Add PDF pane (#2444)

* Add PDF pane

* Add tests

* Fix matplotlib pane

examples/reference/panes/PDF.ipynb

@@ -0,0 +1,74 @@
+{
+ "cells": [
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "import panel as pn\n",
+    "\n",
+    "pn.extension()"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "The ``PDF`` pane embeds an ``.pdf`` document in a panel if provided a local path, or will link to a remote file if provided a URL.\n",
+    "\n",
+    "#### Parameters:\n",
+    "\n",
+    "For layout and styling related parameters see the [customization user guide](../../user_guide/Customization.ipynb).\n",
+    "\n",
+    "* **``embed``** (boolean, default=False): If given a URL to a file this determines whether the image will be embedded as base64 or merely linked to.\n",
+    "* **``object``** (str or object): The PDF file to display. Can be a string pointing to a local or remote file, or an object with a ``_repr_pdf_`` method.\n",
+    "* **``style``** (dict): Dictionary specifying CSS styles\n",
+    "\n",
+    "___"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "The ``PDF`` pane can be pointed at any local or remote ``.pdf`` file. If given a URL starting with ``http`` or ``https``, the ``embed`` parameter determines whether the image will be embedded or linked to:"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "pdf_pane = pn.pane.PDF('https://www.w3.org/WAI/ER/tests/xhtml/testfiles/resources/pdf/dummy.pdf', width=700, height=1000)\n",
+    "\n",
+    "pdf_pane"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Like any other pane, the ``PDF`` pane can be updated by setting the ``object`` parameter:"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "pdf_pane.object = 'http://www.africau.edu/images/default/sample.pdf'"
+   ]
+  }
+ ],
+ "metadata": {
+  "language_info": {
+   "name": "python",
+   "pygments_lexer": "ipython3"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 4
+}

panel/pane/__init__.py

@@ -13,7 +13,7 @@
 from .holoviews import HoloViews, Interactive # noqa
 from .idom import IDOM # noqa0
 from .ipywidget import IPyWidget # noqa
-from .image import GIF, JPG, PNG, SVG # noqa
+from .image import GIF, JPG, PDF, PNG, SVG # noqa
 from .markup import DataFrame, HTML, JSON, Markdown, Str # noqa
 from .media import Audio, Video # noqa
 from .perspective import Perspective # noqa

panel/pane/image.py

@@ -13,64 +13,40 @@
 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.""")
+class FileBase(DivPaneBase):
 
     embed = param.Boolean(default=True, doc="""
-        Whether to embed the image as base64.""")
-
-    imgtype = 'None'
+        Whether to embed the file as base64.""")
 
-    _rerender_params = ['alt_text', 'link_url', 'embed', 'object', 'style', 'width', 'height']
-
-    _target_transforms = {'object': """'<img src="' + value + '"></img>'"""}
+    _rerender_params = ['embed', 'object', 'style', 'width', 'height']
 
     __abstract = True
 
+    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)
+
     @classmethod
     def applies(cls, obj):
-        imgtype = cls.imgtype
-        if hasattr(obj, '_repr_{}_'.format(imgtype)):
+        filetype = cls.filetype
+        if hasattr(obj, '_repr_{}_'.format(filetype)):
             return True
         if isinstance(obj, string_types):
-            if isfile(obj) and obj.endswith('.'+imgtype):
+            if isfile(obj) and obj.endswith('.'+filetype):
                 return True
-            if isurl(obj, [cls.imgtype]):
+            if isurl(obj, [cls.filetype]):
                 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 + '_')()
+    def _data(self):
+        if hasattr(self.object, '_repr_{}_'.format(self.filetype)):
+            return getattr(self.object, '_repr_' + self.filetype + '_')()
         if isinstance(self.object, string_types):
             if isfile(self.object):
                 with open(self.object, 'rb') as f:
@@ -84,12 +60,43 @@ def _img(self):
             r = requests.request(url=self.object, method='GET')
             return r.content
 
+
+class ImageBase(FileBase):
+    """
+    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 filetype 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.""")
+
+    filetype = 'None'
+
+    _rerender_params = ['alt_text', 'link_url', 'embed', 'object', 'style', 'width', 'height']
+
+    _target_transforms = {'object': """'<img src="' + value + '"></img>'"""}
+
+    __abstract = True
+
     def _b64(self):
-        data = self._img()
+        data = self._data()
         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}"
+        return "data:image/"+self.filetype+f";base64,{b64}"
 
     def _imgshape(self, data):
         """Calculate and return image width,height"""
@@ -99,7 +106,7 @@ def _get_properties(self):
         p = super()._get_properties()
         if self.object is None:
             return dict(p, text='<img></img>')
-        data = self._img()
+        data = self._data()
         if not isinstance(data, bytes):
             data = base64.b64decode(data)
         width, height = self._imgshape(data)
@@ -116,7 +123,7 @@ def _get_properties(self):
             src = self.object
         else:
             b64 = base64.b64encode(data).decode("utf-8")
-            src = "data:image/"+self.imgtype+";base64,{b64}".format(b64=b64)
+            src = "data:image/"+self.filetype+";base64,{b64}".format(b64=b64)
 
         smode = self.sizing_mode
         if smode in ['fixed', None]:
@@ -144,7 +151,7 @@ def _get_properties(self):
 
 class PNG(ImageBase):
 
-    imgtype = 'png'
+    filetype = 'png'
 
     @classmethod
     def _imgshape(cls, data):
@@ -155,7 +162,7 @@ def _imgshape(cls, data):
 
 class GIF(ImageBase):
 
-    imgtype = 'gif'
+    filetype = 'gif'
 
     @classmethod
     def _imgshape(cls, data):
@@ -166,7 +173,7 @@ def _imgshape(cls, data):
 
 class JPG(ImageBase):
 
-    imgtype = 'jpg'
+    filetype = 'jpg'
 
     @classmethod
     def _imgshape(cls, data):
@@ -193,7 +200,7 @@ class SVG(ImageBase):
         Whether to enable base64 encoding of the SVG, base64 encoded
         SVGs do not support links.""")
 
-    imgtype = 'svg'
+    filetype = 'svg'
 
     _rerender_params = ImageBase._rerender_params + ['encode']
 
@@ -208,14 +215,14 @@ def _type_error(self, object):
                              "URL or a SVG XML contents." % type(self).__name__)
         super()._type_error(object)
 
-    def _img(self):
+    def _data(self):
         if (isinstance(self.object, string_types) and
             self.object.lstrip().startswith('<svg')):
             return self.object
-        return super()._img()
+        return super()._data()
 
     def _b64(self):
-        data = self._img()
+        data = self._data()
         if not isinstance(data, bytes):
             data = data.encode('utf-8')
         b64 = base64.b64encode(data).decode("utf-8")
@@ -228,7 +235,7 @@ def _get_properties(self):
         p = super(ImageBase, self)._get_properties()
         if self.object is None:
             return dict(p, text='<img></img>')
-        data = self._img()
+        data = self._data()
         width, height = self._imgshape(data)
         if not isinstance(data, bytes):
             data = data.encode('utf-8')
@@ -242,3 +249,24 @@ def _get_properties(self):
         else:
             html = data.decode("utf-8")
         return dict(p, width=width, height=height, text=escape(html))
+
+
+class PDF(FileBase):
+
+    filetype = 'pdf'
+
+    def _get_properties(self):
+        p = super()._get_properties()
+        if self.object is None:
+            return dict(p, text='<embed></embed>')
+        if self.embed:
+            data = self._data()
+            if not isinstance(data, bytes):
+                data = data.encode('utf-8')
+            base64_pdf = base64.b64encode(data).decode("utf-8")
+            src = f"data:application/pdf;base64,{base64_pdf}"
+        else:
+            src = self.object
+        w, h = self.width or '100%', self.height or '100%'
+        html = f'<embed src="{src}" width={w!r} height={h!r} type="application/pdf">'
+        return dict(p, text=escape(html))

panel/pane/plot.py

@@ -218,7 +218,7 @@ def _imgshape(self, data):
         w, h = self.object.get_size_inches()
         return int(w*72), int(h*72)
 
-    def _img(self):
+    def _data(self):
         self.object.set_dpi(self.dpi)
         b = BytesIO()
 

panel/tests/pane/test_image.py

@@ -4,7 +4,7 @@
 
 from base64 import b64decode, b64encode
 
-from panel.pane import GIF, JPG, PNG, SVG
+from panel.pane import GIF, JPG, PDF, PNG, SVG
 from panel.pane.markup import escape
 from io import BytesIO, StringIO
 
@@ -70,7 +70,7 @@ def test_load_from_byteio():
         memory.write(image_file.read())
 
     image_pane = PNG(memory)
-    image_data = image_pane._img()
+    image_data = image_pane._data()
     assert b'PNG' in image_data
 
 @pytest.mark.skipif(sys.version_info.major <= 2, reason="Doesn't work with python 2")
@@ -83,7 +83,7 @@ def test_load_from_stringio():
         memory.write(str(image_file.read()))
 
     image_pane = PNG(memory)
-    image_data = image_pane._img()
+    image_data = image_pane._data()
     assert 'PNG' in image_data
 
 def test_loading_a_image_from_url():
@@ -92,7 +92,7 @@ def test_loading_a_image_from_url():
           '1700_CE_world_map.PNG'
 
     image_pane = PNG(url)
-    image_data = image_pane._img()
+    image_data = image_pane._data()
     assert b'PNG' in image_data
 
 
@@ -116,3 +116,18 @@ def test_image_link_url(document, comm):
     model = image_pane.get_root(document, comm)
 
     assert model.text.startswith('&lt;a href=&quot;http://anaconda.org&quot;')
+
+
+def test_pdf_embed(document, comm):
+    pdf_pane = PDF('https://www.w3.org/WAI/ER/tests/xhtml/testfiles/resources/pdf/dummy.pdf')
+    model = pdf_pane.get_root(document, comm)
+
+    assert model.text.startswith("&lt;embed src=&quot;data:application/pdf;base64,")
+
+
+def test_pdf_no_embed(document, comm):
+    url = 'https://www.w3.org/WAI/ER/tests/xhtml/testfiles/resources/pdf/dummy.pdf'
+    pdf_pane = PDF(url, embed=False)
+    model = pdf_pane.get_root(document, comm)
+
+    assert model.text.startswith(f"&lt;embed src=&quot;{url}")