k16bitpcm.wav")  # From URL
        Audio(url="http://www.w3schools.com/html/horse.ogg")

        Audio('/path/to/sound.wav')  # From file
        Audio(filename='/path/to/sound.ogg')

        Audio(b'RAW_WAV_DATA..)  # From bytes
        Audio(data=b'RAW_WAV_DATA..)

    """
    _read_flags = 'rb'

    def __init__(self, data=None, filename=None, url=None, embed=None, rate=None, autoplay=False):
        if filename is None and url is None and data is None:
            raise ValueError("No image data found. Expecting filename, url, or data.")
        if embed is False and url is None:
            raise ValueError("No url found. Expecting url when embed=False")

        if url is not None and embed is not True:
            self.embed = False
        else:
            self.embed = True
        self.autoplay = autoplay
        super(Audio, self).__init__(data=data, url=url, filename=filename)

        if self.data is not None and not isinstance(self.data, bytes):
            self.data = self._make_wav(data,rate)

    def reload(self):
        """Reload the raw data from file or URL."""
        import mimetypes
        if self.embed:
            super(Audio, self).reload()

        if self.filename is not None:
            self.mimetype = mimetypes.guess_type(self.filename)[0]
        elif self.url is not None:
            self.mimetype = mimetypes.guess_type(self.url)[0]
        else:
            self.mimetype = "audio/wav"

    def _make_wav(self, data, rate):
        """ Transform a numpy array to a PCM bytestring """
        import struct
        from io import BytesIO
        import wave

        try:
            import numpy as np

            data = np.array(data, dtype=float)
            if len(data.shape) == 1:
                nchan = 1
            elif len(data.shape) == 2:
                # In wave files,channels are interleaved. E.g.,
                # "L1R1L2R2..." for stereo. See
                # http://msdn.microsoft.com/en-us/library/windows/hardware/dn653308(v=vs.85).aspx
                # for channel ordering
                nchan = data.shape[0]
                data = data.T.ravel()
            else:
                raise ValueError('Array audio input must be a 1D or 2D array')
            scaled = np.int16(data/np.max(np.abs(data))*32767).tolist()
        except ImportError:
            # check that it is a "1D" list
            idata = iter(data)  # fails if not an iterable
            try:
                iter(idata.next())
                raise TypeError('Only lists of mono audio are '
                    'supported if numpy is not installed')
            except TypeError:
                # this means it's not a nested list, which is what we want
                pass
            maxabsvalue = float(max([abs(x) for x in data]))
            scaled = [int(x/maxabsvalue*32767) for x in data]
            nchan = 1

        fp = BytesIO()
        waveobj = wave.open(fp,mode='wb')
        waveobj.setnchannels(nchan)
        waveobj.setframerate(rate)
        waveobj.setsampwidth(2)
        waveobj.setcomptype('NONE','NONE')
        waveobj.writeframes(b''.join([struct.pack('<h',x) for x in scaled]))
        val = fp.getvalue()
        waveobj.close()

        return val

    def _data_and_metadata(self):
        """shortcut for returning metadata with url information, if defined"""
        md = {}
        if self.url:
            md['url'] = self.url
        if md:
            return self.data, md
        else:
            return self.data

    def _repr_html_(self):
        src = """
                <audio controls="controls" {autoplay}>
                    <source src="{src}" type="{type}" />
                    Your browser does not support the audio element.
                </audio>
              """
        return src.format(src=self.src_attr(),type=self.mimetype, autoplay=self.autoplay_attr())

    def src_attr(self):
        import base64
        if self.embed and (self.data is not None):
            data = base64=base64.b64encode(self.data).decode('ascii')
            return """data:{type};base64,{base64}""".format(type=self.mimetype,
                                                            base64=data)
        elif self.url is not None:
            return self.url
        else:
            return ""

    def autoplay_attr(self):
        if(self.autoplay):
            return 'autoplay="autoplay"'
        else:
            return ''

class IFrame(object):
    """
    Generic class to embed an iframe in an IPython notebook
    """

    iframe = """
        <iframe
            width="{width}"
            height={height}"
            src="{src}{params}"
            frameborder="0"
            allowfullscreen
        ></iframe>
        """

    def __init__(self, src, width, height, **kwargs):
        self.src = src
        self.width = width
        self.height = height
        self.params = kwargs

    def _repr_html_(self):
        """return the embed iframe"""
        if self.params:
            try:
                from urllib.parse import urlencode # Py 3
            except ImportError:
                from urllib import urlencode
            params = "?" + urlencode(self.params)
        else:
            params = ""
        return self.iframe.format(src=self.src,
                                  width=self.width,
                                  height=self.height,
                                  params=params)

class YouTubeVideo(IFrame):
    """Class for embedding a YouTube Video in an IPython session, based on its video id.

    e.g. to embed the video from https://www.youtube.com/watch?v=foo , you would
    do::

        vid = YouTubeVideo("foo")
        display(vid)

    To start from 30 seconds::

        vid = YouTubeVideo("abc", start=30)
        display(vid)

    To calculate seconds from time as hours, minutes, seconds use
    :class:`datetime.timedelta`::

        start=int(timedelta(hours=1, minutes=46, seconds=40).total_seconds())

    Other parameters can be provided as documented at
    https://developers.google.com/youtube/player_parameters#parameter-subheader
    """

    def __init__(self, id, width=400, height=300, **kwargs):
        src = "https://www.youtube.com/embed/{0}".format(id)
        super(YouTubeVideo, self).__init__(src, width, height, **kwargs)

class VimeoVideo(IFrame):
    """
    Class for embedding a Vimeo video in an IPython session, based on its video id.
    """

    def __init__(self, id, width=400, height=300, **kwargs):
        src="https://player.vimeo.com/video/{0}".format(id)
        super(VimeoVideo, self).__init__(src, width, height, **kwargs)

class ScribdDocument(IFrame):
    """
    Class for embedding a Scribd document in an IPython session

    Use the start_page params to specify a starting point in the document
    Use the view_mode params to specify display type one off scroll | slideshow | book

    e.g to Display Wes' foundational paper about PANDAS in book mode from page 3

    ScribdDocument(71048089, width=800, height=400, start_page=3, view_mode="book")
    """

    def __init__(self, id, width=400, height=300, **kwargs):
        src="https://www.scribd.com/embeds/{0}/content".format(id)
        super(ScribdDocument, self).__init__(src, width, height, **kwargs)

class FileLink(object):
    """Class for embedding a local file link in an IPython session, based on path

    e.g. to embed a link that was generated in the IPython notebook as my/data.txt

    you would do::

        local_file = FileLink("my/data.txt")
        display(local_file)

    or in the HTML notebook, just::

        FileLink("my/data.txt")
    """

    html_link_str = "<a href='%s' target='_blank'>%s</a>"

    def __init__(self,
                 path,
                 url_prefix='',
                 result_html_prefix='',
                 result_html_suffix='<br>'):
        """
        Parameters
        ----------
        path : str
            path to the file or directory that should be formatted
        directory_prefix : str
            prefix to be prepended to all files to form a working link [default:
            'files']
        result_html_prefix : str
            text to append to beginning to link [default: none]
        result_html_suffix : str
            text to append at the end of link [default: '<br>']
        """
        if isdir(path):
            raise ValueError("Cannot display a directory using FileLink. "
              "Use FileLinks to display '%s'." % path)
        self.path = path
        self.url_prefix = url_prefix
        self.result_html_prefix = result_html_prefix
        self.result_html_suffix = result_html_suffix

    def _format_path(self):
        fp = ''.join([self.url_prefix,self.path])
        return ''.join([self.result_html_prefix,
                        self.html_link_str % (fp, self.path),
                        self.result_html_suffix])

    def _repr_html_(self):
        """return html link to file
        """
        if not exists(self.path):
            return ("Path (<tt>%s</tt>) doesn't exist. "
                    "It may still be in the process of "
                    "being generated, or you may have the "
                    "incorrect path." % self.path)

        return self._format_path()

    def __repr__(self):
        """return absolute path to file
        """
        return abspath(self.path)

class FileLinks(FileLink):
    """Class for embedding local file links in an IPython session, based on path

    e.g. to embed links to files that were generated in the IPython notebook
    under ``my/data``, you would do::

        local_files = FileLinks("my/data")
        display(local_files)

    or in the HTML notebook, just::

        FileLinks("my/data")
    """
    def __init__(self,
                 path,
                 url_prefix='',
                 included_suffixes=None,
                 result_html_prefix='',
                 result_html_suffix='<br>',
                 notebook_display_formatter=None,
                 terminal_display_formatter=None):
        """
        See :class:`FileLink` for the ``path``, ``url_prefix``,
        ``result_html_prefix`` and ``result_html_suffix`` parameters.

        included_suffixes : list
          Filename suffixes to include when formatting output [default: include
          all files]

        notebook_display_formatter : function
          Used to format links for display in the notebook. See discussion of
          formatter functions below.

        terminal_display_formatter : function
          Used to format links for display in the terminal. See discussion of
          formatter functions below.

        Formatter functions must be of the form::

            f(dirname, fnames, included_suffixes)

        dirname : str
          The name of a directory
        fnames : list
          The files in that directory
        included_suffixes : list
          The file suffixes that should be included in the output (passing None
          meansto include all suffixes in the output in the built-in formatters)

        The function should return a list of lines that will be printed in the
        notebook (if passing notebook_display_formatter) or the terminal (if
        passing terminal_display_formatter). This function is iterated over for
        each directory in self.path. Default formatters are in place, can be
        passed here to support alternative formatting.

        """
        if isfile(path):
            raise ValueError("Cannot display a file using FileLinks. "
              "Use FileLink to display '%s'." % path)
        self.included_suffixes = included_suffixes
        # remove trailing slashs for more consistent output formatting
        path = path.rstrip('/')

        self.path = path
        self.url_prefix = url_prefix
        self.result_html_prefix = result_html_prefix
        self.result_html_suffix = result_html_suffix

        self.notebook_display_formatter = \
             notebook_display_formatter or self._get_notebook_display_formatter()
        self.terminal_display_formatter = \
             terminal_display_formatter or self._get_terminal_display_formatter()

    def _get_display_formatter(self,
                               dirname_output_format,
                               fname_output_format,
                               fp_format,
                               fp_cleaner=None):
        """ generate built-in formatter function

           this is used to define both the notebook and terminal built-in
            formatters as they only differ by some wrapper text for each entry

           dirname_output_format: string to use for formatting directory
            names, dirname will be substituted for a single "%s" which
            must appear in this string
           fname_output_format: string to use for formatting file names,
            if a single "%s" appears in the string, fname will be substituted
            if two "%s" appear in the string, the path to fname will be
             substituted for the first and fname will be substituted for the
             second
           fp_format: string to use for formatting filepaths, must contain
            exactly two "%s" and the dirname will be subsituted for the first
            and fname will be substituted for the second
        """
        def f(dirname, fnames, included_suffixes=None):
            result = []
            # begin by figuring out which filenames, if any,
            # are going to be displayed
            display_fnames = []
            for fname in fnames:
                if (isfile(join(dirname,fname)) and
                       (included_suffixes == None or
                        splitext(fname)[1] in included_suffixes)):
                      display_fnames.append(fname)

            if len(display_fnames) == 0:
                # if there are no filenames to display, don't print anything
                # (not even the directory name)
                pass
            else:
                # otherwise print the formatted directory name followed by
                # the formatted filenames
                dirname_output_line = dirname_output_format % dirname
                result.append(dirname_output_line)
                for fname in display_fnames:
                    fp = fp_format % (dirname,fname)
                    if fp_cleaner is not None:
                        fp = fp_cleaner(fp)
                    try:
                        # output can include both a filepath and a filename...
                        fname_output_line = fname_output_format % (fp, fname)
                    except TypeError:
                        # ... or just a single filepath
                        fname_output_line = fname_output_format % fname
                    result.append(fname_output_line)
            return result
        return f

    def _get_notebook_display_formatter(self,
                                        spacer="&nbsp;&nbsp;"):
        """ generate function to use for notebook formatting
        """
        dirname_output_format = \
         self.result_html_prefix + "%s/" + self.result_html_suffix
        fname_output_format = \
         self.result_html_prefix + spacer + self.html_link_str + self.result_html_suffix
        fp_format = self.url_prefix + '%s/%s'
        if sep == "\\":
            # Working on a platform where the path separator is "\", so
            # must convert these to "/" for generating a URI
            def fp_cleaner(fp):
                # Replace all occurences of backslash ("\") with a forward
                # slash ("/") - this is necessary on windows when a path is
                # provided as input, but we must link to a URI
                return fp.replace('\\','/')
        else:
            fp_cleaner = None

        return self._get_display_formatter(dirname_output_format,
                                           fname_output_format,
                                           fp_format,
                                           fp_cleaner)

    def _get_terminal_display_formatter(self,
                                        spacer="  "):
        """ generate function to use for terminal formatting
        """
        dirname_output_format = "%s/"
        fname_output_format = spacer + "%s"
        fp_format = '%s/%s'

        return self._get_display_formatter(dirname_output_format,
                                           fname_output_format,
                                           fp_format)

    def _format_path(self):
        result_lines = []
        walked_dir = list(walk(self.path))
        walked_dir.sort()
        for dirname, subdirs, fnames in walked_dir:
            result_lines += self.notebook_display_formatter(dirname, fnames, self.included_suffixes)
        return '\n'.join(result_lines)

    def __repr__(self):
        """return newline-separated absolute paths
        """
        result_lines = []
        walked_dir = list(walk(self.path))
        walked_dir.sort()
        for dirname, subdirs, fnames in walked_dir:
            result_lines += self.terminal_display_formatter(dirname, fnames, self.included_suffixes)
        return '\n'.join(result_lines)