mirror of https://github.com/oxen-io/session-ios
Add stroke drawing to the image editor.
Matthew Chen
6 years ago
parent
b0e0c6e8c2
commit
639dac4e26
@ -0,0 +1,172 @@
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//
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// Copyright (c) 2018 Open Whisper Systems. All rights reserved.
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//
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import UIKit
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class ImageEditorGestureRecognizer: UIGestureRecognizer {
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@objc
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override func canPrevent(_ preventedGestureRecognizer: UIGestureRecognizer) -> Bool {
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return false
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}
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@objc
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override func canBePrevented(by: UIGestureRecognizer) -> Bool {
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return false
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}
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@objc
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override func shouldRequireFailure(of: UIGestureRecognizer) -> Bool {
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return false
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}
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@objc
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override func shouldBeRequiredToFail(by: UIGestureRecognizer) -> Bool {
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return true
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}
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// MARK: - Touch Handling
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@objc
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override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent) {
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super.touchesBegan(touches, with: event)
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if state == .possible,
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touchType(for: touches, with: event) == .valid {
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state = .began
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} else {
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state = .failed
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}
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}
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@objc
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override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent) {
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super.touchesBegan(touches, with: event)
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switch state {
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case .began, .changed:
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switch touchType(for: touches, with: event) {
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case .valid:
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state = .changed
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case .invalid:
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state = .failed
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case .outside:
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state = .ended
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}
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default:
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state = .failed
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}
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}
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@objc
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override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent) {
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super.touchesBegan(touches, with: event)
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switch state {
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case .began, .changed:
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switch touchType(for: touches, with: event) {
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case .valid, .outside:
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state = .changed
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case .invalid:
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state = .failed
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}
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default:
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state = .failed
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}
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}
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@objc
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override func touchesCancelled(_ touches: Set<UITouch>, with event: UIEvent) {
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super.touchesBegan(touches, with: event)
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state = .failed
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}
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public enum TouchType {
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case invalid
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case valid
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case outside
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}
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private func touchType(for touches: Set<UITouch>, with event: UIEvent) -> TouchType {
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guard let view = self.view else {
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owsFailDebug("Missing view")
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return .invalid
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}
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guard let allTouches = event.allTouches else {
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owsFailDebug("Missing allTouches")
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return .invalid
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}
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guard allTouches.count <= 1 else {
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return .invalid
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}
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guard touches.count == 1 else {
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return .invalid
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}
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guard let firstTouch: UITouch = touches.first else {
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return .invalid
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}
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let location = firstTouch.location(in: view)
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let isNewTouch = firstTouch.phase == .began
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if isNewTouch {
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// Reject new touches that are inside a control subview.
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if subviewControl(ofView: view, contains: firstTouch) {
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return .invalid
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}
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}
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// Reject new touches outside this GR's view's bounds.
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guard view.bounds.contains(location) else {
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return isNewTouch ? .invalid : .outside
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}
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// Ignore touches that start near the top or bottom edge of the screen;
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// they may be a system edge swipe gesture.
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let rootView = self.rootView(of: view)
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let rootLocation = firstTouch.location(in: rootView)
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let distanceToTopEdge = max(0, rootLocation.y)
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let distanceToBottomEdge = max(0, rootView.bounds.size.height - rootLocation.y)
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let distanceToNearestEdge = min(distanceToTopEdge, distanceToBottomEdge)
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let kSystemEdgeSwipeTolerance: CGFloat = 50
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if (distanceToNearestEdge < kSystemEdgeSwipeTolerance) {
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return .invalid
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}
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return .valid
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}
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private func subviewControl(ofView superview: UIView, contains touch: UITouch) -> Bool {
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for subview in superview.subviews {
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guard !subview.isHidden, subview.isUserInteractionEnabled else {
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continue
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}
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let location = touch.location(in: subview)
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guard subview.bounds.contains(location) else {
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continue
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}
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if subview as? UIControl != nil {
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return true
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}
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if subviewControl(ofView: subview, contains: touch) {
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return true
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}
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}
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return false
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}
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private func rootView(of view: UIView) -> UIView {
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var responder: UIResponder? = view
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var lastView: UIView = view
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while true {
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guard let currentResponder = responder else {
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return lastView
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}
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if let currentView = currentResponder as? UIView {
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lastView = currentView
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}
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responder = currentResponder.next
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}
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}
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}
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