I have an ipython notebook with an embedded image from my local drive. I was expecting it to be embedded in the JSON along with the output of code cells, but when I distributed the notebook, the image did not appear to users. What is the recommended way (or ways) to embed an image in a Notebook, so that it doesn't disappear if users rerun code cells, clear cell output, etc.?
The notebook system caches images included with , but they last only until the python "kernel" serving the notebook is restarted. If I rename the image file on disk, I can close and reopen the notebook and it still shows the image; but it disappears when I restart the kernel.
Edit: If I generate an image as code cell output and then export the notebook to html, the image is embedded in the html as encoded data. Surely there must be a way to hook into this functionality and load the output into a markdown (or better yet "raw nbconvert") cell?
from IPython.display import Image
Image(filename='imagename.png')
will be exported (with ipython nbconvert) to html that contains the following:
<div class="output_png output_subarea output_execute_result">
<img src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAnAAAAFgCAYAAAA...
</div>
However, even when I manually embedded this snippet into a markdown cell, I couldn't get the image to display. What am I doing wrong?
Update (2020)
Apparently, the problem has (finally!) been addressed in the newer notebook / Jupyter versions: as of 2018 (thanks for the link #Wayne), the html sanitizer will accept an embedded html image, as in <img src="data:image/png;base64,iV...> . Markdown image syntax also accepts images as embedded data, so there are two ways to do this. Details in these helpful answers:
markdown image syntax (answer by #id01)
html element syntax (in answer by #tel -- note that it works now!)
Are you happy to use an extra code cell to display the image? If so, use this:
from IPython.display import Image
Image(filename="example.png")
The output cell will have the raw image data embedded in the .ipynb file so you can share it and the image will be retained.
Note that the Image class also has a url keyword, but this will only link to the image unless you also specify embed=True (see the documentation for details). So it's safer to use the filename keyword unless you are referring to an image on a remote server.
I'm not sure if there is an easy solution if you require the image to be included in a Markdown cell, i.e. without a separate code cell to generate the embedded image data. You may be able to use the python markdown extension which allows dynamically displaying the contents of Python variables in markdown cells. However, the extension generates the markdown cells dynamically, so in order to retain the output when sharing the notebook you will need to run ipython nbconvert --to notebook original_notebook.ipynb --output preprocessed_notebook using the preprocessor pymdpreprocessor.py as mentioned in the section "Installation". The generated notebook then has the data embedded in the markdown cell as an HTML tag of the form <img src="data:image/png;base64,..."> so you can delete the corresponding code cell from preprocessed_notebook.ipynb. Unfortunately, when I tried this the contents of the <img> tag weren't actually displayed in the browser, so not sure if this is a viable solution. :-/
A different option would be to use the Image class in a code cell to generate the image as above, and then use nbconvert with a custom template to remove code input cells from the notebook. See this thread for details. However, this will strip all code cells from the converted notebook, so it may not be what you want.
The reason why the
<img src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAnAAAAFgCAYAAAA...
tag doesn't do anything when you put it in a markdown cell is because IPython uses an HTML sanitizer (something called Google Caja) that screens out this type of tag (and many others) before it can be rendered.
The HTML sanitizer in IPython can be completely disabled by adding the following line to your custom.js file (usually located at ~/.ipython/profile_default/static/custom/custom.js):
iPython.security.sanitize_html = function (html) { return html; };
It's not a great solution though, as it does create a security risk, and it doesn't really help that much with distribution.
Postscript:
The ability to render base64 encoded strings as images != obvious security concern, so there should be a way for the Caja people to eventually allow this sort of thing through (although the related feature request ticket was first opened back in 2012, so don't hold your breath).
I figured out that replacing the image URL in the  with a base64 URL, similar to the ones found above, can embed an image in a markdown container.
Example markdown:
If using the IPython HTML() function to output raw HTML, you can embed a linked image in base64 inside an <img> tag using the following method:
import base64
import requests
from IPython.core.display import HTML
def embedded_image(url):
response = requests.get(url)
uri = ("data:" +
response.headers['Content-Type'] + ";" +
"base64," + str(base64.b64encode(response.content).decode('utf-8')))
return uri
# Here is a small example. When you export the notebook as HTML,
# the image will be embedded in the HTML file
html = f'<img src="{embedded_image("https://upload.wikimedia.org/wikipedia/commons/5/56/Kosaciec_szczecinkowaty_Iris_setosa.jpg")}" />'
HTML(html)
UPDATE: As pointed out by #alexis, this doesn't actually answer the question correctly, this will not allow users to re-run cells and have images persist (this solution only allows one to embed the images into exports).
As of Jupyter Notebook 5, you can attach image data to cells, and refer to them from the cell via attachment:<image-file-name>. See the menu Edit > Insert Image, or use drag and drop.
Unfortunately, when converting notebooks with attached (embedded) images to HTML, those images will not show up.
To get them into the HTML code, you can use (for instance) nbtoolbelt.
It will replace those attachment: references by data: with the image data embedded in the img tag.
Related
can someone help me to resize an HTML file produce with plotly in Jupyter?
This is the code I am using to save to an HTML file:
fig.write_html("D:\jupyter\image.html")
It works but now I want to control for the size. Here (https://plotly.com/python/interactive-html-export/) is suggested how to do it but I cannot get my head around to how specifically write the code to not get a big image
If you type fig.write_html? inside a cell you can read all the documentation, which is a little more explicit than the document you posted. In short
fig.write_html("output.html",
include_plotlyjs="cdn")
Should produce a file ~3MB smaller than the one you are getting now as this option point to the plotly.js online instead of include it on the output.
I am running Python 3.7 on Windows using pycharm. I have a jupyter notebook and I would like to embed an image into the notebook. I know all the ways of doing standard embedding with markdown language, BUT ideally what I want is:
a. Embed the image via markdown language, i.e. the notebook cell is in 'markdown' state, not 'Code' state, AND ALSO
b. Have it able to export to HTML and retain that image in the HTML file. i.e. on the notebook. I want to click File -> Download as -> HTML (.html), save the notebook file in .html format, and then when I send it to my buddy, the image that I attached is in the notebook, and he sees it.
I know i could do this in a cell ('code'):
from IPython.display import Image
Image(filename="myfile.jpg")
but I do not want to use 'Code', since when I send to my buddy, he will see the In [] code statement and the Out [] of the image in the notebook html file.
Note: This would be an image that was on my laptop that I would want in the html formatted exported notebook. It is NOT on the web where he could refer to it with a www type statement. Unless I'm crazy, there is no way to do this with markdown command in a cell, the only way to do it (with the image embedded 'permanently' into the .html format of the notebook), would be via a cell that was in 'Code' celltype.
When you use a code cell to show an image and then export the notebook to an HTML file, the image is converted to Base64 and the code directly used in the src attribute of the <img> tag. You can apply the same procedure with images included in markdown cells.
First, encode your image as Base64, e.g. by using one of the online enocders.
Create a markdown cell and include an <img> tag which uses your Base64 code, e.g.:
<img src="data:image/png;base64,CODE_FOLLOWS_HERE" />
Evaluate the cell and you should already see your image.
If you now export your notebook to HTML, the image should be included in the file the same way as images from code cells.
The only disadvantage with this approach is that your markdown cell gets cluttered with the (probably long) Base64 code. However, this is manageable by e.g. using a markdown cell dedicated solely to the image without other content.
You can install the Unofficial Jupyter Notebook Extensions.
It has some interesting extensions (e.g. spell checker, collapsible headings, ...). One of the extensions is Export HTML With Embedded Images which exactly does what you want.
To install Nbextensions using pip do the following:
$ pip install jupyter_contrib_nbextensions
$ pip install jupyter_nbextensions_configurator
$ jupyter contrib nbextension install --user
$ jupyter nbextensions_configurator enable --user
Then you will see in your Jupyter homepage a new tab (Nbextensions), where you can enable and configure different extension.
After enabling the "Export HTML With Embedded Images", you will see the corresponding option in the "File-Download as" menu.
My complete solution is based on Milania and
encoding-an-image-file-with-base64
how-to-base64-encode-an-image-using-python
BytesIO.getvalue
the code
import base64, io, IPython
from PIL import Image as PILImage
image = PILImage.open(image_path)
output = io.BytesIO()
image.save(output, format='PNG')
encoded_string = base64.b64encode(output.getvalue()).decode()
html = '<img src="data:image/png;base64,{}"/>'.format(encoded_string)
IPython.display.HTML(html)
For me, on Visual Studio Code, something like this did the trick (in a markdown cell, as you requested, and a image that you want to embed in your notebook and further be exported to the html output):
<figure>
<img src="./notebook_img/diptera_taxat_yes_no.jpg" width="200"/>
<figcaption>Limit the search on Diptera</figcaption>
</figure>
Where the image is located in "./notebook_img" relative to the location of the notebook (in this sense, the notebook is located in .)
Your buddy will not see the code from above when reading the HTML exported file, so that should satisfy the requested need as far as I understand. He will also not need the folder "notebook_img".
For PDF exports, I'm trying to export the space name to the bottom center of the export.
I tried the following but no luck so far:
#bottom-center
{
content: $space.getName();
}
I think the space variables do not work within the PDF CSS Stylesheet.
Is there another way of possibly achieving this?
I look forward to your ideas.
You might want to have a look at our Scroll PDF Exporter for Confluence.
Scroll PDF Exporter is an app for Confluence Server and Cloud that allows you to further customize your exports using a graphical template designer.
One key feature of the app is the possibility to use placeholders for specific metadata (e.g. the space name). Those placeholders can be used in the header or footer of your exported file and will be replaced during export with the wanted information.
You can find further information about all available placeholders in our Scroll PDF Exporter documentation.
For your specific use case the placeholder "Space Name" should work.
You can try out Scroll PDF Exporter using a 30 day trial license via the Atlassian Marketplace.
In case you have any further questions regarding the app, please get in touch with us via support[at]k15t.com.
We'll be happy to help.
Best,
Nils
I'm trying out Pandoc on OS X, and results thus far are impressive. One blocking problem, however, is getting CSS styles to work on inline code samples. I'm converting from Markdown to PDF.
I have this string in my source:
* Create a simple HTML document (<span class="filename">simple.html</span>) and load it into the browser via the file system
I've also tried this:
* Create a simple HTML document (`simple.html`{.filename}) and load it into the browser via the file system
I'd like to apply the class "filename" to the enclosed text in each case, but it doesn't seem to do anything to the output. However the manual says:
Some output formats can use this information to do syntax highlighting. Currently, the only output formats that uses this information are HTML and LaTeX.
Here's my command:
pandoc \
--output ./output.pdf \
--css source/styles.css \
source/en/docs/input.md
I'm converting to PDF, which is written by LaTeX by Pandoc internally. Can I get this to work? Or, can I use a style defined using a LaTeX command? - it doesn't have to be CSS. However, it must be a style system - it's not workable to change italic/font/colour attributes on each occasion.
I've tried sending output temporarily to HTML, and in that situation the styles are imported directly from the specific style asset. So, my stylesheet specification and span markup is correct, at least for one output format.
Addenda
A couple of afterthoughts:
The solution does not have to be Pandoc or Markdown. However, it does need to be a trivial text-based markup language that can convert reliably to PDF, as I want to store the document files on Git for easy forking and merging. I'm not keen on HTML as it is verbose, and engines to convert it aren't that great (though, admittedly, my formatting requirements are modest).
The HTML output from Pandoc is fine, so if I can find something that converts the (simple) HTML/CSS to PDF reliably, I'll be fine. Of course, Pandoc should be able to do this, but inline styles (for the background colour on code fragments) aren't rendered. This might be a faff, as I'll have to reintroduce things like page-breaks, which can be non-trivial in HTML-to-PDF converters.
"I'd like to apply the class "filename" to the enclosed text in each case, but it doesn't seem to do anything to the output."
It works for HTML. Running Pandoc interactively, ^D to see the resulting code:
$> pandoc -f markdown -t html
* Create a simple HTML document (`simple.html`{.filename}) and load it.
^D
<ul>
<li>Create a simple HTML document (<code class="filename">simple.html</code>) and load it.</li>
</ul>
It doesn't work for LaTeX if you use the .filename class. You need to use one of the known classnames:
$> pandoc -f markdown -t latex
* Create a simple HTML document (`simple.html`{.filename}) and load it.
^D
\begin{itemize}
\tightlist
\item
Create a simple HTML document (\texttt{simple.html}) and load it.
\end{itemize}
Now using one of the known classnames, like .bash, .postscript, .php, ...:
$> pandoc -f markdown -t latex
* Create a simple HTML document (`simple.html`{.bash}) and load it.
^D
\begin{itemize}
\tightlist
\item
Create a simple HTML document (\VERB|\KeywordTok{simple.html}| and
load it.
\end{itemize}
To convert HTML + CSS into PDF, you can also look into PrinceXML, which is free for non-commercial use.
I don't know LaTeX at all, but have hacked this solution using this helpful manual. First, create a style:
\definecolor{silver}{RGB}{230,230,230}
\newcommand{\inlinecodeblock}[1]{
\colorbox{silver}{
\texttt{#1}
}
}
And here's how to use it:
Some \inlinecodeblock{inline code}, and some widgets, go here
This creates a style with a background colour and a monospaced font. The margin and padding are a bit large for my preferences, but it's a very useable start. Here's what it looks like:
The disadvantage is that if I wish to output to a format that supports styles proper (such as HTML) then these are lost. Also, my solution only works with LaTeX/PDF. Thus, if you can fix these issues, please add a better answer!
Addendum: I have a better approach, which is thus:
\newcommand{\inlinecodeblock}[1]{
\fboxsep 1pt
\fboxrule 0pt
\colorbox{silver}{\strut{\texttt{#1}}}
}
This avoids the problem of excess horizontal padding - I think it was the line break in the colorbox parameter that did it. I've added in strut, which keeps highlights the same height regardless of whether the text has descenders.
It's not perfect though - there's still too much horizontal margin outside the box, and a comma after a box will still orphan onto the next line. I may give up with LaTeX, and render to HTML from Pandoc, and then use wkhtmltopdf to render the final document.
I want to export a few Pages to pdf/xls. By Pages I mean as the eye sees it - a screenshot of the Page's contents. I know how to build pdf/xls documents using 3rd party tools but is there any way to quickly export the rendered contents of say a Panel?
edit: maybe a tool that can render the page's output as a browser would, and save it as an image file?
There is an open source console program named wkhtmltopdf which you could call from asp.net to convert the page. It can convert to PDF or an image with wkhtmltoimage (JPG, PNG, etc.) using the webkit rendering engine.
Check my answer to this question to see an example of how to convert from a html to a pdf using C#:
Easiest way of porting html table data to readable document
I can recommend http://www.screengrab.org/ for firefox.