Emacs: Create A Dedicated Buffer Frame

Aug 12, 2025 by Pedro Alvarez 39 views

Creating a Dedicated Frame for a Specific Buffer in Emacs

Hey guys! Ever find yourself juggling multiple buffers in Emacs and wishing you could dedicate a specific frame to a particular buffer? Like, a frame that always shows your Org-mode agenda, or your project's README, and pops into focus whenever you need it? Well, you're in luck! This is totally achievable in Emacs, and we're gonna break down how to do it.

Understanding the Goal: Dedicated Frames and Buffer Display

So, what's the core idea here? We want to create a dedicated frame – think of it as a separate window that Emacs manages independently. This frame will be the permanent home for a specific buffer. Now, whenever you try to display that buffer (whether by opening the file, switching to it with C-x b, or any other means), Emacs shouldn't open a new window or bury it somewhere in your existing frame setup. Instead, it should bring our dedicated frame to the forefront and show the buffer there. This is super useful for things you frequently reference and want to keep visible without the hassle of constantly rearranging windows.

Key Concepts: Frames, Windows, and Buffers

Before we dive into the code, let's quickly clarify the terminology. In Emacs:

Frames are the top-level windows you see on your screen. You can have multiple Emacs frames open, each acting like a separate instance of the editor.
Windows are the panes within a frame. A single frame can be split into multiple windows, each displaying a different buffer or view.
Buffers are the in-memory representations of your files or other content (like the Messages buffer, or an Org-mode agenda).

Our goal is to create a frame, and within that frame, a window that's dedicated to a specific buffer. This means we'll be manipulating both frames and windows, making sure they behave the way we want.

Why Use a Dedicated Frame?

You might be thinking, "Why not just use a regular window?" Good question! Dedicated frames offer a few key advantages:

Persistence: The frame will always be there, even if you close the window displaying the buffer. This ensures your buffer's "home" is always ready.
Focus Management: We can make sure that displaying the buffer always brings the frame into focus, saving you the effort of manually switching to it.
Cleanliness: Dedicated frames help keep your main Emacs frame uncluttered. You can reserve it for your primary editing tasks, while secondary buffers live in their own space.

Step-by-Step Implementation: Elisp to the Rescue!

Alright, let's get our hands dirty with some Emacs Lisp (Elisp). We'll create a function that does the following:

Checks if the dedicated frame already exists.
If it doesn't exist, creates a new frame and displays the buffer in it.
If it does exist, brings the frame into focus and displays the buffer.

Here's the code:

(defun my/display-buffer-in-dedicated-frame (buffer-or-name frame-name)
  "Display BUFFER-OR-NAME in a dedicated frame named FRAME-NAME.
  If the frame doesn't exist, create it. If it does, focus it."
  (let ((buffer (if (stringp buffer-or-name)
                  (find-buffer buffer-or-name)
                buffer-or-name))
        (frame (or (get-frame frame-name)
                   (make-frame `((name . ,frame-name))))))
    (select-frame frame)
    (display-buffer buffer frame)))

(defun my/dedicated-frame-function (buffer-name frame-name)
  "Function to create or focus a dedicated frame for BUFFER-NAME."
  (interactive
   (list (read-buffer "Buffer name: " (buffer-name))
         (read-string "Frame name: " "Dedicated Frame")))
  (my/display-buffer-in-dedicated-frame buffer-name frame-name))

(defun my/focus-dedicated-frame (buffer-name frame-name)
  "Focus the dedicated frame for BUFFER-NAME if it exists."
  (interactive
   (list (read-buffer "Buffer name: " (buffer-name))
         (read-string "Frame name: " "Dedicated Frame")))
  (let ((buffer (find-buffer buffer-name))
        (frame (get-frame frame-name)))
    (if (and buffer frame)
        (progn
          (select-frame frame)
          (display-buffer buffer frame))
      (message "Dedicated frame not found."))))

Let's break this down piece by piece:

The `my/display-buffer-in-dedicated-frame` Function

This is the heart of our solution. It takes two arguments:

buffer-or-name: The buffer we want to display. This can be either the buffer object itself or its name as a string.
frame-name: A string that will be used as the name of our dedicated frame. This is important for identifying the frame later.

Inside the function, we first use let to define two local variables:

buffer: We use if and stringp to check if buffer-or-name is a string. If it is, we use find-buffer to get the actual buffer object. Otherwise, we assume it's already a buffer object.
frame: This is where the magic happens. We use or to check if a frame with the given frame-name already exists using get-frame. If it does, we use that frame. If not, we create a new frame using make-frame and set its name parameter. This ensures we either reuse an existing frame or create a new one if needed.

Next, we use select-frame to bring our frame to the front and make it the selected frame. Finally, we use display-buffer to display the buffer in our dedicated frame. This is the function that actually shows the buffer in the window.

The `my/dedicated-frame-function` Function

This function is designed to be called interactively (i.e., by you, the user). The (interactive ...) form tells Emacs how to gather the arguments from the user.

In this case, we're using read-buffer to prompt the user for the buffer name, using the current buffer's name as the default. We're also using read-string to prompt for the frame name, with "Dedicated Frame" as the default.

Once we have the buffer name and frame name, we simply call our my/display-buffer-in-dedicated-frame function to do the actual work.

The `my/focus-dedicated-frame` Function

This function provides a way to focus on an existing dedicated frame without necessarily creating a new one if it doesn't exist. It's useful if you just want to bring the frame to the front.

It also uses (interactive ...) to prompt the user for the buffer name and frame name. It then uses find-buffer and get-frame to find the buffer and frame, respectively.

If both the buffer and frame are found, it uses select-frame to focus the frame and display-buffer to display the buffer in it. If either the buffer or frame is not found, it displays a message in the minibuffer.

Putting It All Together: Configuration and Usage

Now that we have the code, let's integrate it into your Emacs configuration. Open your ~/.emacs or ~/.emacs.d/init.el file and add the code snippet we discussed earlier.

Add Keys to Call Function

To make these functions easy to use, you'll want to bind them to keys. For example, you could add the following to your init file:

(global-set-key (kbd "C-c d") #'my/dedicated-frame-function)
(global-set-key (kbd "C-c f") #'my/focus-dedicated-frame)

This binds C-c d to my/dedicated-frame-function and C-c f to my/focus-dedicated-frame. You can, of course, choose any keybindings you prefer.

Using the Functions

With the code in your init file and the keybindings set, you're ready to go! Here's how to use the functions:

Press M-x my/dedicated-frame-function RET (or your chosen keybinding, like C-c d).
Emacs will prompt you for the buffer name. Enter the name of the buffer you want to display in a dedicated frame (e.g., *scratch*, my-project/README.md, or the name of your Org-mode agenda buffer).
Emacs will then prompt you for the frame name. You can use something descriptive, like "Scratch Frame" or "Agenda Frame". If a frame with this name already exists, it will be used; otherwise, a new frame will be created.

Now, whenever you try to display that buffer, Emacs will automatically bring your dedicated frame into focus. It's like magic!

If you just want to focus on the dedicated frame (without necessarily displaying a specific buffer if it's not already displayed), you can use M-x my/focus-dedicated-frame RET (or your chosen keybinding, like C-c f).

Customization and Further Enhancements

The code we've written is a great starting point, but there's plenty of room for customization. Here are a few ideas:

Frame Parameters: You can customize the appearance and behavior of the dedicated frame when it's created. For example, you could set its size, position, or window manager decorations. Check the documentation for make-frame for the available options.
```
(make-frame `((name . ,frame-name) (width . 80) (height . 25)))
```
Buffer-Specific Frames: You could create a function that automatically sets up dedicated frames for specific buffers based on their names or file extensions. This would save you the trouble of manually creating the frames each time.
Integration with Project Management: If you use a project management package like Projectile, you could automatically create dedicated frames for project-specific buffers (e.g., the project's README or a notes file).
Automatically Focus on Buffer Display: You might want to modify the display-buffer-alist to automatically use your dedicated frame function whenever a specific buffer is displayed. This eliminates the need to manually call the function.
```
(add-to-list 'display-buffer-alist
             `(
```