presenterm-export dependencies update

[jacanchaplais]

Hi there! Very cool work with this tool, I think I'll make a lot of use out of it!

I just wanted to say, for the export functionality, the statement in the docs

The only external dependency you'll need is tmux.

Is not quite right. I installed it fresh on my system using micromamba.

My system specs

❯ fastfetch                                                                                   slides   impure 16:04:15
          ▗▄▄▄       ▗▄▄▄▄    ▄▄▄▖             jacan@nixos
          ▜███▙       ▜███▙  ▟███▛             -----------
           ▜███▙       ▜███▙▟███▛              OS: NixOS 24.11.20240811.a58bc8a (Vicuna) x86_64
            ▜███▙       ▜██████▛               Host: 20EQS3MB07 (ThinkPad P50)
     ▟█████████████████▙ ▜████▛     ▟▙         Kernel: Linux 6.6.44
    ▟███████████████████▙ ▜███▙    ▟██▙        Uptime: 7 hours, 23 mins
           ▄▄▄▄▖           ▜███▙  ▟███▛        Packages: 5661 (nix-system), 5104 (nix-user)
          ▟███▛             ▜██▛ ▟███▛         Shell: zsh 5.9
         ▟███▛               ▜▛ ▟███▛          Display (AUO61ED): 1920x1080 @ 60 Hz in 16″ [Built-in]
▟███████████▛                  ▟██████████▙    DE: none+bspwm
▜██████████▛                  ▟███████████▛    WM: bspwm (X11)
      ▟███▛ ▟▙               ▟███▛             Theme: Breeze [GTK2], Adwaita-dark [GTK3/4]
     ▟███▛ ▟██▙             ▟███▛              Terminal: bwrap
    ▟███▛  ▜███▙           ▝▀▀▀▀               CPU: Intel(R) Core(TM) i7-6820HQ (8) @ 3.60 GHz
    ▜██▛    ▜███▙ ▜██████████████████▛         GPU 1: Intel HD Graphics 530 @ 1.05 GHz [Integrated]
     ▜▛     ▟████▙ ▜████████████████▛          GPU 2: NVIDIA Quadro M1000M [Discrete]
           ▟██████▙       ▜███▙                Memory: 2.82 GiB / 15.45 GiB (18%)
          ▟███▛▜███▙       ▜███▙               Swap: Disabled
         ▟███▛  ▜███▙       ▜███▙              Disk (/): 0 B / 7.73 GiB (0%) - tmpfs
         ▝▀▀▀    ▀▀▀▀▘       ▀▀▀▘              Disk (/mnt/crucial2TB): 814.65 GiB / 1.82 TiB (44%) - btrfs
                                               Disk (/nix): 183.97 GiB / 237.97 GiB (77%) - btrfs [Read-only]
                                               Local IP (wlp4s0): 192.168.0.39/24
                                               Battery: 45% [Discharging]
                                               Locale: en_GB.UTF-8

                                                                       
                                                                       

I found that I needed to additionally install pygobject and pango from conda-forge to get the install working, otherwise the program would try to load libraries which weren't there.

Error logs

Before installing pygobject:

❯ presenterm-export --version                                                                 slides   impure 15:51:47

-----

WeasyPrint could not import some external libraries. Please carefully follow the installation steps before reporting an issue:
https://doc.courtbouillon.org/weasyprint/stable/first_steps.html#installation
https://doc.courtbouillon.org/weasyprint/stable/first_steps.html#troubleshooting 

-----

Traceback (most recent call last):
  File "/home/jacan/Documents/code/python/.micromamba/envs/slides/bin/presenterm-export", line 5, in <module>
    from presenterm_export.cli import main
  File "/home/jacan/Documents/code/python/.micromamba/envs/slides/lib/python3.12/site-packages/presenterm_export/cli.py", line 14, in <module>
    from presenterm_export.pdf import PdfOptions, generate_pdf
  File "/home/jacan/Documents/code/python/.micromamba/envs/slides/lib/python3.12/site-packages/presenterm_export/pdf.py", line 3, in <module>
    import weasyprint
  File "/home/jacan/Documents/code/python/.micromamba/envs/slides/lib/python3.12/site-packages/weasyprint/__init__.py", line 419, in <module>
    from .css import preprocess_stylesheet  # noqa: I001, E402
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/jacan/Documents/code/python/.micromamba/envs/slides/lib/python3.12/site-packages/weasyprint/css/__init__.py", line 28, in <module>
    from .computed_values import COMPUTER_FUNCTIONS
  File "/home/jacan/Documents/code/python/.micromamba/envs/slides/lib/python3.12/site-packages/weasyprint/css/computed_values.py", line 9, in <module>
    from ..text.ffi import ffi, pango, units_to_double
  File "/home/jacan/Documents/code/python/.micromamba/envs/slides/lib/python3.12/site-packages/weasyprint/text/ffi.py", line 431, in <module>
    gobject = _dlopen(
              ^^^^^^^^
  File "/home/jacan/Documents/code/python/.micromamba/envs/slides/lib/python3.12/site-packages/weasyprint/text/ffi.py", line 420, in _dlopen
    return ffi.dlopen(names[0])  # pragma: no cover
           ^^^^^^^^^^^^^^^^^^^^
  File "/home/jacan/Documents/code/python/.micromamba/envs/slides/lib/python3.12/site-packages/cffi/api.py", line 150, in dlopen
    lib, function_cache = _make_ffi_library(self, name, flags)
                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/jacan/Documents/code/python/.micromamba/envs/slides/lib/python3.12/site-packages/cffi/api.py", line 832, in _make_ffi_library
    backendlib = _load_backend_lib(backend, libname, flags)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/jacan/Documents/code/python/.micromamba/envs/slides/lib/python3.12/site-packages/cffi/api.py", line 827, in _load_backend_lib
    raise OSError(msg)
OSError: cannot load library 'gobject-2.0-0': gobject-2.0-0: cannot open shared object file: No such file or directory.  Additionally, ctypes.util.find_library() did not manage to locate a library called 'gobject-2.0-0'

Before installing pango:

❯ presenterm-export --version                                                                  14s   slides   impure 15:55:19

-----

WeasyPrint could not import some external libraries. Please carefully follow the installation steps before reporting an issue:
https://doc.courtbouillon.org/weasyprint/stable/first_steps.html#installation
https://doc.courtbouillon.org/weasyprint/stable/first_steps.html#troubleshooting 

-----

Traceback (most recent call last):
  File "/home/jacan/Documents/code/python/.micromamba/envs/slides/bin/presenterm-export", line 5, in <module>
    from presenterm_export.cli import main
  File "/home/jacan/Documents/code/python/.micromamba/envs/slides/lib/python3.12/site-packages/presenterm_export/cli.py", line 14, in <module>
    from presenterm_export.pdf import PdfOptions, generate_pdf
  File "/home/jacan/Documents/code/python/.micromamba/envs/slides/lib/python3.12/site-packages/presenterm_export/pdf.py", line 3, in <module>
    import weasyprint
  File "/home/jacan/Documents/code/python/.micromamba/envs/slides/lib/python3.12/site-packages/weasyprint/__init__.py", line 419, in <module>
    from .css import preprocess_stylesheet  # noqa: I001, E402
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/jacan/Documents/code/python/.micromamba/envs/slides/lib/python3.12/site-packages/weasyprint/css/__init__.py", line 28, in <module>
    from .computed_values import COMPUTER_FUNCTIONS
  File "/home/jacan/Documents/code/python/.micromamba/envs/slides/lib/python3.12/site-packages/weasyprint/css/computed_values.py", line 9, in <module>
    from ..text.ffi import ffi, pango, units_to_double
  File "/home/jacan/Documents/code/python/.micromamba/envs/slides/lib/python3.12/site-packages/weasyprint/text/ffi.py", line 434, in <module>
    pango = _dlopen(
            ^^^^^^^^
  File "/home/jacan/Documents/code/python/.micromamba/envs/slides/lib/python3.12/site-packages/weasyprint/text/ffi.py", line 420, in _dlopen
    return ffi.dlopen(names[0])  # pragma: no cover
           ^^^^^^^^^^^^^^^^^^^^
  File "/home/jacan/Documents/code/python/.micromamba/envs/slides/lib/python3.12/site-packages/cffi/api.py", line 150, in dlopen
    lib, function_cache = _make_ffi_library(self, name, flags)
                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/jacan/Documents/code/python/.micromamba/envs/slides/lib/python3.12/site-packages/cffi/api.py", line 832, in _make_ffi_library
    backendlib = _load_backend_lib(backend, libname, flags)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/jacan/Documents/code/python/.micromamba/envs/slides/lib/python3.12/site-packages/cffi/api.py", line 827, in _load_backend_lib
    raise OSError(msg)
OSError: cannot load library 'pango-1.0-0': pango-1.0-0: cannot open shared object file: No such file or directory.  Additionally, ctypes.util.find_library() did not manage to locate a library called 'pango-1.0-0'

It now works, and I have a minimal environment.yml file with contents:

name: slides
channels:
  - conda-forge
dependencies:
  - python=3.12.5
  - pygobject=3.48.2
  - pango=1.54.0
  - pip:
    - presenterm-export==0.2.4

But you may want to consider updating your documentation, or the automatically installed dependencies.

Thanks for your great work on this project!

[mfontanini]

Sorry I never replied here! I think this is not presenterm-export's fault but instead weasyprint's. They should be specifying those dependencies, not every consumer of their library. Weirdly, I can install presenterm-export in a clean virtual env and I see none of those 2 dependencies installed and the tool works fine for me 🤷.