Not So Quick Start Guide - vinnymeller/molten-nvim GitHub Wiki

Not So Quick Start Guide

This will walk you through the install, light configuration, and basic usage! It's a little less than quick in the interest of explaining what's necessary and what's not.

Installation

Dependencies

This plugin has many dependencies if you would like the full experience. Most of these dependencies are optional and are only necessary if you would like image support.

Image.nvim

Image.nvim is a neovim plugin that provides an api for rendering images. Rending images in the terminal is not the most straight forward thing in the world. As such, I'd recommend clicking that link, configuring image.nvim, making sure it works with their builtin markdown integration, and then coming back here to finish setting up Molten.

After Image.nvim is working

There are a few image.nvim config options that will dramatically improve your experience. Here is a sample configuration that leaves out the document integrations (note if you want to disable these, please see the image.nvim readme.

-- image nvim options table. Pass to `require('image').setup`
{
  backend = "kitty", -- Kitty will provide the best experience, but you need a compatible terminal
  integrations = {}, -- do whatever you want with image.nvim's integrations
  max_width = 100, -- tweak to preference
  max_height = 12, -- ^
  max_height_window_percentage = math.huge, -- this is necessary for a good experience
  max_width_window_percentage = math.huge,
  window_overlap_clear_enabled = true,
  window_overlap_clear_ft_ignore = { "cmp_menu", "cmp_docs", "" },
},

Important: max_width and max_height must be set, or large images can cause your terminal to crash. I recommend the values 100 and 12, that feels natural to me, but feel free to increase or decrease as you see fit (font size will make a large difference here).

Less important but still important: Setting max_height_window_percentage to math.huge is necessary for Molten to render output windows at the correct dimensions. This value defaults to 50 or 60%, and for a plugin like Molten, which tries to display a window that's only as tall as it needs to be, window percentage caps are problematic. Note that even setting this value to 100% is not enough, as this can cause images to be resized instead of cropped when the molten output window is partially off-screen, and the image is (until you scroll) taller than the window.

Pinning Image.nvim version

Image.nvim is still in it's early stages, and as such, breaks more often than other plugins. For the most reliable experience with Molten, you should pin the version of image.nvim that you use.

Different package managers allow for pinning versions differently, so please refer to your package manager's documentation if you don't use Lazy.

[!NOTE] Note that I will always use the latest version of image.nvim, and will try to keep this wiki up to date with the last working version. But if you're having issues with the version listed here, please first try the latest image.nvim version, and then open an issue or wiki pr.

version = "1.1.0",

Python Deps

Note: It's recommended that you install python packages in a virtual environment as outlined in the venv guide

Absolutely necessary python packages:

pynvim (for the Remote Plugin API)
jupyter_client (for interacting with Jupyter)

Packages only required for their specific image support:

cairosvg (for displaying transparent SVG images)
- If you don't have cariosvg installed, we fallback to image.nvim's svg support, which uses the ImageMagic library. From what I've gathered, this library has differing levels of support for SVGs with transparent backgrounds. So I'd recommend trying to get away without cairo, and only installing it if you notice an issue.
pnglatex (for displaying TeX formulas)
- Note that this has additional, non-pip, dependencies. You need a TeX distribution installed on your machine as well as the following executables: pdftopnm, pnmtopng, pdfcrop which you can find through your system package manager.
plotly and kaleido (for displaying Plotly figures)
- In order to render plotly figures I've also needed nbformat installed in the project venv, unfortunately installing it in the neovim venv did not work (see venv guide)
pyperclip if you want to use molten_copy_output

.NET Deps

dotnet tool install -g Microsoft.dotnet-interactive
dotnet interactive jupyter install

[!NOTE] I personally do not use .NET (nor have I ever), all the tooling for .NET is working in theory, but hasn't been tested by myself. This is something Magma supported, and there's no reason that it shouldn't still work, but I'll be able to provide limited help here.

Sample Lazy.nvim Config

return {
    {
        "benlubas/molten-nvim",
        dependencies = { "3rd/image.nvim" },
        build = ":UpdateRemotePlugins",
        init = function()
            -- these are examples, not defaults. Please see the readme
            vim.g.molten_image_provider = "image.nvim"
            vim.g.molten_output_win_max_height = 20
            vim.g.molten_auto_open_output = false
        end,
    },
    {
        -- see the image.nvim readme for more information about configuring this plugin
        "3rd/image.nvim",
        opts = {
            backend = "kitty", -- whatever backend you would like to use
            max_width = 100,
            max_height = 12,
            max_height_window_percentage = math.huge,
            max_width_window_percentage = math.huge,
            window_overlap_clear_enabled = true, -- toggles images when windows are overlapped
            window_overlap_clear_ft_ignore = { "cmp_menu", "cmp_docs", "" },
        },
    }
},

A Note on Remote Plugins

Molten is a remote plugin. This means that the first time you install, and after you update Molten you need to run the :UpdateRemotePlugins command in Neovim. This can be done with some package mangers (like Lazy for example) automatically.

But if things aren't working, make sure that you run that command and then restart your editor.

NixOS Installation

If you're on NixOS it might be a little more difficult to get everything working.

NixOS Home Manager Installation

If you use home manager and have configure Neovim through it, you can set up the dependencies like so:

  # home.nix or wherever you configure neovim
  { pkgs, ... }:
  let 
    # the vimPlugins.molten-nvim package has not been merged into nixpkgs yet but for now you can use this
    molten-nvim = pkgs.callPackage pkgs.vimUtils.buildVimPlugin {
      pname = "molten-nvim";
      version = "2023-10-21";
      src = fetchFromGitHub {
        owner = "benlubas";
        repo = "molten-nvim";
        rev = "f9c28efc13f7a262e27669b984f3839ff5c50c32";
        sha256 = "1r8xf3jphgml0pax34p50d67rglnq5mazdlmma1jnfkm67acxaac";
      };
      meta.homepage = "https://github.com/benlubas/molten-nvim/";
    };
  in {
    # ... other config
    programs.neovim = {
      # whatever other neovim configuration you have
      plugins = with pkgs.vimPlugins; [
        # ... other plugins
        image-nvim
        molten-nvim
      ];
      extraPackages = with pkgs; [
        # ... other packages
        imagemagick
      ];
      extraLuaPackages = ps: [
        # ... other lua packages
        magick
      ];
      extraPython3Packages = ps: with ps; [
        # ... other python packages
        pynvim
        jupyter-client
        cairosvg
        pnglatex
        plotly
        pyperclip
      ];
    };
  }

There are multiple ways to manage your Lua configuration so follow the instructions for setting up Image.nvim and molten-nvim for your specific setup.

Customize

The README is the best resource for customization info. Additionally, you'll want to setup some keybinds for common commands like :MoltenEvaluateVisual, more information about doing this is also in the README!