All functionality that uses multipoint or path-based gestures for operation can be operated with a single pointer without a path-based gesture, unless a multipoint or path-based gesture is essential.
This requirement applies to web content that interprets pointer actions (i.e. this does not apply to actions that are required to operate the user agent or assistive technology).
2.5.1 Pointer Gestures fundamentally intends to ensure that wide variety of pointing devices, assistive technologies and user abilities can use functionalities derived by the author defined pointing gestures.
Some pointing devices include specialized or adapted input device such as a head pointer, eye-gaze system, or speech-controlled mouse emulator. Due to the inability of performing multi-finger or complex path-based gestures, users may lose functionality that are available only with these gestures.
What is a path-based gesture?
A path-based gesture involves an interaction where not just the endpoints matter. If going through an intermediate point (usually near the start of the gesture) also affects its meaning then it is a path-based gesture. The user engages a pointer (starting point), carries out a movement that goes through at least one intermediate-point before disengaging the pointer (end point). The intermediate point defines the gesture as requiring a specific path, even if the complete path is not defined.
Examples of path-based and multipoint gestures
- Two-finger pinch for zoom
- Two-finger double tap – magic tap for IOS (voiceover)
- Two-finger scrub – go back to previous screen (voiceover)
- Swipe down then right – Global context menu (talkback)
Note: The above gestures are just examples of multipoint or path-based gestures. These are operating system or assistive technology specific gestures that do not fall under this success criterion. 2.5.1 Pointer Gestures is specific to the gestures defined by the content authors.
This success criterion does not restrict content authors from providing path-based or multipoint gestures, the requirement is only to provide an alternate way to accomplish the same task or functionality
For example, instead of just the scrub gesture to move to previous screen, a back button helps to do the same task. A keyboard command or keyboard equivalent is also required to support this success criterion if the functionalities of the content require complex gestures. See success criterion 2.1.1 keyboard
Benefits of 2.5.1 Pointer Gestures
- People due to physical challenges , if depend on pointer devices cannot use multipoint gestures.
- People who have cognitive challenges or learning difficulties may not be able to remember the author defined gestures and rely on alternate functionalities.
Exceptions for 2.5.1 Pointer Gestures
An exception is made for functionality that is inherently and necessarily based on complex paths or multipoint gestures. For example, entering your signature may be inherently path-based (although acknowledging something or confirming your identity need not be).
Gestures that involve dragging in any direction are not in scope for this SC because only the start and end points matter in a dragging operation. However, such gestures do require fine motor control. Authors are encouraged to provide non-dragging methods, for instance, a drag and drop operation could also be achieved by selecting an item (with a tap or keyboard interaction) and then selecting its destination as a second step.