Is it possible to ignore certain part of the slideshow?

[cavo789]

Hi all

I'm using dectkape for converting reveaj.js slideshows to PDF and that's really great. It's amazing. Thank you for that 💯

Some of my slides contains animated gifs and my question is the following: did you know if we can tell Decktape (or Puppeteer) to skip portions like part of a slide (keep title, text and not the image) or skip an entire slide (where the background is an animation f.i;)?

Many thanks!

[astefanutti]

Thanks a lot for the kind feedback!

The --slides option can be used to specify the slides to be exported. If I understand your use case correctly, it may be a bit tedious to exclude a single slide, as you would have to use --slides 1-N-1,N+1-L to exclude slide N. We could imagine to support something like --slides !N.

[cavo789]

Merci Antonin ta prompte réponse.

Excluding a slide based on his number is quite touchy, what if I change my slideshow... I'll probably forget to change the "ignored slide number" and thus, no, not so great for my use case.

And, more, some slides contains a title + one or two lines of text + an animated gif (it's a DOS console f.i.).

When exporting to pdf, it would be great to just ignore the image because right now, the PDF of that slide show a dark screen (the DOS prompt) and not the final result (last frame of the gif f.i.).

Animations are a visual support when I'll give the demo, during a conference and only when running the slideshow is his html version.

My first thought was to use html comments like this:

<!-- screen_only - start -->
![Here is a great animation](./images/demo.gif)
<!-- screen_only - end -->

And, thus, ignore everything between the start and end tag during the exportation.

If I good understand, such features doens't exists yet.

Perhaps one day ;)

Many thanks for giving to us, the Open Source community, such amazing software.

Have a nice day.

[astefanutti]

Your are making very good points. Your understanding is correct, there is currently no such feature. I agree it'd be very useful. I need to think about it more. Let's keep that issue open to hear from other users as well.

[cavo789]

Good morning

Because I really need that feature, I've quickly write a Powershell function to do this. Why Powershell? Because I write in markdown, in multiple files and I've already a big set of ps1 scripts that I run each time for merging all my files into a single one, make some processing like replacing custom functions, variables, ... and inject result in the markdown content.

I'll then reuse my function more than once; also when outputting my markdown file to DOCX, ODT, PDF (not slides but a real document), ...

Here is the Powershell script; perhaps someone will find it usefull and/or give a direction for the js code.

# Mode (reveal or pdf)
$global:mode = ""

# Name of the input file, the one that contains the slides
$global:inputFileName = ""
function getContent() {

    $slides = Get-Content -Path $global:inputFileName -Raw -Encoding UTF8

    $pattern = [regex]$(
        "\n\<\!\-\- conditional [\""'](.*)[\""'] \-\- start \-\-\>" +
        "([\s\S]*?)" +
        "\<\!\-\- conditional [\""'].*[\""'] \-\- end \-\-\>\n"
    )

    do {

        $matches = $pattern.Matches($slides)

        if ($matches.Count -gt 0) {

            $match = $pattern.Match($slides)

            while ($match.Success) {

                # Get the condition which is "pdf" in the example below
                #    <!-- conditional "pdf"-- start -->
                $conditionalMode = $match.captures.groups[1].value

                $command = [Regex]::Escape($match.Value)

                # And now, based on the mode (reveal, pdf) parameter
                # specified as argument to this Powershell script, keep
                # or remove the block
                if ($conditionalMode -eq $global:mode) {
                    # Get the content in the conditional statement
                    $contentBlock = $match.captures.groups[2].value

                    # And keep it
                    $slides = ($slides -replace "$command", $contentBlock)
                }
                else {
                    # Remove the condition and the block since the mode
                    # isn't the specified one
                    $slides = ($slides -replace "$command", "")
                }

                # And get the next one
                $match = $match.NextMatch()
            }

        }
    } Until ($matches.Count -eq 0)

    return $slides
}

$global:mode = "pdf"
$global:inputFileName = "slides.md"

$slides = getContent
Set-Content "c:\tmp\slides_out.md" -Encoding UTF8 -Value $slides

Here the sample on regex101 : https://regex101.com/r/kjOqB9/1

And below the sample. So, when I'll use the Powerschell script given above by setting $global:mode to reveal, only the conditional text for "reveal" and thus "I'm really happy to ..." will be keept, the other ones will be removed.

That way I can run the Powershell function to get a new .md file for my desired output. That new .md will be used with reveal.js and thus decktape will convert the desired one too.

# My demo info session

<!-- conditional "reveal" -- start -->
I'm really happy to be here with you today to talk to you. 
<!-- conditional "reveal" -- end -->

<!-- conditional "pdf" -- start -->
Below are the slides of the presentation given in Brussels 
<!-- conditional "pdf" -- end -->

<!-- conditional "docx" -- start -->
This part will be printed only when exporting to DOCX format...
<!-- conditional "docx" -- end -->

Hope this can help someone.

Have a nice day.