Archive for March, 2015

When using Emacs on a larger screen where Emacs’ frame is split into multiple windows, you sometimes wish there was some simple way to rearrange which buffer is shown in which window. ¬†Of course, you can do that by moving through your windows and using switch-to-buffer and friends but that’s not really convenient.

So here’s a command which lets you use drag one buffer from one window to the other. The effect is that the buffers of the start and target window are swapped.

(defun th/swap-window-buffers-by-dnd (drag-event)
  "Swaps the buffers displayed in the DRAG-EVENT's start and end
window."
  (interactive "e")
  (let ((start-win (cl-caadr drag-event))
        (end-win   (cl-caaddr drag-event)))
    (when (and (windowp start-win)
               (windowp end-win)
               (not (eq start-win end-win))
               (not (memq (minibuffer-window)
                          (list start-win end-win))))
      (let ((bs (window-buffer start-win))
            (be (window-buffer end-win)))
        (unless (eq bs be)
          (set-window-buffer start-win be)
          (set-window-buffer end-win bs))))))

Bind it to some mouse drag event and have fun. For example, I use (global-set-key (kbd "<C-S-drag-mouse-1>") #'th/swap-window-buffers-by-dnd) so that drag’n’drop with the left mouse button and control and shift pressed is bound to the command above.