revealjs navigation with vertical slides: fragment / code-line-number stepping is also triggered by horizontal navigation

[skwde]

Bug description

When using vertical slides in revealjs combined with code-line-numbers horizontal navigation requires to step through the entire code-line-numbers before the next horizontal slide is shown.

Steps to reproduce

Use following test.qmd:

---
format:
  revealjs:
    navigation-mode: vertical
    controls: true
    toc: true
    toc-depth: 1
---

# horizontal 1

## vertical 1-1

```{.python code-line-numbers="1|2"}
a
b
```

# horizontal 2

## vertical 2-1

a

::: {.fragment .fade-in}
c
:::

# horizontal 3

Expected behavior

code-line-numbers / fragments are ignored when vertical slides are present and one tries to jump to the next horizontal slide.

Actual behavior

Before the next horizontal slide is shown one has to step through all fragments on the current slide.

Your environment

• VSCode (latest) on MacOS using a devcontainer
• devcontainer running debian bookworm

Quarto check output

# quarto check
Quarto 1.4.553
[✓] Checking versions of quarto binary dependencies...
      Pandoc version 3.1.11: OK
      Dart Sass version 1.69.5: OK
      Deno version 1.37.2: OK
[✓] Checking versions of quarto dependencies......OK
[✓] Checking Quarto installation......OK
      Version: 1.4.553
      Path: /opt/quarto/bin

[✓] Checking tools....................OK
      TinyTeX: v2024.04
      Chromium: (not installed)

[✓] Checking LaTeX....................OK
      Using: TinyTex
      Path: /root/.TinyTeX/bin/x86_64-linux
      Version: 2024

[✓] Checking basic markdown render....OK

[✓] Checking Python 3 installation....OK
      Version: 3.12.3 (Conda)
      Path: /opt/conda/bin/python
      Jupyter: 5.7.2
      Kernels: python3

[✓] Checking Jupyter engine render....OK

[✓] Checking R installation...........(None)

      Unable to locate an installed version of R.
      Install R from https://cloud.r-project.org/

[cscheid]

Expected behavior

code-line-numbers / fragments are ignored when vertical slides are present and one tries to jump to the next horizontal slide.

I'm not sure that would be correct either, because you added the fragments there, presumably for a reason, and ignoring them doesn't seem right.

[skwde]

Hmm ok, that behavior is a bit odd in my opinion as it goes against the idea of horizontal / vertical slides.
To my understanding horizontal slides are for content structuring while vertical slides go into details.
So I don't see why horizontal animation is expected in that case.
In general I am having a hard time to think of a use case for horizontal animation when vertical slides are present.

In any case, maybe an option to specify would be a good compromise, something like fragment-reveal with values both, vertical or horizontal would be a good choice. In that way nobodies use case breaks.