~eliasnaur/gio

5d28f9e690946f0eb870177c077039d5a72b1a0d — Elias Naur 1 year, 10 months ago 9cc6757
ui/gesture: add documentation

Signed-off-by: Elias Naur <mail@eliasnaur.com>
1 files changed, 34 insertions(+), 5 deletions(-)

R ui/gesture/{gestures.go => gesture.go}
R ui/gesture/gestures.go => ui/gesture/gesture.go +34 -5
@@ 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 @@ import (
	"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 (
)

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 @@ const (
	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 @@ func (c *Click) Events(q input.Queue) []ClickEvent {
	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 @@ func (s *Scroll) Add(ops *ui.Ops) {
	}
}

// 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 @@ func (s *Scroll) val(p f32.Point) float32 {
	}
}

// Active reports whether a fling gesture is in progress.
func (s *Scroll) Active() bool {
	return s.flinger.Active()
}