Pointer gestures have single-pointer alternatives

Pinch-to-zoom, two-finger swipe, or multi-touch gesture controls exclude users with one functional hand, tremor, or other conditions that prevent multi-pointer input. WCAG 2.2 SC 2.5.1 (Pointer Gestures) is a Level A requirement: all functionality that uses multipoint or path-based gestures must also be operable with a single pointer using no path constraint. An image gallery that requires pinch-to-zoom with no zoom buttons cannot be used with one finger.

For every multi-pointer gesture, provide single-pointer button controls that perform the same action.

// Image viewer with single-pointer zoom buttons alongside pinch-to-zoom
export function ImageViewer({ src }: { src: string }) {
  const [scale, setScale] = useState(1)

  return (
    <div>
      <div className="flex gap-2 mb-2">
        <button onClick={() => setScale(s => Math.max(1, s - 0.25))} aria-label="Zoom out">
          −
        </button>
        <button onClick={() => setScale(s => Math.min(4, s + 0.25))} aria-label="Zoom in">
          +
        </button>
        <button onClick={() => setScale(1)} aria-label="Reset zoom">
          Reset
        </button>
      </div>
      <img
        src={src}
        style={{ transform: `scale(${scale})`, transformOrigin: 'top left' }}
        alt=""
      />
    </div>
  )
}

For swipeable carousels, add previous/next buttons. For map panning, add directional controls. The pointer gesture can remain — it just cannot be the only way.

• ID: accessibility-wcag.understandable.pointer-alternative

• Severity: low

• What to look for: Enumerate every relevant item. Check for multi-pointer gestures like pinch-to-zoom, two-finger tap, or swipe with multiple fingers. Verify that single-pointer alternatives exist (e.g., buttons for zoom).

• Pass criteria: At least 1 of the following conditions is met. All multi-pointer gestures have single-pointer alternatives. Path-dependent gestures (draw, swipe in specific pattern) have simpler alternatives.

• Fail criteria: Functionality requires complex multi-pointer gestures with no alternative.

• Skip (N/A) when: The project has no pointer-based gestures.

• Detail on fail: Example: "Image gallery requires pinch-to-zoom with no zoom buttons. Slider requires swipe gesture with no keyboard or button controls"

• Remediation: Provide alternative controls:

  // Instead of pinch-to-zoom only, add buttons
  <button onClick={() => setZoom(zoom + 1)}>Zoom In</button>
  <button onClick={() => setZoom(zoom - 1)}>Zoom Out</button>
  <Image style={{ transform: `scale(${zoom})` }} />