metatext-app-ios-iphone-ipad/Views/TouchFallthroughTextView.swift

144 lines
4.8 KiB
Swift

// Copyright © 2020 Metabolist. All rights reserved.
import UIKit
final class TouchFallthroughTextView: UITextView {
var shouldFallthrough: Bool = true
private var linkHighlightView: UIView?
override init(frame: CGRect, textContainer: NSTextContainer?) {
super.init(frame: frame, textContainer: textContainer)
clipsToBounds = false
textDragInteraction?.isEnabled = false
isEditable = false
isScrollEnabled = false
delaysContentTouches = false
textContainerInset = .zero
self.textContainer.lineFragmentPadding = 0
linkTextAttributes = [.foregroundColor: tintColor as Any, .underlineColor: UIColor.clear]
}
@available(*, unavailable)
required init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override func point(inside point: CGPoint, with event: UIEvent?) -> Bool {
shouldFallthrough ? urlAndRect(at: point) != nil : super.point(inside: point, with: event)
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
super.touchesBegan(touches, with: event)
guard let touch = touches.first,
let (_, rect) = urlAndRect(at: touch.location(in: self)) else {
return
}
let linkHighlightView = UIView(frame: rect)
self.linkHighlightView = linkHighlightView
linkHighlightView.transform = Self.linkHighlightViewTransform
linkHighlightView.layer.cornerRadius = .defaultCornerRadius
linkHighlightView.backgroundColor = .secondarySystemBackground
insertSubview(linkHighlightView, at: 0)
}
override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
super.touchesEnded(touches, with: event)
removeLinkHighlightView()
}
override func touchesCancelled(_ touches: Set<UITouch>, with event: UIEvent?) {
super.touchesCancelled(touches, with: event)
removeLinkHighlightView()
}
override var selectedTextRange: UITextRange? {
get { shouldFallthrough ? nil : super.selectedTextRange }
set {
if !shouldFallthrough {
super.selectedTextRange = newValue
}
}
}
override var intrinsicContentSize: CGSize {
return text.isEmpty ? .zero : super.intrinsicContentSize
}
func urlAndRect(at point: CGPoint) -> (URL, CGRect)? {
guard
let pos = closestPosition(to: point),
let range = tokenizer.rangeEnclosingPosition(
pos, with: .character,
inDirection: UITextDirection.layout(.left))
else { return nil }
let urlAtPointIndex = offset(from: beginningOfDocument, to: range.start)
guard let url = attributedText.attribute(
.link, at: offset(from: beginningOfDocument, to: range.start),
effectiveRange: nil) as? URL
else { return nil }
let maxLength = attributedText.length
var min = urlAtPointIndex
var max = urlAtPointIndex
attributedText.enumerateAttribute(
.link,
in: NSRange(location: 0, length: urlAtPointIndex),
options: .reverse) { attribute, range, stop in
if let attributeURL = attribute as? URL, attributeURL == url, min > 0 {
min = range.location
} else {
stop.pointee = true
}
}
attributedText.enumerateAttribute(
.link,
in: NSRange(location: urlAtPointIndex, length: maxLength - urlAtPointIndex),
options: []) { attribute, range, stop in
if let attributeURL = attribute as? URL, attributeURL == url, max < maxLength {
max = range.location + range.length
} else {
stop.pointee = true
}
}
var urlRect = CGRect.zero
layoutManager.enumerateEnclosingRects(
forGlyphRange: NSRange(location: min, length: max - min),
withinSelectedGlyphRange: NSRange(location: NSNotFound, length: 0),
in: textContainer) { rect, _ in
if urlRect.origin == .zero {
urlRect.origin = rect.origin
}
urlRect = urlRect.union(rect)
}
return (url, urlRect)
}
}
private extension TouchFallthroughTextView {
static let linkHighlightViewTransform = CGAffineTransform(scaleX: 1.1, y: 1.1)
func removeLinkHighlightView() {
UIView.animate(withDuration: .defaultAnimationDuration) {
self.linkHighlightView?.alpha = 0
} completion: { _ in
self.linkHighlightView?.removeFromSuperview()
self.linkHighlightView = nil
}
}
}