Here is some of my code
//
// StrokeGestureRecognizer.swift
// Animate3D
//
// Created by Georg Graf on 07.07.23.
//
import UIKit
class StrokeGestureRecognizer: UIGestureRecognizer {
// MARK: - Configuration
var collectsCoalescedTouches = true
var usesPredictedSamples = true
var coordinateSpaceView: UIView?
var ensuredReferenceView: UIView {
if let view = coordinateSpaceView {
return view
} else {
return view!
}
}
/// A Boolean value that determines whether the gesture recognizer tracks Apple Pencil or finger touches.
/// - Tag: isForPencil
var isForPencil: Bool = true {
didSet {
if isForPencil {
allowedTouchTypes = [UITouch.TouchType.pencil.rawValue as NSNumber]
} else {
allowedTouchTypes = [UITouch.TouchType.direct.rawValue as NSNumber]
}
}
}
// MARK: - State
var trackedTouch: UITouch?
var collectForce = true
var stroke = Stroke()
// MARK: - Line data collection
/// Appends touch data to the stroke sample.
/// - Tag: appendTouches
func append(touches: Set<UITouch>, event: UIEvent?) -> Bool {
// Check that we have a touch to append, and that touches
// doesn't contain it.
guard let touchToAppend = trackedTouch, touches.contains(touchToAppend) == true
else { return false }
if collectsCoalescedTouches {
if let event = event {
let coalescedTouches = event.coalescedTouches(for: touchToAppend)!
let lastIndex = coalescedTouches.count - 1
for index in 0..<lastIndex {
let location = coalescedTouches[index].preciseLocation(in: ensuredReferenceView)
stroke.saveStrokeSample(coordinates: location, force: getForceRatio(touch: coalescedTouches[index]))
}
let location = coalescedTouches[lastIndex].preciseLocation(in: ensuredReferenceView)
stroke.saveStrokeSample(coordinates: location, force: getForceRatio(touch: coalescedTouches[lastIndex]))
}
} else {
let location = touchToAppend.preciseLocation(in: ensuredReferenceView)
stroke.saveStrokeSample(coordinates: location, force: getForceRatio(touch: touchToAppend))
}
if usesPredictedSamples && stroke.state == .active {
if let predictedTouches = event?.predictedTouches(for: touchToAppend) {
for touch in predictedTouches {
// do nothing for now
}
}
}
return true
}
private func getForceRatio(touch: UITouch) -> CGFloat {
print("touch.force: \(touch.force), maxPossible: \(touch.maximumPossibleForce)")
return touch.force / touch.maximumPossibleForce
}
// MARK: - Touch handling methods
/// A set of functions that track touches.
/// - Tag: HandleTouches
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
stroke = Stroke()
if trackedTouch == nil {
trackedTouch = touches.first
collectForce = trackedTouch!.type == .pencil
// || view?.traitCollection.forceTouchCapability == .available
print("collectForce: \(collectForce)")
}
if append(touches: touches, event: event) {
if isForPencil {
state = .began
}
}
}
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
if append(touches: touches, event: event) {
if state == .began {
state = .changed
}
}
}
override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
print("touchesEnded")
if append(touches: touches, event: event) {
stroke.state = .done
state = .ended
}
}
override func touchesCancelled(_ touches: Set<UITouch>, with event: UIEvent?) {
print("touchesCancelled")
if append(touches: touches, event: event) {
stroke.state = .cancelled
state = .failed
}
}
override func reset() {
print("reset")
AppState.shared.currentLine = nil
trackedTouch = nil
super.reset()
}
}
justgoscha
Users receive reputation points by contributing quality content to the forums.
Posts include post and replies published on the forums.
Post authors can mark replies as Accepted to indicate successful solutions.
Apple Developer Forums admins can mark replies as Apple Recommended to indicate an approved solution