Secrets of Mac trackpad, from iBook to MacBook Air

Editor’s Note: This story is excerpted from Computerworld. For more Mac coverage, visit Computerworld’s Macintosh Knowledge Center.

The laptop trackpad has come a long way since Apple Inc. pioneered it 14 years ago on the PowerBook 500 series as a replacement for the trackball found on earlier models.

While almost anyone who has ever used a laptop knows the basics of using a trackpad as a pointing device (simply drag your finger over its surface to move the cursor on-screen), not everyone knows about all the features that Apple has added to its trackpads over the years.

Depending on the Mac notebook model, there are up to 10 specialized trackpad functions you can use to make navigating the screen, Mac OS X and various applications faster and easier.

The trackpad options discussed in this article are not enabled by default; you can enable them all in System Preferences using the Trackpad tab of the Keyboard & Mouse pane. The exact look of this pane will vary depending on the Mac model and on the version of Mac OS X installed, but most will look something like the figure shown below. Some options require hardware support and thus are available only on specific models.

In this article, I’ll look at each of the trackpad functions, beginning with the most basic and widely supported and moving on to the latest and greatest options available only on new MacBook Air and MacBook Pro models.

Basic one-finger features

The most basic set of options for Mac trackpads are performed with single-finger motions. These options have been around since long before Mac OS X; they’re supported on every Mac notebook since the original iBook, as well as a handful of earlier PowerBooks.

Although widely supported, many novice users (and some experienced Mac users) aren’t aware of some of these features or their usefulness. Single-finger options include tap to click, tap and drag, and drag lock. They’re pretty basic, but they save time and make using the trackpad more intuitive.

Tap to click: Probably the most underrated of all trackpad options is tap to click. When it’s enabled, a single tap on the trackpad acts as a mouse click.

This allows you to easily make selections without changing your hand position. Simply move the cursor over the item you want to select or button that you want to click, and tap your finger.

Dragging: With dragging enabled, you can tap on an item (such as an icon, a window’s title bar, or text) to select it and move your finger without lifting it off the trackpad. The selected item drags around the screen the same as if you were holding a mouse button down. Lift your finger off the trackpad, and the item is released as if you had taken your finger off the mouse button.

Drag lock: It isn’t uncommon to run up against the edge of the trackpad when you’re dragging an item across the screen, which can lead you to drop the item someplace unintended. That’s where drag lock comes in.

The effective use is the same as dragging, except that the selected item isn’t released when you lift your finger. If you reach the edge of the trackpad, just reposition your finger and keep dragging. A second tap of the trackpad (or a click of the trackpad button) releases the item.

Tip: A secret feature for users of pre-2005 trackpads

Early Mac trackpads could not distinguish input from two fingers, but this deficiency harbored a hidden advantage: If you place a finger at one edge of these trackpads, then place another finger at the opposite edge and remove the first finger, the cursor’s position shifts almost entirely across the screen, eliminating the need to repeatedly drag a finger across the trackpad surface.

This “feature” remained until Apple introduced trackpads capable of understanding two-finger input in 2005.

Two-finger functions

While the single-finger trackpad features have been around for many years, two-finger clicking and scrolling options were introduced on the PowerBook G4 models in 2005 and were added to iBook G4 models later that year. They have become standard features on MacBooks and MacBook Pros.

When enabled, these features prove invaluable, particularly for users accustomed to using multibutton mice and mice with scroll wheels. Since they are hardware-based, they won’t work on pre-2005 notebooks, although you can add similar functionality to some older models using the handy iScroll2 utility.

Two-finger scrolling: When this option is enabled, placing two fingers on the trackpad and moving them across the trackpad simultaneously simulates a scroll wheel on a mouse: The active window scrolls as if you were using the scroll bar. (In OS X Leopard, you can even scroll through background windows.)

Like the scroll ball on Apple’s Mighty Mouse, the trackpad’s two-finger scrolling is omnidirectional, so you can scroll up and down as well as left to right.

Once you’re gotten used to two-fingered scrolling, you’ll find that it becomes an integral part of Web browsing or skimming through documents, because you don’t need to take your focus off of what you’re looking at to keep reading.

Secondary click: No less useful is the two-fingered secondary click option. Windows users are used to right-click with a two-button mouse or trackpad to see options in a contextual menu. Despite Apple’s penchant for one-button mice and trackpads, Mac OS X and many applications make use of similar contextual menus.

Users of pre-2005 Mac notebooks had to press the control key when clicking to simulate right clicking, but in newer models with two-finger secondary clicking enabled, simply tapping the trackpad with two fingers at one time produces the same effect.

Note: This feature was introduced with the MacBook Pro and MacBook in 2006, but PowerBook G4 and iBook models released in 2005 (those that support two-fingered scrolling) will offer it if they are running Mac OS X Leopard.

Multitouch gestures

The most notable and recently added trackpad functions, known as multitouch gestures, were introduced earlier this year on the MacBook Air and later appeared in the most recent MacBook Pro models. (Since the multitouch features rely on new hardware, they’re not available in older models.)

Multitouch gestures take many of the touch-screen gestures used in the iPhone and iPod Touch and bring them to the trackpad. They work particularly well on the MacBook Air, which has a larger than normal trackpad surface area.

Multitouch gestures let you:

  • Pinch your fingers together and push them apart to zoom in and out of a document
  • Rotate images by placing one finger (typically the thumb) on the trackpad and then rotating the a second finger around it
  • Swipe the trackpad with three fingers to navigate through a series of items, such as pages in a browser history or photos in an iPhoto album

On Macs that support multitouch gestures, the Trackpad options in System Preferences provide video tutorials of how to use the features.

Although multitouch gestures have an extreme cool factor, they can also be helpful in navigating and zooming, particularly when working with Web pages in Safari, images in iPhoto or Aperture, or images and PDF files in Preview.

See Computerworld’s Ken Mingis demonstrating the new multitouch gestures in this short video.

Note that unlike the trackpad features introduced on earlier Mac notebooks, multitouch gestures require application support. This means that not all gestures are supported in all applications, or even in some parts of the Finder.

This is understandable because these gestures are creating specific effects that will work differently depending on the type of application or media they’re being used with. Earlier trackpad options, by contrast, simply simulate standard input-device functionality that works the same regardless of the application.

Some extra trackpad tidbits

In addition to the basic single-finger, two-finger, and multitouch gesture options for trackpads, there are a few noteworthy additional options. In some cases, these are model-specific, and in others they are general options.

Screen zooming: This option, which can also be used with a mouse, lets you hold down a modifier key (by default the control key) while swiping you hand up or down on the trackpad to zoom the entire display in or out. This can be a handy way of getting a closer look at images or hard to read text without resetting your display’s resolution.

In addition to changing the modifier key, you can specify when the feature is available and whether to smooth the edges of images and text while zooming.

Ignore accidental trackpad input: It isn’t uncommon for notebooks users to accidentally brush the trackpad with a palm, wrist or forearm while typing. Typically, this places the cursor somewhere else on-screen (such as an entirely different application) or selects text in the wrong part of the document.

This option tells the Mac to ignore any input from the trackpad at the same time that keys are being pressed (other than special modifier keys), thus ensuring that the cursor stays in place when you’re typing.

Ignore trackpad when mouse is present: This does exactly what it implies: ignores any trackpad input if a mouse or other pointing device is attached to a Mac notebook. This prevents accidental input if you brush the trackpad with your hand or arm.

Finally, don’t forget to adjust the speeds required for the cursor tracking, double-clicking and, on machines that support it, two-fingered scrolling.

Put your trackpad on steroids

If Apple’s array of trackpad features isn’t enough for you, you may want to check out SideTrack (shareware, $15). An alternate trackpad driver, SideTrack enables a whole new range of special gestures and other tricks.

With SideTrack, you can create horizontal and vertical “scroll zones” along the edges of the trackpad (as some Windows notebooks offer), map the trackpad button as a left- or right-click, map the action taken when you tap on the trackpad to varying types of clicking and dragging features, and even map the taps in the corners of trackpad to specific features (much as you can with a multibutton mouse).

SideTrack works on a much wider range of older Mac notebooks than Apple’s built-in features do. Ironically, though, SideTrack doesn’t currently support the newest MacBook Pro and MacBook Air models with multitouch trackpads.

[Ryan Faas is a frequent Computerworld contributor specializing in Mac and multiplatform network issues. You can find more information about him]

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