github.com/acrespo/mobile@v0.0.0-20190107162257-dc0771356504/event/touch/touch.go (about)

     1  // Copyright 2015 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // Package touch defines an event for touch input.
     6  //
     7  // See the golang.org/x/mobile/app package for details on the event model.
     8  package touch // import "golang.org/x/mobile/event/touch"
     9  
    10  // The best source on android input events is the NDK: include/android/input.h
    11  //
    12  // iOS event handling guide:
    13  // https://developer.apple.com/library/ios/documentation/EventHandling/Conceptual/EventHandlingiPhoneOS
    14  
    15  import (
    16  	"fmt"
    17  )
    18  
    19  // Event is a touch event.
    20  type Event struct {
    21  	// X and Y are the touch location, in pixels.
    22  	X, Y float32
    23  
    24  	// Sequence is the sequence number. The same number is shared by all events
    25  	// in a sequence. A sequence begins with a single TypeBegin, is followed by
    26  	// zero or more TypeMoves, and ends with a single TypeEnd. A Sequence
    27  	// distinguishes concurrent sequences but its value is subsequently reused.
    28  	Sequence Sequence
    29  
    30  	// Type is the touch type.
    31  	Type Type
    32  }
    33  
    34  // Sequence identifies a sequence of touch events.
    35  type Sequence int64
    36  
    37  // Type describes the type of a touch event.
    38  type Type byte
    39  
    40  const (
    41  	// TypeBegin is a user first touching the device.
    42  	//
    43  	// On Android, this is a AMOTION_EVENT_ACTION_DOWN.
    44  	// On iOS, this is a call to touchesBegan.
    45  	TypeBegin Type = iota
    46  
    47  	// TypeMove is a user dragging across the device.
    48  	//
    49  	// A TypeMove is delivered between a TypeBegin and TypeEnd.
    50  	//
    51  	// On Android, this is a AMOTION_EVENT_ACTION_MOVE.
    52  	// On iOS, this is a call to touchesMoved.
    53  	TypeMove
    54  
    55  	// TypeEnd is a user no longer touching the device.
    56  	//
    57  	// On Android, this is a AMOTION_EVENT_ACTION_UP.
    58  	// On iOS, this is a call to touchesEnded.
    59  	TypeEnd
    60  )
    61  
    62  func (t Type) String() string {
    63  	switch t {
    64  	case TypeBegin:
    65  		return "begin"
    66  	case TypeMove:
    67  		return "move"
    68  	case TypeEnd:
    69  		return "end"
    70  	}
    71  	return fmt.Sprintf("touch.Type(%d)", t)
    72  }