Module screen_reader_touch 

Explore by touch: what a finger means while the built-in screen reader is on, as TalkBack and VoiceOver read it.

• A finger resting or dragging on the screen explores: the item under it is spoken and the reading cursor moves there, and nothing is pressed. Lifting the finger leaves the cursor where it is.
• A quick tap explores the item under it too, once it is clear no second tap follows.
• A double tap anywhere activates the item the cursor is on.
• A quick one-finger swipe right or left moves to the next or previous item.

A second finger ends the gesture: nothing more is read from the contacts until every finger has lifted.

One recognizer for every host. It is pure: the host passes each contact in the window’s logical pixels with its time, arms a timer for TouchExplorer::deadline and calls TouchExplorer::poll when it fires. A finger that has not yet moved past TAP_SLOP is not read until EXPLORE_DELAY has passed, so the start of a swipe or the first tap of a double tap never moves the cursor.

Structs

TouchExplorer

Reads one-finger touches as the screen reader’s gestures.

Enums

ExploreGesture

What a finger asked the screen reader for.

Constants

DOUBLE_TAP_SLOP

How far, in logical pixels, the second tap of a double tap may land from the first.

DOUBLE_TAP_TIMEOUT

The longest wait between a tap’s lift and the second tap’s touch.

EXPLORE_DELAY

How long a resting finger waits before it explores, so a tap or the start of a swipe reads nothing.

SWIPE_MAX

The longest a swipe takes from touch to lift; a slower movement explores.

SWIPE_MIN

The shortest horizontal distance, in logical pixels, a swipe covers.

TAP_SLOP

How far, in logical pixels, a finger travels before it is moving rather than resting.