gestures
Package gestures provides gesture recognition for pointer input, including an arena for resolving competing recognizers and common gesture types like tap and pan.
Variables
DefaultArena is the global gesture arena for the app.
var DefaultArena = NewGestureArena()
DefaultTouchSlop is the movement threshold before a drag wins a gesture.
var DefaultTouchSlop = 12.0
type ArenaMember
ArenaMember participates in the gesture arena.
type ArenaMember interface {
AcceptGesture(pointerID int64)
RejectGesture(pointerID int64)
}
type DragAxis
DragAxis specifies the direction for axis-locked drag recognizers.
type DragAxis int
const (
// DragAxisHorizontal restricts drag detection to horizontal movement.
DragAxisHorizontal DragAxis = iota
// DragAxisVertical restricts drag detection to vertical movement.
DragAxisVertical
)
type DragEndDetails
DragEndDetails describes the end of a drag.
type DragEndDetails struct {
// Position is the final global position of the pointer.
Position graphics.Offset
// Velocity is the velocity of the pointer at release in pixels per second.
Velocity graphics.Offset
// PrimaryVelocity is the axis-specific velocity (0 for Pan, non-zero for axis-locked drags).
PrimaryVelocity float64
}
type DragStartDetails
DragStartDetails describes the start of a drag.
type DragStartDetails struct {
// Position is the global position where the drag started.
Position graphics.Offset
}
type DragUpdateDetails
DragUpdateDetails describes a drag update.
type DragUpdateDetails struct {
// Position is the current global position of the pointer.
Position graphics.Offset
// Delta is the change in position since the last update.
Delta graphics.Offset
// PrimaryDelta is the axis-specific delta (0 for Pan, non-zero for axis-locked drags).
PrimaryDelta float64
}
type GestureArena
GestureArena resolves competing gesture recognizers per pointer.
type GestureArena struct {
// contains filtered or unexported fields
}
func NewGestureArena
func NewGestureArena() *GestureArena
NewGestureArena creates a new arena instance.
func (*GestureArena) Add
func (a *GestureArena) Add(pointerID int64, member ArenaMember)
Add registers a member for a pointer.
func (*GestureArena) Close
func (a *GestureArena) Close(pointerID int64)
Close signals that no more members will be added for this pointer.
func (*GestureArena) Hold
func (a *GestureArena) Hold(pointerID int64, member ArenaMember) bool
Hold defers auto-resolution for this member. Returns true if the hold was added successfully. The member must already be in the arena.
func (*GestureArena) Reject
func (a *GestureArena) Reject(pointerID int64, member ArenaMember)
Reject removes a member from the arena.
func (*GestureArena) ReleaseHold
func (a *GestureArena) ReleaseHold(pointerID int64, member ArenaMember)
ReleaseHold removes a hold without resolving or rejecting.
func (*GestureArena) Resolve
func (a *GestureArena) Resolve(pointerID int64, member ArenaMember)
Resolve declares the winner for this pointer.
func (*GestureArena) Sweep
func (a *GestureArena) Sweep(pointerID int64)
Sweep clears the arena entry for a pointer.
type HorizontalDragGestureRecognizer
HorizontalDragGestureRecognizer detects horizontal drag gestures. It wins when |deltaX| > slop before |deltaY| > slop.
type HorizontalDragGestureRecognizer struct {
// contains filtered or unexported fields
}
func NewHorizontalDragGestureRecognizer
func NewHorizontalDragGestureRecognizer(arena *GestureArena) *HorizontalDragGestureRecognizer
NewHorizontalDragGestureRecognizer creates a horizontal drag recognizer.
func (*HorizontalDragGestureRecognizer) AcceptGesture
func (h *HorizontalDragGestureRecognizer) AcceptGesture(pointerID int64)
AcceptGesture is called by the arena when this recognizer wins.
func (*HorizontalDragGestureRecognizer) AddPointer
func (h *HorizontalDragGestureRecognizer) AddPointer(event PointerEvent)
AddPointer registers a pointer down event.
func (*HorizontalDragGestureRecognizer) Dispose
func (h *HorizontalDragGestureRecognizer) Dispose()
Dispose releases resources for the recognizer.
func (*HorizontalDragGestureRecognizer) HandleEvent
func (h *HorizontalDragGestureRecognizer) HandleEvent(event PointerEvent)
HandleEvent processes pointer events for drag detection.
func (*HorizontalDragGestureRecognizer) RejectGesture
func (h *HorizontalDragGestureRecognizer) RejectGesture(pointerID int64)
RejectGesture is called by the arena when this recognizer loses.
type PanGestureRecognizer
PanGestureRecognizer detects pan gestures.
type PanGestureRecognizer struct {
Arena *GestureArena
OnStart func(DragStartDetails)
OnUpdate func(DragUpdateDetails)
OnEnd func(DragEndDetails)
OnCancel func()
// contains filtered or unexported fields
}
func NewPanGestureRecognizer
func NewPanGestureRecognizer(arena *GestureArena) *PanGestureRecognizer
NewPanGestureRecognizer creates a pan recognizer.
func (*PanGestureRecognizer) AcceptGesture
func (p *PanGestureRecognizer) AcceptGesture(pointerID int64)
AcceptGesture is called by the arena when this recognizer wins.
func (*PanGestureRecognizer) AddPointer
func (p *PanGestureRecognizer) AddPointer(event PointerEvent)
AddPointer registers a pointer down event.
func (*PanGestureRecognizer) Dispose
func (p *PanGestureRecognizer) Dispose()
Dispose releases resources for the recognizer.
func (*PanGestureRecognizer) HandleEvent
func (p *PanGestureRecognizer) HandleEvent(event PointerEvent)
HandleEvent processes pointer events for drag detection.
func (*PanGestureRecognizer) RejectGesture
func (p *PanGestureRecognizer) RejectGesture(pointerID int64)
RejectGesture is called by the arena when this recognizer loses.
type PointerEvent
PointerEvent represents a pointer event routed to gesture recognizers.
type PointerEvent struct {
// PointerID uniquely identifies this pointer (finger/mouse).
PointerID int64
// Position is the pointer location in logical pixels.
Position graphics.Offset
// Delta is the change in position since the last event.
Delta graphics.Offset
// Phase indicates the current phase of the pointer interaction.
Phase PointerPhase
}
type PointerPhase
PointerPhase represents the phase of a pointer event.
type PointerPhase int
const (
// PointerPhaseDown indicates the pointer made contact with the surface.
PointerPhaseDown PointerPhase = iota
// PointerPhaseMove indicates the pointer moved while in contact.
PointerPhaseMove
// PointerPhaseUp indicates the pointer lifted from the surface.
PointerPhaseUp
// PointerPhaseCancel indicates the pointer interaction was cancelled.
PointerPhaseCancel
)
func (PointerPhase) String
func (p PointerPhase) String() string
String returns the string representation of the pointer phase.
type TapGestureRecognizer
TapGestureRecognizer detects taps.
type TapGestureRecognizer struct {
Arena *GestureArena
OnTap func()
// contains filtered or unexported fields
}
func NewTapGestureRecognizer
func NewTapGestureRecognizer(arena *GestureArena) *TapGestureRecognizer
NewTapGestureRecognizer creates a tap recognizer.
func (*TapGestureRecognizer) AcceptGesture
func (t *TapGestureRecognizer) AcceptGesture(pointerID int64)
AcceptGesture is called by the arena when this recognizer wins.
func (*TapGestureRecognizer) AddPointer
func (t *TapGestureRecognizer) AddPointer(event PointerEvent)
AddPointer registers a pointer down event.
func (*TapGestureRecognizer) Dispose
func (t *TapGestureRecognizer) Dispose()
Dispose releases resources for the recognizer.
func (*TapGestureRecognizer) HandleEvent
func (t *TapGestureRecognizer) HandleEvent(event PointerEvent)
HandleEvent processes pointer events for tap detection.
func (*TapGestureRecognizer) RejectGesture
func (t *TapGestureRecognizer) RejectGesture(pointerID int64)
RejectGesture is called by the arena when this recognizer loses.
type VerticalDragGestureRecognizer
VerticalDragGestureRecognizer detects vertical drag gestures. It wins when |deltaY| > slop before |deltaX| > slop.
type VerticalDragGestureRecognizer struct {
// contains filtered or unexported fields
}
func NewVerticalDragGestureRecognizer
func NewVerticalDragGestureRecognizer(arena *GestureArena) *VerticalDragGestureRecognizer
NewVerticalDragGestureRecognizer creates a vertical drag recognizer.
func (*VerticalDragGestureRecognizer) AcceptGesture
func (v *VerticalDragGestureRecognizer) AcceptGesture(pointerID int64)
AcceptGesture is called by the arena when this recognizer wins.
func (*VerticalDragGestureRecognizer) AddPointer
func (v *VerticalDragGestureRecognizer) AddPointer(event PointerEvent)
AddPointer registers a pointer down event.
func (*VerticalDragGestureRecognizer) Dispose
func (v *VerticalDragGestureRecognizer) Dispose()
Dispose releases resources for the recognizer.
func (*VerticalDragGestureRecognizer) HandleEvent
func (v *VerticalDragGestureRecognizer) HandleEvent(event PointerEvent)
HandleEvent processes pointer events for drag detection.
func (*VerticalDragGestureRecognizer) RejectGesture
func (v *VerticalDragGestureRecognizer) RejectGesture(pointerID int64)
RejectGesture is called by the arena when this recognizer loses.
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