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* Treemacs - a tree layout file explorer for Emacs                                   :noexport:

[[file:screenshots/screenshot.png]]

* Content                                                                            :TOC:noexport:
- [[#quick-feature-overview][Quick Feature Overview]]
   - [[#fancy-gifs][Fancy Gifs!]]
- [[#quick-start][Quick Start]]
- [[#detailed-feature-list][Detailed Feature List]]
   - [[#projects-and-workspaces][Projects and Workspaces]]
   - [[#conveniently-editing-your-projects-and-workspaces][Conveniently Editing Your Projects and Workspaces]]
   - [[#navigation-without-projects-and-workspaces][Navigation without Projects and Workspaces]]
   - [[#frame-locality][Frame Locality]]
   - [[#mouse-interface][Mouse Interface]]
   - [[#follow-mode][Follow-mode]]
   - [[#tag-follow-mode][Tag-follow-mode]]
   - [[#fringe-indicator-mode][Fringe-indicator-mode]]
   - [[#git-mode][Git-mode]]
   - [[#filewatch-mode][Filewatch-mode]]
   - [[#session-persistence][Session Persistence]]
   - [[#terminal-compatibility][Terminal Compatibility]]
   - [[#tag-view][Tag View]]
   - [[#current-directory-awareness][Current-Directory Awareness]]
   - [[#tramp-support][Tramp Support]]
   - [[#org-support][Org Support]]
   - [[#theme-support][Theme Support]]
   - [[#additional-packages][Additional Packages]]
   - [[#treemacs-as-a-framework][Treemacs as a Framework]]
- [[#installation][Installation]]
- [[#configuration][Configuration]]
   - [[#variables][Variables]]
   - [[#faces][Faces]]
   - [[#evil-compatibility][Evil compatibility]]
   - [[#customizing-themes-and-icons][Customizing Themes and Icons]]
- [[#keymap][Keymap]]
   - [[#unbound-functions][Unbound functions]]
   - [[#default-keymaps][Default keymaps]]
- [[#compatibility][Compatibility]]
- [[#faq][FAQ]]
- [[#contributing][Contributing]]
- [[#working-with-the-code-base][Working With The Code Base]]
- [[#dependencies][Dependencies]]

* Quick Feature Overview
Treemacs is a file and project explorer similar to NeoTree or vim's NerdTree, but largely inspired by the Project
Explorer in Eclipse. It shows the file system outlines of your projects in a simple tree layout allowing quick
navigation and exploration, while also possessing *basic* file management utilities. Specifically a quick feature
overview looks as follows:

 * Project management :: Treemacs lets you view multiple file trees - projects - at once and quickly add or remove them,
   and groups projects in workspaces.
 * Easy navigation :: quickly move between projects or use shortcuts to jump to parent or neighbouring nodes.
 * Versatile file access :: decide exactly how and where a file will be opened, including using ~ace-window~ to choose
   a window or launching an external application.
 * Understanding of frames :: every frame will receive its own treemacs buffer that will live and die with that frame.
 * Finding of files and tags :: Treemacs can follow along and keep in focus the currently selected file or even the tag
   at point using, either manually or automatically using either ~treemacs-follow-mode~ or ~treemacs-tag-follow-mode~.
 * Git Integration :: Treemacs can use different faces for files and directories based on their git status.
   The git process is run asynchronously, minimizing its performance impact.
 * [[https://github.com/deb0ch/emacs-winum][Winum]] & [[https://github.com/abo-abo/ace-window][ace-window]] compatibility :: The presence of treemacs will not interfere with winum's and ace-window's
   usual layouts.
 * [[https://github.com/bbatsov/projectile][Projectile]] integration :: the ~treemacs-projectile~ package lets you quickly add your projectile projects to the
   treemacs workspace.
 * Simple mouse interface :: Left clicks will work the same as you're used to from with graphical applications
 * Session persistence :: Treemacs automatically saves and restores your workspaces.
 * Dashing good looks :: Treemacs uses (optionally resizable) png images in HD 22x22 resolution for its icons (quantity
   is, of course, another matter). When run in a terminal a simple fallback is used.
 * Tag view :: Treemacs can display files' tags. All file types that Emacs can generate a (semantic) imenu index for are
   supported.
 * Visual feedback :: When it would otherwise be difficult to see the message in the minibuffer success/failure is
   indicated with pulse.el.
 * Theming support :: Treemacs supports using multiple icon themes that can be changed at will.
 * Ease of use :: Treemacs offers many configuration options, but comes with a set of (what hopefully should be) sane
   defaults. Installation aside there are two obligatory pieces of setup: 1) Choosing convenient keybindings to run
   treemacs and 2) If you use evil: requiring ~treemacs-evil~ to integrate treemacs with evil and enable j/k navigation.
   More on both below. You can also summon a helpful hydra with ~?~ that will remind you of treemacs' many keybindings
   and features.
 * Bookmark integration :: Running ~bookmark-set~ on a Treemacs item will store a bookmark to Treemacs buffer for that item.

** Fancy Gifs!

Various ways to open files:
[[file:screenshots/open-files.gif]]

Workspace administration with org-mode:
[[file:screenshots/workspace-edit.gif]]

Automatic reaction to changes in the file system:
[[file:screenshots/filewatch.gif]]

Automatic reaction to changes in git:
[[file:screenshots/git.gif]]

Full-featured mouse interface:
[[file:screenshots/mouse-interface.gif]]

Resizable icons:
[[file:screenshots/icon-resize.gif]]

* Quick Start
If you don't care about reading the full readme here's a list of some bare bones basics to get you started:
 * First of all: press ~?~ to summon the helpful hydra:
   [[file:screenshots/hydra.png]]
 * If you use evil don't forget to also install ~treemacs-evil~
 * If you use projectile you can install ~treemacs-projectile~ to allow quickly add your projectile projects to
   treemacs.
 * Treemacs doesn't bind any global keys, you need to use whatever fits you best. A full install setup can be found
   [[#installation][below]]. Otherwise just add a keybind for ~treemacs~.
 * For navigation use n/p (j/k when evil), M-n/M-p to move to same-height neighbour u to go to parent, and C-n/C-k to
   move between projects.
 * There's half a dozen different ways to open nodes, all bound under o as prefix. Pick your favourite.
 * TAB and RET are particularly configurable. See ~treemacs-TAB/RET-actions-config~.
 * Projects administration is bound under the ~C-c C-p~ prefix.

* Detailed Feature List
** Projects and Workspaces
If you've previously used a different explorer like NeoTree or NerdTree - or an earlier version of treemacs for that
matter - you are probably used to a display system wherein you see exactly a single file tree whose exact root you can
arbitrarily change. This system makes it difficult to work on and switch between multiple projects. Treemacs used to
(and still does) remedy that limitation by making every treemacs buffer unique to its frame, but it has now been
redesigned to be able to display multiple file trees - projects - at once.

In treemacs a workspace is simply a (named) collection of projects, while a project mostly consists of 2 things: its
location in the file system and its name. This is the info that you need to provide when you want to add a new project
to your workspace. Just like projects you can add, remove, rename and switch between workspaces at any time.

This design approach has various advantages and disadvantages. It is now no longer possible to "free roam" in the file
system with treemacs, i.e. you can no longer arbitrarily switch the single file tree's root to the directory at point or
the current root's parent. Another restriction is that the same part of the file system may not appear more than once as
part of the workspace. For example it is not possible to have both /Documents and /Documents/ProjectX as projects in the
same workspace, since internally treemacs heavily relies on every node having a unique natural key in its absolute path.
Nonetheless the pros certainly outweigh the cons, as a multiroot setup allows to work on multiple projects with any
combination concern/buffer separating frameworks, be it persp, eyebrowse, or projectile. It also opens the potential for
concurrent display not only of the file system, but e.g. the currently open buffers.
*** Workspace Selection
When a workspace is first needed, treemacs will select a workspace in the following manner:

If the current buffer is editing a file then treemacs will try to find the first workspace with a project containing
that file. If that fails treemacs will resort to using the /fallback workspace/ which is defined as simply the /first/
element in the list of all workspace.

The order of workspaces is the same that you see when calling ~treemacs-edit-workspaces~ (see next chapter). You can
interactively set the fall backback workspace by calling ~treemacs-set-fallback-workspace~.

This selection will happen when treemacs is first started (with a command like ~treemacs-select-window~) or when a
function that requires the current workspace to be known is used (like adding or removing a project).
** Conveniently Editing Your Projects and Workspaces
There are two ways to edit your projects and workspaces: call up single add/remove/rename/switch commands under either
the ~C-c C-p~ or ~C-c C-w~ prefix, or call ~treemacs-edit-workspaces~ and edit your entire layout in the form of a
single org-mode buffer.

The used org-format is quite simple: level 1 headlines are names of workspaces, level 2 headlines are names of projects
in a workspace, and every project's path is given as a description list, starting with a ~-~ (and an optional leading
space). Empty lines and lines starting with ~#~ are ignored, and everything else leads to an error.

You needn't worry about making mistakes either. If there's something wrong when you call ~treemacs-finish-edit~
(C-c C-c) then treemacs will point you at the incorrect line and tell you what's missing:

[[file:screenshots/workspace-edit.png]]

(Note that the list with the path property allows an indentation of 0 or 1 spaces only. The much greater visible
indentation is caused by ~org-indent-mode~)

** Navigation without Projects and Workspaces
If a strict workspace and project structure, as described above, is too stringent for your use-case you can, under
certain circumstances, use treemacs to freely navigate through your your file system, similar to dired: When your
workspace contains /exactly/ a single project you can use ~h~ and ~l~ (or ~treemacs-root-up~ and ~treemacs-root-down~) to
arbitrarily change the single project's root. ~h~ will navigate one level upward in the file system, ~l~ will move into
the directory at point.

** Frame Locality
Treemacs buffers have a limited scope they are visible in: the frames they are created in. A treemacs buffer, once
created, lives alongside and inside its frame, and is also destroyed with that frame. Calling ~treemacs~ while inside a
new frame will create a new buffer for it, regardless how many other treemacs buffers already exist. While there can be
multiple unique treemacs buffer they will all still show the same workspace and the same projects.

A treemacs buffer that does not belong to a frame may still be made visible by manually selecting in the buffer list.
This would break various assumptions in treemacs' code base and effectively falls under undefined behaviour - a bad idea
all around.

** Mouse Interface
Treemacs handles left clicks in much the same way as modern graphical applications do: a single click sets the focus, a
double click expands or collapses a directory or tag section node and visits a file/moves to a tag for a file/tag node.

Additionally tag sections can be expanded or collapsed by a single click on the file/tag section icon.

If you prefer to expand/collpase nodes with a single mouse click you can also use ~treemacs-single-click-expand-action~:

#+BEGIN_SRC emacs-lisp
  (define-key treemacs-mode-map [mouse-1] #'treemacs-single-click-expand-action)
#+END_SRC

A right click popup-menu is also available:

[[file:screenshots/right-click.png]]

You can also open a file in a specific window by dragging using left click from treemacs to the required window.

** Follow-mode
~treemacs-follow-mode~ is a global minor mode which allows the treemacs view to always move its focus to the currently
selected file. This mode runs on an idle timer - the exact duration of inactivity (in seconds) before a move is called
is determined by ~treemacs-tag-follow-delay~.

** Tag-follow-mode
~treemacs-tag-follow-mode~ is a global minor mode which extends and effectively replaces ~treemacs-follow-mode~. When
activated it follows not just the current file, but also the current tag. This works alongside treemacs' integration
with imenu, so all file types providing an imenu implementation are compatible.

This mode, like follow-mode, runs on an idle timer - the exact duration of inactivity (in seconds) before a move is
called is determined by ~treemacs-tag-follow-delay~.

Note that in order to move to a tag in treemacs the treemacs buffer's window needs to be temporarily selected, which
will reset ~blink-cursor-mode~'s timer if it is enabled. This will result in the cursor blinking seemingly pausing for a
short time and giving the appearance of the tag follow action lasting much longer than it really does.

** Fringe-indicator-mode
~treemacs-fringe-indicator-mode~ is a global minor mode that displays a little icon in the fringe that moves with the cursor.
It can make the selected line more visible if ~hl-line-mode~ doesn't stand out with your theme.
** Git-mode
~treemacs-git-mode~ is a global minor mode which enables treemacs to check for files' and directories' git status
information and highlight them accordingly (see also the ~treemacs-git-...~ faces). The mode is available in 3 variants:
~simple~, ~extended~ and ~deferred~:

 * The simple variant starts a git status process and parses its output in elisp. The parsing is kept quick and simple,
   so some info is missed: this version includes git status information only for files, but not directories.
 * The extended variant highlights both files and directories. This greatly increases the complexity and length of the
   parsing process, and is therefore done in an asynchronous python process for the sake of performance. The extended
   variant requires python3 to work.
 * The deferred variant is the same as extended, except the tasks of rendering nodes and highlighting them are
   separated. The former happens immediately, the latter after ~treemacs-deferred-git-apply-delay~ seconds of idle time.
   This may be faster (if not in truth then at least in appereance) as the git process is given a much greater amount of
   time to finish. The downside is that the effect of nodes changing their colors may be somewhat jarring, though this
   effect is largely mitigated due to the use of a caching layer.

 When called interactively ~treemacs-git-mode~ will ask for the variant to use. In lisp code an appropriate symbol can
 be directly passed to the minor mode function:

#+BEGIN_SRC emacs-lisp
  (treemacs-git-mode 'deferred)
#+END_SRC

All versions use an asynchronous git process and are optimized to not do more work than necessary, so their performance
cost should, for the most part, be the constant amount of time it takes to fork a subprocess. For repositories where
this is not the case ~treemacs-max-git-entries~ (default value 5000) will limit the number of git status entries
treemacs will process before ignoring the rest.

** Filewatch-mode
~treemacs-filewatch-mode~ is a global minor mode which enables treemacs to watch the files it is displaying for changes
and automatically refresh itself when it detects a change in the file system that it decides is relevant.

A change event is relevant for treemacs if a new file has been created or deleted or a file has been changed and
~treemacs-git-mode~ is enabled. Events caused by files that are ignored as per ~treemacs-ignored-file-predicates~ are
likewise counted as not relevant.

The refresh is not called immediately after an event was received, treemacs instead waits ~treemacs-file-event-delay~ ms
to see if any more files have changed to avoid having to refresh multiple times over a short period of time. Treemacs
will not refresh the entire view to make the detected changes visible, but will instead only make updates to the
directories where the change(s) happened. Using this mode is therefore by far not as expensive as a full refresh on
every change and save.

The mode only applies to directories opened *after* this mode has been activated. This means that to enable file
watching in an already existing treemacs buffer it needs to be killed and rebuilt. Turning off this mode is, on the
other hand, instantaneous - it will immediately turn off all existing file watch processes and outstanding refresh
actions.

_Known limitations_:
Staging and committing changes does not produce any file change events of its own, if you use ~treemacs-git-mode~ you
still need to do a manual refresh to see your files' faces go from 'changed' and 'untracked' to 'unchanged' after a
commit.

** Session Persistence
Treemacs' sessions - your workspace and the projects it contains - are saved when Emacs shuts down and restored when
treemacs is first loaded. This persistence process is fully automatic and independant, and should therefore be fully
compatible with ~desktop-save-mode~.

The persisted state is saved under ~user-emacs-directory/.cache/treemacs-persist~ by default. The exact file location
is saved in the variable ~treemacs-persist-file~.

If something goes wrong when loading the file the erroneous state will be saved in ~treemacs-last-error-persist-file~
for debugging.

** Terminal Compatibility
When run in a terminal treemacs will fall back to a much simpler rendering system, foregoing its usual png icons and
using simple ~+~ and ~-~ characters instead. The exact characters used are [[#custom-icons][highly customizable]].

** Tag View
Treemacs is able to display not only the file system, but also tags found in individual files. The tags list is sourced
using emacs' builtin imenu functionality, so all file types that emacs can generate an imenu index for are supported.

Imenu caches its result, so to avoid stale tag lists setting ~imenu-auto-rescan~ to t is recommended. Tags generated
with the help of ~semantic-mode~ are likewise supported.

*** ggtags

Treemacs can show the tags produced by ggtags if you switch a buffer's imenu index function to use ggtags:

#+BEGIN_SRC emacs-lisp
  (setq-local imenu-create-index-function #'ggtags-build-imenu-index)
#+END_SRC

** Current-Directory Awareness
Treemacs always sets the ~default-directory~ variable based on the (nearest) path at the current node, falling back to
your home directory when there is no node or path at point. That means that various commands like ~find-file~,
~magit-status~ or ~helm-projectile-ag~ will correctly act based on the current directory or project context.
** Tramp Support
Treemacs supports projects on remote directories, e.g. ~/scp:remote-server:path/to/directory~.

However tramp support has some restrictions: ~treemacs-use-collapsed-directories~ has no effect on remote directories.
** Org Support
Treemacs supports storing links to its file nodes by means of ~org-store-link~.
** Theme Support
Using a different treemacs theme works the same way as using a different Emacs theme: just call ~treemacs-load-theme~,
either programmatically or interactively. In the former case you need to supply the name of the theme as a string, like
this:

#+BEGIN_SRC emacs-lisp
  (treemacs-load-theme "Default")
#+END_SRC

Do keep in mind that by default treemacs' theme support is all theory: the standard installation includes only the
default theme; this feature is meant to easily allow *others* to extend, create and distribute themes for treemacs.

A detailed explanation on modifying themes and icons can be found in the [[#customizing-themes-and-icons][Configuration]] section.
** Additional Packages
Next to treemacs itself you can optionally install:

*** treemacs-evil
Must be installed and loaded if you use evil. The keybindings and the cursor will not be setup properly otherwise. It'll
also enable navigation with j/k instead of n/p.
*** treemacs-projectile
Allows to quickly add your projectile projects to the treemacs workspace.
*** treemacs-magit
A small utility package to fill the small gaps left by using filewatch-mode and git-mode in conjunction with magit: it
will inform treemacs about (un)staging of files and commits happening in magit.
*** treemacs-icons-dired
Allows you to use treemacs icons in dired buffers with ~treemacs-icons-dired-mode~:
[[file:screenshots/dired-icons.png]]
*** treemacs-persp
Integration with persp-mode that allows treemacs buffers to be unique inside the active perspective instead of the
default frame-based buffer scope.
** Treemacs as a Framework
Treemacs can be extended to display arbitrary nodes as well as be used as a general rendering backend for any tree-like
structures. [[file:Extensions.org][See here]] for an extended tutorial and demonstration.
* Installation
Treemacs is included in Spacemacs (for now only on the dev branch). If you are using the development version of
Spacemacs you can simply add treemacs to ~dotspacemacs-configuration-layers~ to replace the default NeoTree. Check ~SPC
h SPC treemacs~ for details. Otherwise you will need to add treemacs to ~dotspacemacs-additional-packages~.

Treemacs is also available on MELPA. If you just want to quickly start using it grab the ~use-package~ example below,
and customize it as needed (remove ~treemacs-evil~ if you don't use it, customize the keybindings to you taste, etc).

Either way keep in mind that treemacs has /no default keybindings/ for its globally callable initialization functions. Each
user is supposed to select keybindings for functions like ~treemacs-find-file~ based on whatever they find convenient.

You can find an exhaustive overview of all functions, their keybindings and functions you need to bind yourself [[#keymap][below]].

The following ~use-package~ snippet includes a list of /all/ of treemacs' configuration variables in their default
setting. Setting them all yourself is not necessary, they are only listed here to encourage discoverability.

#+BEGIN_SRC emacs-lisp
  (use-package treemacs
    :ensure t
    :defer t
    :init
    (with-eval-after-load 'winum
      (define-key winum-keymap (kbd "M-0") #'treemacs-select-window))
    :config
    (progn
      (setq treemacs-collapse-dirs                 (if treemacs-python-executable 3 0)
            treemacs-deferred-git-apply-delay      0.5
            treemacs-directory-name-transformer    #'identity
            treemacs-display-in-side-window        t
            treemacs-eldoc-display                 t
            treemacs-file-event-delay              5000
            treemacs-file-extension-regex          treemacs-last-period-regex-value
            treemacs-file-follow-delay             0.2
            treemacs-file-name-transformer         #'identity
            treemacs-follow-after-init             t
            treemacs-git-command-pipe              ""
            treemacs-goto-tag-strategy             'refetch-index
            treemacs-indentation                   2
            treemacs-indentation-string            " "
            treemacs-is-never-other-window         nil
            treemacs-max-git-entries               5000
            treemacs-missing-project-action        'ask
            treemacs-move-forward-on-expand        nil
            treemacs-no-png-images                 nil
            treemacs-no-delete-other-windows       t
            treemacs-project-follow-cleanup        nil
            treemacs-persist-file                  (expand-file-name ".cache/treemacs-persist" user-emacs-directory)
            treemacs-position                      'left
            treemacs-recenter-distance             0.1
            treemacs-recenter-after-file-follow    nil
            treemacs-recenter-after-tag-follow     nil
            treemacs-recenter-after-project-jump   'always
            treemacs-recenter-after-project-expand 'on-distance
            treemacs-show-cursor                   nil
            treemacs-show-hidden-files             t
            treemacs-silent-filewatch              nil
            treemacs-silent-refresh                nil
            treemacs-sorting                       'alphabetic-asc
            treemacs-space-between-root-nodes      t
            treemacs-tag-follow-cleanup            t
            treemacs-tag-follow-delay              1.5
            treemacs-user-mode-line-format         nil
            treemacs-width                         35)

      ;; The default width and height of the icons is 22 pixels. If you are
      ;; using a Hi-DPI display, uncomment this to double the icon size.
      ;;(treemacs-resize-icons 44)

      (treemacs-follow-mode t)
      (treemacs-filewatch-mode t)
      (treemacs-fringe-indicator-mode t)
      (pcase (cons (not (null (executable-find "git")))
                   (not (null treemacs-python-executable)))
        (`(t . t)
         (treemacs-git-mode 'deferred))
        (`(t . _)
         (treemacs-git-mode 'simple))))
    :bind
    (:map global-map
          ("M-0"       . treemacs-select-window)
          ("C-x t 1"   . treemacs-delete-other-windows)
          ("C-x t t"   . treemacs)
          ("C-x t B"   . treemacs-bookmark)
          ("C-x t C-t" . treemacs-find-file)
          ("C-x t M-t" . treemacs-find-tag)))

  (use-package treemacs-evil
    :after treemacs evil
    :ensure t)

  (use-package treemacs-projectile
    :after treemacs projectile
    :ensure t)

  (use-package treemacs-icons-dired
    :after treemacs dired
    :ensure t
    :config (treemacs-icons-dired-mode))

  (use-package treemacs-magit
    :after treemacs magit
    :ensure t)

  (use-package treemacs-persp
    :after treemacs persp-mode
    :ensure t
    :config (treemacs-set-scope-type 'Perspectives))
#+END_SRC

* Configuration
** Variables
Treemacs offers the following configuration options (~describe-variable~ will usually offers more details):

| Variable                               | Default                                          | Description                                                                                                                                                                                                                          |
|----------------------------------------+--------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| treemacs-indentation                   | 2                                                | The number of times each level is indented in the file tree. If specified as '(INTEGER px), indentation will be a single INTEGER pixels wide space.                                                                                  |
| treemacs-indentation-string            | " "                                              | The string that is used to create indentation when ~treemacs-indentation~ is not specified as pixels.                                                                                                                                |
| treemacs-width                         | 35                                               | Width of the treemacs window.                                                                                                                                                                                                        |
| treemacs-show-hidden-files             | t                                                | Dotfiles will be shown if this is set to t and be hidden otherwise.                                                                                                                                                                  |
| treemacs-follow-after-init             | nil                                              | When t follow the currently selected file after initializing the treemacs buffer, regardless of ~treemacs-follow-mode~ setting.                                                                                                      |
| treemacs-sorting                       | alphabetic-asc                                   | Indicates how treemacs will sort its files and directories. (Files will always be shown after directories.)                                                                                                                          |
| treemacs-ignored-file-predicates       | (treemacs--std-ignore-file-predicate)            | List of predicates to test for files and directories ignored by Emacs. Ignored files will *never* be shown in the treemacs buffer.                                                                                                   |
| treemacs-pre-file-insert-predicates    | nil                                              | List of predicates to test for files and directories not to be rendered. Unlike ~treemacs-ignored-file-predicates~ these predicates apply when files' git status information is available.                                           |
| treemacs-file-event-delay              | 5000                                             | How long (in milliseconds) to collect file events before refreshing. See also ~treemacs-filewatch-mode~.                                                                                                                             |
| treemacs-goto-tag-strategy             | refetch-index                                    | Indicates how to move to a tag when its buffer is dead.                                                                                                                                                                              |
| treemacs-default-visit-action          | treemacs-visit-node-no-split                     | Default action for opening a node (e.g. file, directory, tag). ~treemacs-visit-file-default~ action in ~treemacs-*-actions-config~ calls this function.                                                                              |
| treemacs-RET-actions-config            | Prefers visiting nodes over closing/opening      | Alist defining the behaviour of ~treemacs-RET-action~.                                                                                                                                                                               |
| treemacs-TAB-actions-config            | Prefers closing/opening nodes over visiting      | Alist defining the behaviour of ~treemacs-TAB-action~.                                                                                                                                                                               |
| treemacs-doubleclick-actions-config    | Closes/opens tags and visits files               | Alist defining the behaviour of ~treemacs-doubleclick-action~.                                                                                                                                                                       |
| treemacs-collapse-dirs                 | 0                                                | Collapse this many directories into one, when possible. A directory is collapsible when its content consists of nothing but another directory.                                                                                       |
| treemacs-silent-refresh                | nil                                              | When non-nil a completed refresh will not be announced with a log message. This applies both to manual refreshing as well as automatic (due to ~treemacs-filewatch-mode~).                                                           |
| treemacs-silent-filewatch              | nil                                              | When non-nil a refresh due to ~filewatch-mode~ will cause no log message.                                                                                                                                                            |
| treemacs-is-never-other-window         | nil                                              | Prevents treemacs from being selected with ~other-window~.                                                                                                                                                                           |
| treemacs-position                      | left                                             | Position of treemacs buffer. Valid values are ~left~, ~right~.                                                                                                                                                                       |
| treemacs-tag-follow-delay              | 1.5                                              | Delay in seconds of inactivity for ~treemacs-tag-follow-mode~ to trigger.                                                                                                                                                            |
| treemacs-tag-follow-cleanup            | t                                                | When non-nil ~treemacs-tag-follow-mode~ will keep only the current file's tags visible.                                                                                                                                              |
| treemacs-project-follow-cleanup        | nil                                              | When non-nil ~treemacs-follow-mode~ will keep only the current project expanded and all others closed.                                                                                                                               |
| treemacs-no-png-images                 | nil                                              | When non-nil treemacs will use TUI string icons even when running in a GUI.                                                                                                                                                          |
| treemacs-python-executable             | (treemacs--find-python3)                         | Python 3 binary used by treemacs.                                                                                                                                                                                                    |
| treemacs-recenter-after-file-follow    | nil                                              | Decides if and when to call ~recenter~ when ~treemacs-follow-mode~ moves to a new file.                                                                                                                                              |
| treemacs-recenter-after-tag-follow     | nil                                              | Decides if and when to call ~recenter~ when ~treemacs-tag-follow-mode~ moves to a new tag.                                                                                                                                           |
| treemacs-recenter-after-project-jump   | 'always                                          | Decides if and when to call ~recenter~ when navigating between projects.                                                                                                                                                             |
| treemacs-recenter-after-project-expand | 'on-distance                                     | Decides if and when to call ~recenter~ when expanding a project node.                                                                                                                                                                |
| treemacs-recenter-distance             | 0.1                                              | Minimum distance from window top/bottom (0.1 = 10%) before treemacs calls ~recenter~ in tag/file-follow-mode.                                                                                                                        |
| treemacs-pulse-on-success              | t                                                | When non-nil treemacs will pulse the current line as a success indicator, e.g. when creating a file.                                                                                                                                 |
| treemacs-pulse-on-failure              | t                                                | When non-nil treemacs will pulse the current line as a failure indicator, e.g. when failing to find a file's tags.                                                                                                                   |
| treemacs-elisp-imenu-expression        | [too large to list]                              | The imenu expression treemacs uses in elisp buffers.                                                                                                                                                                                 |
| treemacs-persist-file                  | ~/.emacs.d/.cache/treemacs-persist               | Path to the file treemacs uses to persist its state.                                                                                                                                                                                 |
| treemacs-last-error-persist-file       | ~/.emacs.d/.cache/treemacs-persist-at-last-error | Path to the file treemacs uses to persist its state.                                                                                                                                                                                 |
| treemacs-space-between-root-nodes      | t                                                | When non-nil treemacs will separate root nodes with an empty line.                                                                                                                                                                   |
| treemacs-wrap-around                   | t                                                | When non-nil treemacs will wrap around at the buffer edges when moving between lines.                                                                                                                                                |
| treemacs--fringe-indicator-bitmap      | [vertical bar]                                   | The fringe bitmap used by the fringe-indicator minor mode.                                                                                                                                                                           |
| treemacs-deferred-git-apply-delay      | 0.5                                              | Seconds of idle time for git highlighting to apply when using the deferred ~treemacs-git-mode~.                                                                                                                                      |
| treemacs-file-follow-delay             | 0.2                                              | Delay in seconds of idle time for treemacs to follow the selected window.                                                                                                                                                            |
| treemacs-display-in-side-window        | t                                                | When non-nil treemacs will use a dedicated [[https://www.gnu.org/software/emacs/draft/manual/html_node/elisp/Side-Windows.html][side-window]].                                                                                                                                                                              |
| treemacs-max-git-entries               | 5000                                             | Maximum number of git status entries treemacs will process. Anything above that number will be ignored.                                                                                                                              |
| treemacs-missing-project-action        | ask                                              | When a persisted project is missing from filesystem, ~ask~ will prompt for action, ~keep~ will keep the project in the project list, and ~remove~ will remove it from it without prompt.                                             |
| treemacs-show-cursor                   | nil                                              | When non-nil the cursor will stay visible in the treemacs buffer.                                                                                                                                                                    |
| treemacs-git-command-pipe              | ""                                               | Text to be appended to treemacs' git command. Useful for filtering with something like grep.                                                                                                                                         |
| treemacs-no-delete-other-windows       | t                                                | Prevents the treemacs window from being deleted by commands like ~delete-other-windows~ and ~magit-status~.                                                                                                                          |
| treemacs-eldoc-display                 | t                                                | Enables eldoc display of the file path at point. Requires ~eldoc-mode~.                                                                                                                                                              |
| treemacs-bookmark-title-template       | "Treemacs - ${project}: ${label}"                | When using ~bookmark-set~ in Treemacs, the default template for a bookmark label. The following patterns are available: "${project}", "${label}", "${label:N}", ${label-path}", "${label-path:N}", "${file-path}", "${file-path:N}". |
| treemacs-file-extension-regex          | Text after last period                           | Determines how treemacs detects a file extension. Can be set to use text after first or last period.                                                                                                                                 |
| treemacs-directory-name-transformer    | identity                                         | Transformer function that is applied to directory names before rendering for any sort of cosmetic effect.                                                                                                                            |
| treemacs-file-name-transformer         | identity                                         | Transformer function that is applied to file names before rendering for any sort of cosmetic effect.                                                                                                                                 |
| treemacs-user-mode-line-format         | nil                                              | When non-nil treemacs will use it as a mode line format (otherwise format provided by ~spaceline~, ~moody-mode-line~ and ~doom-modeline~ will be used or, finally, "Treemacs" text will be displayed)                                |
| treemacs-move-forward-on-expand        | nil                                              | When non-nil treemacs will move to the first child of an expanded node.                                                                                                                                                              |

** Faces
Treemacs defines and uses the following faces:
| Face                                   | Based on                                         | Description                                                                  |
|----------------------------------------+--------------------------------------------------+------------------------------------------------------------------------------|
| treemacs-directory-face                | font-lock-function-name-face                     | Face used for directories.                                                   |
| treemacs-directory-collapsed-face      | treemacs-directory-face                          | Face used for collapsed part of directories.                                 |
| treemacs-file-face                     | default                                          | Face used for files.                                                         |
| treemacs-root-face                     | font-lock-constant-face                          | Face used for project roots.                                                 |
| treemacs-root-unreadable-face          | treemacs-root-face                               | Face used for local unreadable project roots.                                |
| treemacs-root-remote-face              | font-lock-function-name-face, treemacs-root-face | Face used for readable remote (Tramp) project roots.                         |
| treemacs-root-remote-unreadable-face   | treemacs-root-unreadable-face                    | Face used for unreadable remote (Tramp) project roots.                       |
| treemacs-root-remote-disconnected-face | warning, treemacs-root-face                      | Face used for disconnected remote (Tramp) project roots.                     |
| treemacs-tags-face                     | font-lock-builtin-face                           | Face used for tags.                                                          |
| treemacs-help-title-face               | font-lock-constant-face                          | Face used for the title of the helpful hydra.                                |
| treemacs-help-column-face              | font-lock-keyword-face                           | Face used for the column headers of the helpful hydra.                       |
| treemacs-git-*-face                    | various font lock faces                          | Faces used by treemacs for various git states.                               |
| treemacs-term-node-face                | font-lock-string-face                            | Face for directory node symbols used by treemacs when it runs in a terminal. |
| treemacs-on-success-pulse-face         | :fg #111111 :bg #669966                          | Pulse face used when pulsing on a successful action.                         |
| treemacs-on-failure-puse-face          | :fg #111111 :bg #ab3737                          | Pulse face used when pulsing on a failed action.                             |

** Evil compatibility
To make treemacs get along with evil-mode you need to install and load ~treemacs-evil~. It does not define any functions
or offer any configuration options, making sure it is loaded is sufficient.

** Customizing Themes and Icons
*** Creating and Modifying Themes
Creating and modifying themes and icons is all done in a single step using dedicated macros.

To create a theme use ~treemacs-create-theme~. It requires the name of the theme and accepts 3 optional keyword
arguments: the directory the theme's icons are stored in (if it's using png icons), the name of the theme it's extending
and the config, a final form that's responsible for creating all the theme's icons. A config will typically consist of
nothing but calls to ~treemacs-create-icon~:

#+BEGIN_SRC emacs-lisp
  (treemacs-create-theme "Default"
    :icon-directory (f-join treemacs-dir "icons/default")
    :config
    (progn
      (treemacs-create-icon :file "root.png"   :fallback ""            :extensions (root))
      (treemacs-create-icon :file "emacs.png"  :fallback "🗏 "          :extensions ("el" "elc"))
      (treemacs-create-icon :file "readme.png" :fallback "🗏 "          :extensions ("readme.md"))
      (treemacs-create-icon :icon (all-the-icons-icon-for-file "yaml") :extensions ("yml" "yaml"))))
#+END_SRC

The ~:file~ argument is relative to the icon directory of the theme being created. When not using image icons the
~:icon-directory~ argument can be omitted and the ~:file~ argument can be switched for ~:icon~ to supply the icon string
directly. The TUI fallback is also optional, " " is used by default. Finally the list of extensions determines which
file extensions the icon should be used for.

For treemacs an extension is either the entire file name or the text after the last period (unless
~treemacs-file-extension-regex~ is customized). This means it can match normal file names like "init.el", extensionless
file names like "Makefile". Because the full name is checked first it is possible to give special files their own icon,
for example "Readme.md" can use a different icon than normal markdown files.

Instead of a string extension a symbol can also be used. In this case treemacs will also create a variable for that icon
named ~treemacs-icon-$symbol~. Treemacs uses several such icon variables and any new theme should define their own
versions (it it's not extending the default theme). The following icons are used:

 - root
 - dir-closed
 - dir-open
 - fallback
 - tag-open
 - tag-closed
 - tag-leaf
 - error
 - info
 - warning

Analogous to creating a new theme ~treemacs-modify-theme~ can be used to change, or add to, an existing theme:

#+BEGIN_SRC emacs-lisp
  (treemacs-modify-theme "Default"
    :icon-directory "/other/icons/dir"
    :config
    (progn
      (treemacs-create-icon :icon "+" :extensions (dir-closed))
      (treemacs-create-icon :icon "-" :extensions (dir-open))))
#+END_SRC

Finally keep in mind that treemacs' icons are all buffer-local values, and will most likely not be defined when trying
to access their values directly. When you need to programmatically access some of treemacs' icons you should use
~treemacs-get-icon-value~:

#+BEGIN_SRC emacs-lisp
  (treemacs-get-icon-value 'root nil "Default")
  (treemacs-get-icon-value "org" t)
#+END_SRC

*** Custom Icons

Treemacs also offers a quick and straighforward way to add a (gui) icon to the currently active theme, without caring
for its name or declaring icon directories:

#+BEGIN_SRC emacs-lisp
  (defvar treemacs-custom-html-icon (all-the-icons-icon-for-file "name.html"))
  (treemacs-define-custom-icon treemacs-custom-html-icon "html" "htm")
#+END_SRC


*Important*: There is a restriction that all icons must must be exactly 2 characters long. That's including the space
that will separate an icon from the filename.

**** Icons according to ~auto-mode-alist~
For some file extensions, like ".cc" or ".hh", it is not immediately obvious which major mode will open these files, and
thus which icon they should be assigned. Treemacs offers the option that automate this decision based on
~auto-mode-alist~. You can use the function ~treemacs-map-icons-with-auto-mode-alist~ to change the assigned icons for a
list of file extensions based on the major mode the icons are mapped to in ~auto-mode-alist~.

~treemacs-map-icons-with-auto-mode-alist~ takes 2 arguments: first a list of file extensions, then an alist that decides
which icon should be used for which mapped major mode. For example the code to decide the icons for ".hh" and ".cc"
files with ~auto-mode-alist~ would look like this:

#+BEGIN_SRC emacs-lisp
  (treemacs-map-icons-with-auto-mode-alist
   '(".cc" ".hh")
   '((c-mode   . (treemacs-get-icon-value "c"))
     (c++-mode . (treemacs-get-icon-value "cpp"))))
#+END_SRC

**** GUI vs TUI
It is possible to force treemacs to use the simple TUI icons in GUI mode by setting ~treemacs-no-png-images~ to t.

**** Resizing Icons
If your emacs has been compiled with imagemagick support you can arbitrarily change the size of treemacs' icons by
(interactively or programmatically) calling ~treemacs-resize-icons~.
*** Indent guide
Not really part of the icons, but a useful visual feature nonetheless: An indent guide like effect can be created by
selecting appropriate values for ~treemacs-indentation~ and ~treemacs-indentation-string~:

#+BEGIN_SRC emacs-lisp
  (setq treemacs-indentation-string (propertize " ⫶ " 'face 'font-lock-comment-face)
        treemacs-indentation 1)
#+END_SRC

* Keymap
** Unbound functions
These functions are not bound to any keys by default. It's left up to users to find the most convenient key binds.

| Action                                   | Description                                                                |
|------------------------------------------+----------------------------------------------------------------------------|
| treemacs                                 | Show/Hide/Initialize treemacs.                                             |
| treemacs-bookmark                        | Find a bookmark in treemacs.                                               |
| treemacs-find-file                       | Find and focus the current file in treemacs.                               |
| treemacs-find-tag                        | Find and focus the current tag in treemacs.                                |
| treemacs-select-window                   | Select the treemacs window if it is visible. Call ~treemacs~ if it is not. |
| treemacs-delete-other-windows            | Same as ~delete-other-windows~, but will not delete the treemacs window.   |
| treemacs-show-changelog                  | Opens a buffer showing the changelog.                                      |
| treemacs-load-theme                      | Load a different icon theme.                                               |
|------------------------------------------+----------------------------------------------------------------------------|
| treemacs-projectile                      | Add a project from projectile to treemacs.                                 |
| treemacs-add-and-display-current-project | Add current project to treemacs and open it.                               |
| treemacs-select-scope-type               | Select the scope of treemacs buffers in which they are unique              |

** Default keymaps

Treemacs' keybindings are distributed to several keymaps, based on common keybindings:

*** Project Keybinds (Prefix ~C-c C-p~)

| Key               | Action                                 | Description                                            |
|-------------------+----------------------------------------+--------------------------------------------------------|
| C-c C-p a         | treemacs-add-project-to-workspace      | Select a new project to add to the treemacs workspace. |
| C-c C-p p         | treemacs-projectile                    | Select a projectile project to add to the workspace.   |
| C-c C-p d         | treemacs-remove-project-from-workspace | Remove project at point from the workspace.            |
| C-c C-p r         | treemacs-rename-project                | Rename project at point.                               |
| C-c C-p c c       | treemacs-collapse-project              | Collapse project at point.                             |
| C-c C-p c o/S-TAB | treemacs-collapse-all-projects         | Collapse all projects.                                 |
| C-c C-p c o       | treemacs-collapse-all-projects         | Collapse all projects except the project at point.     |

*** Workspaces Keybinds (Prefix ~C-c C-w~)

| Key       | Action                          | Description                            |
|-----------+---------------------------------+----------------------------------------|
| C-c C-w r | treemacs-rename-workspace       | Rename a workspace.                    |
| C-c C-w a | treemacs-create-workspace       | Create a new workspace.                |
| C-c C-w d | treemacs-remove-workspace       | Delete a workspace.                    |
| C-c C-w s | treemacs-switch-workspace       | Switch the current workspace.          |
| C-c C-w e | treemacs-edit-workspaces        | Edit workspace layout via org-mode.    |
| C-c C-w f | treemacs-set-fallback-workspace | Select the default fallback workspace. |

*** Node Visit Keybinds (Prefix ~o~)

| Key    | Action                                           | Description                                                                                                    |
|--------+--------------------------------------------------+----------------------------------------------------------------------------------------------------------------|
| ov     | treemacs-visit-node-vertical-split               | Open current file or tag by vertically splitting ~next-window~.                                                |
| oh     | treemacs-visit-node-horizontal-split             | Open current file or tag by horizontally splitting ~next-window~.                                              |
| oo/RET | treemacs-visit-node-no-split                     | Open current file or tag, performing no split and using ~next-window~ directly.                                |
| oaa    | treemacs-visit-node-ace                          | Open current file or tag, using ace-window to decide which window to open the file in.                         |
| oah    | treemacs-visit-node-ace-horizontal-split         | Open current file or tag by horizontally splitting a window selected by ace-window.                            |
| oav    | treemacs-visit-node-ace-vertical-split           | Open current file or tag by vertically splitting a window selected by ace-window.                              |
| or     | treemacs-visit-node-in-most-recently-used-window | Open current file or tag in the most recently used window.                                                     |
| ox     | treemacs-visit-node-in-external-application      | Open current file according to its mime type in an external application. Linux, Windows and Mac are supported. |

*** Toggle Keybinds (Prefix ~t~)

| Key | Action                         | Description                                                                            |
|-----+--------------------------------+----------------------------------------------------------------------------------------|
| th  | treemacs-toggle-show-dotfiles  | Toggle the hiding and displaying of dotfiles.                                          |
| tw  | treemacs-toggle-fixed-width    | Toggle whether the treemacs window should have a fixed width. See also treemacs-width. |
| tf  | treemacs-follow-mode           | Toggle ~treemacs-follow-mode~.                                                         |
| ta  | treemacs-filewatch-mode        | Toggle ~treemacs-filewatch-mode~.                                                      |
| tv  | treemacs-fringe-indicator-mode | Toggle ~treemacs-fringe-indicator-mode~.                                               |

*** Copy Keybinds (Prefix ~y~)

| Key | Action                      | Description                                                       |
|-----+-----------------------------+-------------------------------------------------------------------|
| yy  | treemacs-copy-path-at-point | Copy the absolute path of the node at point.                      |
| yr  | treemacs-copy-project-root  | Copy the absolute path of the project root for the node at point. |
| yf  | treemacs-copy-file          | Copy the file at point.                                           |

*** General Keybinds

| Key      | Action                                      | Description                                                                                            |
|----------+---------------------------------------------+--------------------------------------------------------------------------------------------------------|
| ?        | treemacs-helpful-hydra                      | Summon the helpful hydra to show you the treemacs keymap.                                              |
| j/n      | treemacs-next-line                          | Go to the next line.                                                                                   |
| k/p      | treemacs-previous-line                      | Go to the previous line.                                                                               |
| M-J/N    | treemacs-next-line-other-window             | Go to the next line in ~next-window~.                                                                  |
| M-K/P    | treemacs-previous-line-other-window         | Go to the previous line in ~next-window~..                                                             |
| <PgUp>   | treemacs-next-page-other-window             | Go to the next page in ~next-window~.                                                                  |
| <PgDn>   | treemacs-previous-page-other-window         | Go to the previous page in ~next-window~..                                                             |
| M-j/M-n  | treemacs-next-neighbour                     | Go to the next same-level neighbour of the current node.                                               |
| M-k/M-p  | treemacs-previous-neighbour                 | Go to the previous same-level neighbour of the current node.                                           |
| u        | treemacs-goto-parent-node                   | Go to parent of node at point, if possible.                                                            |
| <M-Up>   | treemacs-move-project-up                    | Switch positions of project at point and the one above it.                                             |
| <M-Down> | treemacs-move-project-down                  | Switch positions of project at point and the one below it.                                             |
| w        | treemacs-set-width                          | Set a new value for the width of the treemacs window.                                                  |
| RET      | treemacs-RET-action                         | Run the action defined in ~treemacs-RET-actions-config~ for the current node.                          |
| TAB      | treemacs-TAB-action                         | Run the action defined in ~treemacs-TAB-actions-config~ for the current node.                          |
| g/r/gr   | treemacs-refresh                            | Refresh the project at point.                                                                          |
| d        | treemacs-delete                             | Delete node at point.                                                                                  |
| R        | treemacs-rename                             | Rename node at point.                                                                                  |
| cf       | treemacs-create-file                        | Create a file.                                                                                         |
| cd       | treemacs-create-dir                         | Create a directory.                                                                                    |
| q        | treemacs-quit                               | Hide the treemacs window.                                                                              |
| Q        | treemacs-kill-buffer                        | Delete the treemacs buffer.                                                                            |
| P        | treemacs-peek                               | Peek at the file (or tag) at point without fully opening it.                                           |
| yy       | treemacs-copy-path-at-point                 | Copy the absolute path of the node at point.                                                           |
| yr       | treemacs-copy-project-root                  | Copy the absolute path of the project root for the node at point.                                      |
| yf       | treemacs-copy-file                          | Copy the file at point.                                                                                |
| m        | treemacs-move-file                          | Move the file at point.                                                                                |
| s        | treemacs-resort                             | Set a new value for ~treemacs-sorting~.                                                                |
| b        | treemacs-add-bookmark                       | Bookmark the currently selected files's, dir's or tag's location.                                      |
| h        | treemacs-root-up                            | Move treemacs' root one level upward. Only works with a single project in the workspace.               |
| l        | treemacs-root-down                          | Move treemacs' root into the directory at point. Only works with a single project in the workspace.    |
| H        | treemacs-collapse-parent-node               | Collapse the parent of the node at point.                                                              |
| \!       | treemacs-run-shell-command-for-current-node | Run an asynchronous shell command on the current node, replacing "$path" with its path.                |
| M-!      | treemacs-run-shell-command-in-project-root  | Run an asynchronous shell command in the root of the current project, replacing "$path" with its path. |

* Compatibility
The correctness of treemacs' display behaviour is, to a large degree, ensured through window properties and reacting to
changes in the window configuration. The packages most likely to cause trouble for treemacs are therefore those that
interfere with Emacs' buffer spawning and window splitting behaviour. Treemacs is included in Spacemacs and I am a
Spacemacs user, therefore treemacs guarantees first-class support & compatibility for window-managing packages used in
Spacemacs, namely [[https://github.com/Bad-ptr/persp-mode.el][persp]], [[https://github.com/wasamasa/eyebrowse][eyebrowse]], [[https://github.com/m2ym/popwin-el][popwin]] and [[https://github.com/bmag/emacs-purpose][window-purpose]], as well as [[https://github.com/wasamasa/shackle][shackle]]. For everything else there may be
issues and, depending on the complexity of the problem, I may decide it is not worth fixing.

Aside from this there are the following known incompatibilities:

 * Any package invoking ~font-lock-ensure~ in the treemacs buffer. This will reset the faces of treemacs' buttons (once)
   and is a known [[https://debbugs.gnu.org/cgi/bugreport.cgi?bug=28599][emacs bug]].
 * A possible cause of this issue using an old version of swiper.
 * Rainbow mode activated in treemacs will likewise produce this behaviour. Make sure not to include rainbow-mode as
   part of ~special-mode-hook~, since this is the mode ~treemacs-mode~ is derived from.

* FAQ
 * How do I hide files I don't want to see?

   You need to define a predicate function and add it to ~treemacs-ignored-file-predicates~. This function accepts two
   arguments, a file's name and its absolute path, and must return non-nil when treemacs should hide that file.

   For example the code to ignore files eiter called "foo" or located in "/x/y/z/" would look like this:

   #+BEGIN_SRC emacs-lisp
     (with-eval-after-load 'treemacs

       (defun treemacs-ignore-example (filename absolute-path)
         (or (string-equal filename "foo")
             (string-prefix-p "/x/y/z/" absolute-path)))

       (add-to-list 'treemacs-ignored-file-predicates #'treemacs-ignore-example))
   #+END_SRC

 * How do I keep treemacs from showing files that are ignored by git?

   Short answer:

   #+BEGIN_SRC emacs-lisp
     (with-eval-after-load 'treemacs
       (add-to-list 'treemacs-pre-file-insert-predicates #'treemacs-is-file-git-ignored?))
   #+END_SRC

   A slightly longer explanation about how you can hook into the render process can be found in the documentation string
   of ~treemacs-pre-file-insert-predicates~.

 * Why am I seeing no file icons and only +/- for directories?

   Treemacs will permanently fall back on its simple TUI icons if it detects that the emacs instance it is run in cannot
   create images. You can test this by evaluating ~(create-image "" 'png)~. If this code returns an error like "Invalid
   image type ´png´" your emacs does not support images.

 * How do I get treemacs to stop telling me when it's been refreshed, especially with filewatch-mode?

   See ~treemacs-silent-refresh~ and ~treemacs-silent-filewatch~.

 * ENOSPC / No space left on device

   You may run into this error when you use filewatch-mode. The solution is to increase the number of allowed user
   watches, as described in [[https://stackoverflow.com/questions/16748737/grunt-watch-error-waiting-fatal-error-watch-enospc][this link]]. You'll also want to see what's responsible for setting all those file watches in
   the first place, since treemacs only watches the directories it is displaying and so won't produce more than a couple
   dozen watches at best.

 * Why is treemacs warning me about not being able to find some background colors and falling back to something else?

   Treemacs needs those colors to make sure that background colors of its icons correctly align with hl-line-mode. Png
   images' backgrounds are not highlighted by hl-line-mode by default, treemacs is manually correcting this every time
   hl-line's overlay is moved. To make that correction work it needs to know two colors: the current theme's ~default~
   background, and its ~hl-line~ background color. If treemacs cannot find hl-lines's background color it falls back to
   the default background color. If it cannot even find the default background it will fall back to #2d2d31. The
   warnings serve to inform you of that fallback.

   If your theme does not define a required color you can set it yourself before treemacs loads like this:

   #+BEGIN_SRC emacs-lisp
     (set-face-attribute 'hl-line nil :background "#333333")
   #+END_SRC

   If you just want to disable the warnings you can do so by defining the variable ~treemacs-no-load-time-warnings~. Its
   exact value is irrelevant, all that matters is that it exists at all. Since the warnings are issues when treemacs is
   first being loaded the variable must be defined *before* treemacs is initialized. This is best achieved by adding the
   line ~(defvar treemacs-no-load-time-warnings t)~ to treemacs' use-package ~:init~ block.

 * Can I expand *everything* under a node?

   Yes, you just need to expand it with a [[https://www.emacswiki.org/emacs/PrefixArgument][prefix argument]]. Closing nodes with a prefix argument works as well. In this
   case treemacs will forget about the nodes opened below the one that was closed and not reopen them automatically.

* Contributing
Contributions are very much welcome, but should fit the general scope and style of treemacs. The following is a list of
guidelines that should be met (exceptions confirm the rule):

 - There should be one commit per feature.
 - Commit messages should start with a note in brackets that roughly describes the area the commit relates to, for
   example ~[Icons]~ if you add an icon.
 - Code must be in the right place (what with the codebase being split in many small files). If there is no right place
   it probably goes into treemacs-core-utils.el which is where all the general implementation details go.
 - New features must be documented in the readme (for example mentioning new config options in the [[#variables][Config Table]]).
 - There must not be any compiler warnings.
 - The test suite must pass.

Treemacs uses cask to setup a local testing environment and a Makefile that simplifies compiling and testing the
codebase. First run ~cask install~ to locally pull treemacs' dependencies. Then you can use the following Makefile
targets:

 - make prepare :: Downloads and updates Cask's dependencies. Is a dependency of the ~test~ and ~compile~ targets.
 - make compile :: Compiles the code base (and treats compiler warnings as errors).
 - make clean :: Removes the generated .elc files.
 - make lint :: Runs first ~compile~ then ~clean~, even if the former fails.
 - make test :: Runs the testsuite, once in a graphical environment and once in the terminal.

Finally if you want to just add an icon you can take [[https://github.com/Alexander-Miller/treemacs/commit/94df3e36af865dab2c76b549b1a61f418e3bf5be][this commit]] as an example (though the icons have since been moved
into their own module in ~treemacs-icons.el~).

* Working With The Code Base

If you want to delve into the treemacs' code base, check out [[https://github.com/Alexander-Miller/treemacs/wiki][the wiki]] for some general pointers.

* Dependencies
 * emacs >= 25.2
 * f.el
 * s.el
 * dash
 * cl-lib
 * ace-window
 * pfuture
 * ht
 * hydra
 * (optionally) evil
 * (optionally) projectile
 * (optionally) winum
 * (optionally) python(3)
