@@ 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()
}