Title: Theory / Important / CS / Programming / Objective-C / Library / UIKit / Touch / General
On every note of this deck, unless a note says otherwise:
Page: https://developer.apple.com/documentation/uikit/uitouch?language=objc
Page: https://developer.apple.com/documentation/uikit/uitouch?language=objc

Variable: touch.view
Meaning: The view to which touches are being delivered, or nil
Language: Objective-C
Variables: UITouch touch

Variable: touch.window
Meaning: The window in which the touch initially occurred.
Language: Objective-C
Variables: UITouch touch

Variable: touch.majorRadius
Meaning: The radius (in points) of the touch.
Language: Objective-C
Variables: UITouch touch

Variable: touch.majorRadiusTolerance
Meaning: The tolerance in points of the touch's radious
Language: Objective-C
Variables: UITouch touch

Variable: touch.tapCount
Meaning: The number of times the finger was tapped for this given touch.
Language: Objective-C
Variables: UITouch touch

Variable: touch.timestamp
Meaning: The time when the touch occurred or when it was last mutated.
Language: Objective-C
Variables: UITouch touch

Variable: touch.type
Meaning: The type of the touch.
Language: Objective-C
Typ: UITouchType
Variables: UITouch touch

Variable: touch.phase
Meaning: The phase of the touch (becang, moved, ended, cancelled)
Language: Objective-C
Typ: UITouchPhase
Variables: UITouch touch

Variable: touch.force
Meaning: The force of the touch, with 1.0 average force.
Language: Objective-C
Variables: UITouch touch
Assuming: 3D touch or apple pencil

Variable: touch.maximumPossibleForce
Meaning: The maximum possible force for a touch.
Language: Objective-C
Variables: UITouch touch

Variable: touch.altitudeAngle
Meaning: The altitude (in radians) of the stylus.
Language: Objective-C
Variables: UITouch touch

Variable: touch.estimatedProperties
Meaning: A set of touch properties whose values contain only estimates.
Language: Objective-C
Variables: UITouch touch

Variable: touch.estimatedPropertiesExpectingUpdates
Meaning: The set of touch properties for which updated values are expected in the future.
Language: Objective-C
Typ: UITouchProperties
Variables: UITouch touch

Variable: touch.gestureRecognizers
Meaning: The gesture recognizers that are receiving the touch object.
Language: Objective-C
Typ: NSArray<UIGestureRecognizer *>
Variables: UITouch touch

Instruction: [touch
  previousLocationInNodenode
]
Language: Objective-C
Returns: the previous location of the receiver in the coordinate system of the given node.
Variables: UITouch touch

Instruction: [touch
  locationInNode:node
]
Language: Objective-C
Returns: the current location of the receiver in the coordinate system of the given node.
Variables: UITouch touch

Instruction: [touch
  azimuthUnitVectorInView:view
]
Language: Objective-C
Returns: a unit vector that points in the direction of the azimuth of the stylus.
Variables: UITouch touch

Instruction: [touch
  azimuthAngleInView:view
]
Language: Objective-C
Returns: the azimuth angle (in radians) of the stylus.
Variables: UITouch touch

Instruction: [touch
  precisePreviousLocationInView:view
]
Language: Objective-C
Returns: a precise previous location for the touch, when available.
Variables: UITouch touch

Instruction: [touch
  preciseLocationInView:view
]
Language: Objective-C
Returns: a precise location for the touch, when available.
Variables: UITouch touch

Instruction: [touch
  previousLocationInView:view
]
Language: Objective-C
Returns: the previous location of the receiver in the coordinate system of the given view.
Variables: UITouch touch

Instruction: [touch
  locationInView:view
]
Language: Objective-C
Returns: the current location of the receiver in the coordinate system of the given view.
Variables: UITouch touch

Typ: UITouchType
TypMeaning: The type of touch received.
Page: https://developer.apple.com/documentation/uikit/uitouch?language=objc
Language: Objective-C
Variables: UITouch touch
Value: UITouchTypeDirect
A touch resulting from direct contact with the screen.
Value2: UITouchTypeIndirect
A touch that did not result from contact with the screen.
Value3: UITouchTypePencil
A touch from Apple Pencil.
Value4: UITouchTypeIndirectPointer

Typ: UITouchProperties
TypMeaning: A bit mask of touch properties that may get updated.
Page: https://developer.apple.com/documentation/uikit/uitouch?language=objc
Language: Objective-C
Variables: UITouch touch
Value: UITouchPropertyForce
A touch property, representing force, in a bit mask.
Value2: UITouchPropertyAzimuth
A touch property, representing azimuth, in a bit mask.
Value3: UITouchPropertyAltitude
A touch property, representing altitude, in a bit mask.
Value4: UITouchPropertyLocation
A touch property, representing location, in a bit mask.

Typ: UITouchPhase
TypMeaning: The phase of a touch event.
Page: https://developer.apple.com/documentation/uikit/uitouch?language=objc
Language: Objective-C
Variables: UITouch touch
Value: UITouchPhaseBegan
A touch for a given event has pressed down on the screen.
Value2: UITouchPhaseMoved
A touch for a given event has moved over the screen.
Value3: UITouchPhaseStationary
A touch for a given event is pressed down on the screen, but hasn't moved since the previous event.
Value4: UITouchPhaseEnded
A touch for a given event has lifted from the screen.
Value5: UITouchPhaseCancelled
The system canceled tracking for a touch, for example, when the user moves the device against their face.
Value6: UITouchPhaseRegionEntered
A touch for a given event has entered a window on the screen.
Value7: UITouchPhaseRegionMoved
A touch for the given event is within a window on the screen, but has not yet pressed down.
Value8: UITouchPhaseRegionExited
A touch for a given event has left a window on the screen.