Magic Trackpad desk setup: volume and brightness without keys

A Magic Trackpad doesn't have any built-in gesture for volume or brightness, and with most third-party monitors macOS can't change the monitor's brightness at all. The built-in fix for volume is the Sound slider in Control Centre. For a proper desk setup, an app like Slidr turns the Magic Trackpad's right edge into volume and its left edge into brightness, including DDC-capable external monitors.

This post is for one particular setup: a MacBook closed on a stand, or a Mac mini or Mac Studio, with a big monitor and a Magic Trackpad. It's a lovely way to work until you want to turn something up.

What does macOS give you on a desktop setup?

Volume is easy enough with a keyboard: Apple's Magic Keyboard has volume keys in the top row. Without reaching for it, you're down to Control Centre's Sound slider, or the Sound control added to the menu bar (Apple's Control Centre guide explains how to add items to the menu bar).

Brightness depends on the monitor. Apple's support article on dark external displays puts it plainly: if your keyboard and external display are made by Apple, the brightness keys and the Displays slider work. If the display isn't made by Apple, "you might need to use its built-in controls and menu system to adjust brightness". In other words, the joystick on the back of the monitor.

There's one more built-in option. Apple's keyboard shortcuts list includes Control-Brightness Up or Down to "change the brightness of your external display, if supported by your display". Worth a try. On many third-party monitors it does nothing.

Why does a Magic Trackpad make this more awkward?

On a laptop, the keys are inches away from the trackpad. At a desk, the keyboard might be pushed back, or tucked away while you're reading, editing photos or on a call. The trackpad is the thing your hand is already on.

The Magic Trackpad is also big, and its edges are easy to find without looking. That makes it a good surface for edge gestures.

How do I get volume and brightness on the Magic Trackpad?

Slidr is a menu bar app for macOS 12 or later. It works with a MacBook's built-in trackpad or a Magic Trackpad, and the gestures are the same on both: slide one finger up or down the right edge for volume, and up or down the left edge for brightness.

Setup is: download from the download page, drag to Applications, open it, then allow Accessibility access in System Settings. The Magic Trackpad guide has the details and a short troubleshooting section.

For the external monitor, one extra step: open the Slidr menu and turn on External Monitor Brightness. It's off by default. Once on, the left edge controls the monitor your cursor is on, using DDC, the standard many monitors accept for brightness commands over the cable. Not every monitor supports it, and some connections (DisplayLink docks, for example) block it. The external monitor brightness post goes through how to check.

If you use an Apple display, macOS already handles its brightness, so the keyboard and Displays slider are your simplest route there.

What should the top and bottom edges do at a desk?

This is where a desk setup differs from a laptop.

By default in Slidr 1.4, the top edge is Switch Apps: slide along it and you step through your open apps in the same order as Command-Tab, then lift to switch. That's very handy when the keyboard isn't in reach. The full story is in switching apps without Command-Tab.

The bottom edge defaults to Keyboard Backlight, which only controls a MacBook's built-in keyboard. If your MacBook is closed on a stand, or you're on a Mac mini, that isn't much use. Switch the bottom edge to Media instead:

• double-tap the bottom edge to play or pause

• slide right for the next track, left for the previous one

On Macs without keyboard illumination, Slidr picks Media for the bottom edge automatically.

If you watch a lot of video at the desk, set the top edge to Scrub Video instead of Switch Apps. Each tick moves 5 seconds with a timestamp overlay, and it seeks when you lift. It works with players that report to macOS Now Playing, such as Music, Spotify, IINA, and video in Safari and Chrome tabs.

Will it get in the way of normal trackpad use?

Every edge slide uses a single finger, so the multi-finger gestures you already use (scrolling, Mission Control, switching spaces, Notification Centre from the right edge) keep working. On a large trackpad, set Edge Width to Narrow if you keep catching the edge while moving the pointer. Palm rejection is built in, so a resting hand doesn't start a slide, and you can pause Slidr in any app that needs the whole trackpad.

On Force Touch Magic Trackpads, haptic ticks let you feel each step. Apple's Force Touch article notes that rechargeable Magic Trackpad models have Force Touch. You can set haptics to Off, Light, Medium or Strong.

What if my monitor doesn't support DDC?

If your monitor responds to DDC, this setup removes the most annoying part of using an external display: crouching to find the monitor's buttons. Slidr has a 3-day free trial with no payment or account, then it's $4.99 once for up to 3 Macs. If your monitor doesn't support DDC, volume and the other edges still work, and you'll know within a few minutes of the trial.