[BUG] Convert to HTML works for one scene, but does not work for multiple scenes

[mcnica89]

Terms

• Checked the existing issues and discussions to see if my issue had not already been reported;
• Checked the [frequently asked questions]](https://manim-slides.eertmans.be/latest/faq.html);
• Read the installation instructions;
• Created a virtual environment in which I can reproduce my bug;

Describe the issue

When I use the convert to html feature with multiple scenes, the folder with all the .mp4 media is created correctly,. but the html file that plays from it is not working for some reason. It is simply black and I cannot advance slides (I can use "F" to make it fullscreen). When I do one scene at a time, it DOES work correctly. This issue was also reported on reddit https://www.reddit.com/r/manim/comments/1fzcv7z/manimslides_convert_gives_html_that_is_a_blank/ (which is what made me try rendering just one scene at a time)

Command

manim-slides convert Scene1 Scene2 output.html

Issue Type

Bug when presenting with HTML/PowerPoint/... format (manim-slides convert)

Python version

Python 3.9.12

Python environment

Manim Slides version: 5.1.10
Python executable: /Users/mnica/opt/anaconda3/bin/python3
Manim bindings:
/Users/mnica/opt/anaconda3/lib/python3.9/site-packages/scipy/__init__.py:146: UserWarning: A NumPy version >=1.16.5 and <1.23.0 is required for this version of SciPy (detected version 1.26.4
  warnings.warn(f"A NumPy version >={np_minversion} and <{np_maxversion}"
	manim (version: 0.18.1)
	manimgl not found
Qt API: pyqt5 (version: 5.9.7)
(base) mnica@Mihais-MBP Downloads % manim-slides checkhealth
Manim Slides version: 5.1.10
Python executable: /Users/mnica/opt/anaconda3/bin/python3
Manim bindings:
/Users/mnica/opt/anaconda3/lib/python3.9/site-packages/scipy/__init__.py:146: UserWarning: A NumPy version >=1.16.5 and <1.23.0 is required for this version of SciPy (detected version 1.26.4
  warnings.warn(f"A NumPy version >={np_minversion} and <{np_maxversion}"
	manim (version: 0.18.1)
	manimgl not found
Qt API: pyqt5 (version: 5.9.7)

What is your platform?

macOS

Other platform

No response

Manim Slides Python code

No response

Relevant log output

No response

Screenshots

No response

Additional information

No response

Recommended fix or suggestions

No response

[jeertmans]

Hi @mcnica89, thanks for reporting this bug!

I feel this is a duplicate of #496, did you check it?

If that is the case, a fix has already been merged, but was not yet released to PyPI. I just released manim-slides==5.2.0, which should contain the fix.

Let me know :-)

[svandenhaute]

I am encountering the same issue on the new 5.3.0. Multiple scenes are rendered and presented correctly using manim-slides present, but when converting to HTML it simply shows a black screen after the first scene.

[MANISHJOSHI23]

I am also facing the same issue on manim-slides 5.3.0. When I use default configuration without using --use-template the prefix is added to the html file. But when I copied the same configuration file and used use-template command the prefix is not added to the html file

[jeertmans]

@svandenhaute, could you provide a minimal working example (MWE)? I cannot reproduce your bug locally. Same for @MANISHJOSHI23.

What I did:

manim-slides render example.py BasicExample ThreeDExample
manim-slides convert BasicExample ThreeDExample test.html --open
manim-slides convert BasicExample ThreeDExample test.html --open --use-template manim_slides/templates/revealjs.html

and all commands work as expected (both in full-screen and not).

FYI @MANISHJOSHI23, you might want to update your template file if it is too old.

[MANISHJOSHI23]

yes, I think the template file I was using was old, now it's working. Thank you for your response and the great work you are doing