@@ 1,5 1,12 @@ // SPDX-License-Identifier: Unlicense OR MIT
  
+ /*
+ Package gesture implements common pointer gestures.
+ 
+ Gestures accept low level pointer Events from an input
+ Queue and detect higher level actions such as clicks
+ and scrolling.
+ */
  package gesture
  
  import (


@@ 13,19 20,29 @@ "gioui.org/ui/pointer"
  )
  
+ // Click detects click gestures in the form
+ // of ClickEvents.
+ type Click struct {
+ 	// State tracks the current state
+ 	State ClickState
+ }
+ 
+ type ClickState uint8
+ 
+ // ClickEvent represent a click action, either a
+ // TypePress for the beginning of a click or a
+ // TypeClick for a completed click.
  type ClickEvent struct {
  	Type     ClickType
  	Position f32.Point
  	Source   pointer.Source
  }
  
- type ClickState uint8
  type ClickType uint8
  
- type Click struct {
- 	State ClickState
- }
- 
+ // Scroll detects scroll gestures and reduce them to
+ // scroll distances. Scroll recognizes mouse wheel
+ // movements as well as drag and fling touch gestures.
  type Scroll struct {
  	dragging  bool
  	axis      Axis


@@ 61,7 78,11 @@ )
  
  const (
+ 	// TypePress is reported for the first pointer
+ 	// press.
  	TypePress ClickType = iota
+ 	// TypeClick is reporoted when a click action
+ 	// is complete.
  	TypeClick
  )
  


@@ 76,11 97,13 @@ thresholdVelocity = 1
  )
  
+ // Add the handler to the operation list to receive click events.
  func (c *Click) Add(ops *ui.Ops) {
  	op := pointer.HandlerOp{Key: c}
  	op.Add(ops)
  }
  
+ // Events reports all click events for the available events.
  func (c *Click) Events(q input.Queue) []ClickEvent {
  	var events []ClickEvent
  	for evt, ok := q.Next(c); ok; evt, ok = q.Next(c) {


@@ 114,6 137,7 @@ return events
  }
  
+ // Add the handler to the operation list to receive scroll events.
  func (s *Scroll) Add(ops *ui.Ops) {
  	oph := pointer.HandlerOp{Key: s, Grab: s.grab}
  	oph.Add(ops)


@@ 122,14 146,18 @@ }
  }
  
+ // Stop any remaining fling movement.
  func (s *Scroll) Stop() {
  	s.flinger = flinger{}
  }
  
+ // Dragging reports whether the user is dragging the Scroll.
  func (s *Scroll) Dragging() bool {
  	return s.dragging
  }
  
+ // Scroll detects the scrolling distance from the available events and
+ // ongoing fling gestures.
  func (s *Scroll) Scroll(cfg ui.Config, q input.Queue, axis Axis) int {
  	if s.axis != axis {
  		s.axis = axis


@@ 215,6 243,7 @@ }
  }
  
+ // Active reports whether a fling gesture is in progress.
  func (s *Scroll) Active() bool {
  	return s.flinger.Active()
  }