text: """
  Contains Image panes including renderers for PNG, SVG, GIF and JPG
  file types.
  """
  import base64
  
  from io import BytesIO
  from six import string_types
  
  import param
  
  from .markup import escape, DivPaneBase
  from ..util import isfile, isurl
  
  
  class ImageBase(DivPaneBase):
      """
      Encodes an image as base64 and wraps it in a Bokeh Div model.
      This is an abstract base class that needs the image type
      to be specified and specific code for determining the image shape.
  
      The imgtype determines the filetype, extension, and MIME type for
      this image. Each image type (png,jpg,gif) has a base class that
      supports anything with a `_repr_X_` method (where X is `png`,
      `gif`, etc.), a local file with the given file extension, or a
      HTTP(S) url with the given extension.  Subclasses of each type can
      provide their own way of obtaining or generating a PNG.
      """
  
      alt_text = param.String(default=None, doc="""
          alt text to add to the image tag. The alt text is shown when a
          user cannot load or display the image.""")
  
      link_url = param.String(default=None, doc="""
          A link URL to make the image clickable and link to some other
          website.""")
  
      embed = param.Boolean(default=True, doc="""
          Whether to embed the image as base64.""")
  
      imgtype = 'None'
  
      _rerender_params = ['alt_text', 'link_url', 'embed', 'object', 'style', 'width', 'height']
  
      _target_transforms = {'object': """'<img src="' + value + '"></img>'"""}
  
      __abstract = True
  
      @classmethod
      def applies(cls, obj):
          imgtype = cls.imgtype
          if hasattr(obj, '_repr_{}_'.format(imgtype)):
              return True
          if isinstance(obj, string_types):
              if isfile(obj) and obj.endswith('.'+imgtype):
                  return True
              if isurl(obj, [cls.imgtype]):
                  return True
              elif isurl(obj, None):
                  return 0
          if hasattr(obj, 'read'):  # Check for file like object
              return True
          return False
  
      def _type_error(self, object):
          if isinstance(object, string_types):
              raise ValueError("%s pane cannot parse string that is not a filename "
                               "or URL." % type(self).__name__)
          super()._type_error(object)
  
      def _img(self):
          if hasattr(self.object, '_repr_{}_'.format(self.imgtype)):
              return getattr(self.object, '_repr_' + self.imgtype + '_')()
          if isinstance(self.object, string_types):
              if isfile(self.object):
                  with open(self.object, 'rb') as f:
                      return f.read()
          if hasattr(self.object, 'read'):
              if hasattr(self.object, 'seek'):
                  self.object.seek(0)
              return self.object.read()
          if isurl(self.object, None):
              import requests
              r = requests.request(url=self.object, method='GET')
              return r.content
  
      def _b64(self):
          data = self._img()
          if not isinstance(data, bytes):
              data = data.encode('utf-8')
          b64 = base64.b64encode(data).decode("utf-8")
          return "data:image/"+self.imgtype+f";base64,{b64}"
  
      def _imgshape(self, data):
          """Calculate and return image width,height"""
          raise NotImplementedError
  
      def _get_properties(self):
          p = super()._get_properties()
          if self.object is None:
              return dict(p, text='<img></img>')
          data = self._img()
          if not isinstance(data, bytes):
              data = base64.b64decode(data)
          width, height = self._imgshape(data)
          if self.width is not None:
              if self.height is None:
                  height = int((self.width/width)*height)
              else:
                  height = self.height
              width = self.width
          elif self.height is not None:
              width = int((self.height/height)*width)
              height = self.height
          if not self.embed:
              src = self.object
          else:
              b64 = base64.b64encode(data).decode("utf-8")
              src = "data:image/"+self.imgtype+";base64,{b64}".format(b64=b64)
  
          smode = self.sizing_mode
          if smode in ['fixed', None]:
              w, h = '%spx' % width, '%spx' % height
          elif smode == 'stretch_both':
              w, h = '100%', '100%'
          elif smode == 'stretch_width':
              w, h = '%spx' % width, '100%'
          elif smode == 'stretch_height':
              w, h = '100%', '%spx' % height
          elif smode == 'scale_height':
              w, h = 'auto', '100%'
          else:
              w, h = '100%', 'auto'
  
          html = '<img src="{src}" width="{width}" height="{height}" alt="{alt}"></img>'.format(
              src=src, width=w, height=h, alt=self.alt_text or '')
  
          if self.link_url:
              html = '<a href="{url}" target="_blank">{html}</a>'.format(
                  url=self.link_url, html=html)
  
          return dict(p, width=width, height=height, text=escape(html))
  
  
  class PNG(ImageBase):
  
      imgtype = 'png'
  
      @classmethod
      def _imgshape(cls, data):
          import struct
          w, h = struct.unpack('>LL', data[16:24])
          return int(w), int(h)
  
  
  class GIF(ImageBase):
  
      imgtype = 'gif'
  
      @classmethod
      def _imgshape(cls, data):
          import struct
          w, h = struct.unpack("<HH", data[6:10])
          return int(w), int(h)
  
  
  class JPG(ImageBase):
  
      imgtype = 'jpg'
  
      @classmethod
      def _imgshape(cls, data):
          import struct
          b = BytesIO(data)
          b.read(2)
          c = b.read(1)
          while (c and ord(c) != 0xDA):
              while (ord(c) != 0xFF): c = b.read(1)
              while (ord(c) == 0xFF): c = b.read(1)
              if (ord(c) >= 0xC0 and ord(c) <= 0xC3):
                  b.read(3)
                  h, w = struct.unpack(">HH", b.read(4))
                  break
              else:
                  b.read(int(struct.unpack(">H", b.read(2))[0])-2)
              c = b.read(1)
          return int(w), int(h)
  
  
  class SVG(ImageBase):
  
      encode = param.Boolean(default=False, doc="""
          Whether to enable base64 encoding of the SVG, base64 encoded
          SVGs do not support links.""")
  
      imgtype = 'svg'
  
      _rerender_params = ImageBase._rerender_params + ['encode']
  
      @classmethod
      def applies(cls, obj):
          return (super().applies(obj) or
                  (isinstance(obj, string_types) and obj.lstrip().startswith('<svg')))
  
      def _type_error(self, object):
          if isinstance(object, string_types):
              raise ValueError("%s pane cannot parse string that is not a filename, "
                               "URL or a SVG XML contents." % type(self).__name__)
          super()._type_error(object)
  
      def _img(self):
          if (isinstance(self.object, string_types) and
              self.object.lstrip().startswith('<svg')):
              return self.object
          return super()._img()
  
      def _b64(self):
          data = self._img()
          if not isinstance(data, bytes):
              data = data.encode('utf-8')
          b64 = base64.b64encode(data).decode("utf-8")
          return f"data:image/svg+xml;base64,{b64}"
  
      def _imgshape(self, data):
          return (self.width, self.height)
  
      def _get_properties(self):
          p = super(ImageBase, self)._get_properties()
          if self.object is None:
              return dict(p, text='<img></img>')
          data = self._img()
          width, height = self._imgshape(data)
          if not isinstance(data, bytes):
              data = data.encode('utf-8')
  
          if self.encode:
              b64 = base64.b64encode(data).decode("utf-8")
              src = "data:image/svg+xml;base64,{b64}".format(b64=b64)
              html = "<img src='{src}' width={width} height={height}></img>".format(
                  src=src, width=width, height=height
              )
          else:
              html = data.decode("utf-8")
          return dict(p, width=width, height=height, text=escape(html))
  