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Emacs Mac Port Introduction

on emacs, emacs-mac-port

Valuable Features & Improvements

The Emacs Mac Port is an excellent distribution of Emacs which greatly improves Emacs’ functionality on macOS. It adds native GUI support which provides a slew of nice features. I would like to name some of those features which I particularly enjoy, so please note that this is not a full list of the features and improvements. If you would like a full list, check out the README file which is well worth your time if you use macOS and Emacs. The following items are taken from there, so again, if it looks like something is missing, then please look at the full list because these are just my favorite features:

  • Better C-g handling

  • It doesn’t use CPU time while the Lisp interpreter is idle and waiting for some events to come, even with subprocesses or network connections.

  • Graceful termination: If you try logout/shutdown/reboot while leaving a file-visiting buffer modified and unsaved, a popup window appears for confirmation. If you cancel the termination of Emacs (including C-g or ESC), the whole logout/shutdown/reboot process is also canceled immediately (i.e., you will see a “canceled” dialog immediately rather than a “timed out” one afterward). If you don’t have unsaved buffers, shell buffers, etc., you won’t see unnecessary confirmation.

  • Apple event handling: One can define Apple event handlers at the Lisp level. Actually, graceful termination above is an instance of Lisp-level Apple event handling. Another example is “Get URL” handler that enables us to invoke the mailer you customized with mail-user-agent, e.g.,

$ osascript -e 'tell application "Emacs" to open location "mailto:foo@example.com"'

If you set Emacs as the default mailer via Mail.app preference, the Emacs mailer will set up a draft buffer when you click a mailto: link in a Web browser.

  • DictionaryService support: You can look up a word under the mouse pointer in the selected window by typing Command-Control-D (or double/single-tapping a trackpad with three fingers on Mac OS X 10.7/10.8, resp.).

  • Some minor visual enhancements

    • Aligned key bindings in menus
    • Progress indicator (corresponding to hourglass) in the title bar
    • Unusable items in the font panel are hidden

  • The fullscreen frame parameter, with all values supported: fullboth, fullwidth, fullheight, and maximized. The fullboth frames, which don’t have the title bar, still allow us to access the menu bar, the Dock, and the tool bars. The menu bar can also be activated via menu-bar-open, Control-F2 (if full keyboard access enabled), or Command-Shift-/ (on Mac OS X 10.5 and later) even for fullboth frames where the menu bar is usually hidden. Changing fonts or internal-border-width in fullscreen frames does not clutter display. On multiple monitor environments, one can move fullscreen frames to another monitor by setting the left and top frame parameters accordingly. Attaching/detaching external monitors should work even with fullscreen frames.

  • The sticky frame parameter, which allows us to keep particular frames visible for all Spaces on Mac OS X 10.5 and later.

  • The function system-move-file-to-trash, which can be specified as a value of delete-by-moving-to-trash.

  • SVG image display. This can be done via the WebKit framework, so you don’t need librsvg.

  • Unicode character display including non-BMP ones.

  • Complex Text Layout and text shaping. They are implemented using the Core Text or NS Text layout engine, so you don’t need libotf.

  • Can be compiled with the ImageMagick support. Even without the ImageMagick library, the Mac port provides a fallback using the Image I/O framework so you can scale and rotate images.

  • The variable tool-bar-style works like in GTK+. The values both-horiz, text-image-horiz are synonymous with both.

  • Horizontal scroll bar support.

  • Pixel-based mouse wheel smooth scroll for newer mice/trackpads.

  • Gesture event handling for newer trackpads. By default, pinch out/in are bound to text size scaling. With the shift key, they turn on/off fullscreen status of the frame.

  • “Click in the scroll bar to: Jump to the spot that’s clicked” setting in the System Preferences is supported. Pressing the option key while clicking toggles this behavior temporarily.

  • Change of text smoothing threshold setting in the Appearance pane of the System Preferences is reflected immediately.

  • Several keyboard shortcuts (notably those for Keyboard Navigation) listed in System Preferences just work like other applications.

  • When the clipboard has both textual and image data, yank inserts the former and push both into the kill ring so the latter can be inserted with yank-pop afterwards.

  • Can display color bitmap fonts such as Apple Color Emoji, if compiled and executed on Mac OS X 10.7 or later. Also supports display of some combinations of regional indicator symbols, such as U+1F1EF followed by U+1F1F5, as national flags. Variation Selectors 15 (text-style) and 16 (emoji-style) are also supported. On OS X 10.10.3 and later, emoji modifiers for skin tones (U+1F3FB - U+1F3FF) are supported as well.

  • New function `mac-start-animation’, which provides animation effects on Mac OS 10.5 and later via Core Animation. You can see the default animations with buffer switching by horizontal swiping/flicking, exiting from the splash screen by typing “q”, and the “About Emacs” and “Preferences…” menu items in the application menu (labeled “Emacs”) in the menu bar.

  • High-resolution image display support for Retina displays. Dynamic resolution change is also supported. For bitmap formats, high-resolution data can be specified either by the “\@2x” file name convention, the “:data-2x” property, or multi-image TIFF. Shrinking a large image with the “imagemagick” (or Mac-specific “image-io”) image type also works but gives a non-optimal result on dynamic resolution change. For vector formats, images are automatically re-rendered according to the resolution of the frame. DocView mode and LaTeX fragment preview in Org mode are modified so they can take advantage of this feature.

At the time of this writing, it is more than just an improvement; it lacks a bug in the official NS Port which breaks menus on Mojave. Suffice it to say, the Emacs Mac Port is my current choice of Emacs distro and the best choice I’ve seen for macOS (Aquamacs is another good one, but unfortunately it does not integrate with the native macOS GUI and its changes only exist at the Lisp level).

The only problem it has is lack of multi-tty support, but I managed to fix this issue which I documented here.

History & Future

The Emacs Mac Port is developed and maintained by Mitsuharu Yamamoto and it regularly pulls changes from GNU Emacs proper, thus staying up-to-date with it. It exists as a fork because at the time of its initial release, it wasn’t quite ready so the Emacs developers chose the so-called NS Port instead (which is now technically inferior). Why is it called the NS Port? Because Emacs historically preferred the term “Nextstep”, presumably due to a desire to support GNUstep. The maintainer of the NS Port acknowledged that the Mac Port does a better job in a number of areas:

The Mac port has a better maintainer than me, who knows the toolkit and things better than I could ever hope to. It ties into macOS better (I use very little macOS specific software, and the whole ‘services’ thing is a mystery to me, for example). It doesn’t have the Mojave redraw problems that have me completely scunnered at the moment. It handles concurrency better. It is simply better maintained.

Yet its use of features not supported by GCC might rule it out as a replacement candidate:

But then again, the Mac port makes use of things that gcc doesn’t support, like ObjC blocks, so that would probably rule it out as an official port immediately.

The duplication of effort to maintain two ports seems like a waste to me, but there are definitely barriers to joining forces and having only one, official, port.

This could cause Richard Stallman to be against merging the Mac Port in place of the NS Port because he wants GNU projects to use GCC. He may also object to it if he perceives that it supports features not found on Linux, as he has been known to raise such issues in the past.

I think it is too bad that the Mac Port has not yet replaced the NS Port because it is superior with its native macOS integration. The developer has clearly worked hard and his work is praiseworthy. I hope the Emacs developers do not allow the aforementioned issues to be obstacles which disallow the Mac Port from merging into the Emacs source code.