feat: use DebounceButton for the crop button in the CropToolbar

Mantis.xcodeproj/project.pbxproj

@@ -76,6 +76,7 @@
 		F24DCFEC29AF2A6000D8E8C1 /* CropAuxiliaryIndicatorView+Accessibility.swift in Sources */ = {isa = PBXBuildFile; fileRef = F24DCFEB29AF2A6000D8E8C1 /* CropAuxiliaryIndicatorView+Accessibility.swift */; };
 		F251B36E299B9A52006325B0 /* CropWorkbenchViewTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = F251B36D299B9A52006325B0 /* CropWorkbenchViewTests.swift */; };
 		F28FF64A2C4A492A002F5F06 /* CropAuxiliaryIndicatorConfig.swift in Sources */ = {isa = PBXBuildFile; fileRef = F28FF6492C4A492A002F5F06 /* CropAuxiliaryIndicatorConfig.swift */; };
+		F2AB98582CDC147F003C7CC2 /* DebounceButton.swift in Sources */ = {isa = PBXBuildFile; fileRef = F2AB98572CDC147F003C7CC2 /* DebounceButton.swift */; };
 		F2AD53412A46DB8B00AE9C87 /* ImageAutoAdjustHelper.swift in Sources */ = {isa = PBXBuildFile; fileRef = F2AD53402A46DB8B00AE9C87 /* ImageAutoAdjustHelper.swift */; };
 		F2B4FDA42A3B661B00667F22 /* SlideDial.swift in Sources */ = {isa = PBXBuildFile; fileRef = F2B4FDA32A3B661B00667F22 /* SlideDial.swift */; };
 		F2B4FDA72A3B69B600667F22 /* SlideRulerPositionHelper.swift in Sources */ = {isa = PBXBuildFile; fileRef = F2B4FDA52A3B69B600667F22 /* SlideRulerPositionHelper.swift */; };
@@ -213,6 +214,7 @@
 		F24DCFEB29AF2A6000D8E8C1 /* CropAuxiliaryIndicatorView+Accessibility.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "CropAuxiliaryIndicatorView+Accessibility.swift"; sourceTree = "<group>"; };
 		F251B36D299B9A52006325B0 /* CropWorkbenchViewTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CropWorkbenchViewTests.swift; sourceTree = "<group>"; };
 		F28FF6492C4A492A002F5F06 /* CropAuxiliaryIndicatorConfig.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CropAuxiliaryIndicatorConfig.swift; sourceTree = "<group>"; };
+		F2AB98572CDC147F003C7CC2 /* DebounceButton.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DebounceButton.swift; sourceTree = "<group>"; };
 		F2AD53402A46DB8B00AE9C87 /* ImageAutoAdjustHelper.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ImageAutoAdjustHelper.swift; sourceTree = "<group>"; };
 		F2B4FDA32A3B661B00667F22 /* SlideDial.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SlideDial.swift; sourceTree = "<group>"; };
 		F2B4FDA52A3B69B600667F22 /* SlideRulerPositionHelper.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = SlideRulerPositionHelper.swift; sourceTree = "<group>"; };
@@ -380,6 +382,7 @@
 		OBJ_23 /* CropViewController */ = {
 			isa = PBXGroup;
 			children = (
+				F2AB98572CDC147F003C7CC2 /* DebounceButton.swift */,
 				OBJ_24 /* CropToolbar.swift */,
 				OBJ_25 /* CropViewController.swift */,
 				OBJ_26 /* FixedRatioManager.swift */,
@@ -756,6 +759,7 @@
 				OBJ_75 /* CropView+UIScrollViewDelegate.swift in Sources */,
 				664A7E9F2884606800DF7C79 /* Global.swift in Sources */,
 				F24DCFEC29AF2A6000D8E8C1 /* CropAuxiliaryIndicatorView+Accessibility.swift in Sources */,
+				F2AB98582CDC147F003C7CC2 /* DebounceButton.swift in Sources */,
 				66F4398E2978F6E400728B52 /* UIViewExtensions.swift in Sources */,
 				OBJ_76 /* CropView.swift in Sources */,
 				660D4F57298CDA8C00C4E11A /* TestHelper.swift in Sources */,

Sources/Mantis/CropViewController/CropToolbar.swift

@@ -91,15 +91,21 @@ public final class CropToolbar: UIView, CropToolbarProtocol {
         return button
     }()
 
-    private lazy var cropButton: UIButton = {
+    private lazy var cropButton: DebounceButton = {
         if let icon = iconProvider?.getCropIcon() {
-            let button = createOptionButton(withTitle: nil, andAction: #selector(crop))
+            let button: DebounceButton = createOptionButton(withTitle: nil)
             button.setImage(icon, for: .normal)
+            button.setCropOperation { [weak self] in
+                self?.crop(button)
+            }
             return button
         }
 
         let doneText = LocalizedHelper.getString("Mantis.Done", value: "Done")
-        let button = createOptionButton(withTitle: doneText, andAction: #selector(crop))
+        let button: DebounceButton = createOptionButton(withTitle: doneText)
+        button.setCropOperation { [weak self] in
+            self?.crop(button)
+        }
         button.accessibilityIdentifier = "DoneButton"
         button.accessibilityLabel = doneText
         return button
@@ -282,13 +288,13 @@ extension CropToolbar {
 
 // private functions
 extension CropToolbar {
-    private func createOptionButton(withTitle title: String?, andAction action: Selector) -> UIButton {
+    private func createOptionButton<T: UIButton>(withTitle title: String?, andAction action: Selector? = nil) -> T {
         let buttonColor = config.foregroundColor
         let buttonFont: UIFont = .preferredFont(forTextStyle: .body)
         let fontMetrics = UIFontMetrics(forTextStyle: .body)
         let maxSize = UIFont.systemFontSize * 1.5
 
-        let button = UIButton(type: .system)
+        let button = T(type: .system)
         button.tintColor = config.foregroundColor
         button.titleLabel?.font = fontMetrics.scaledFont(for: buttonFont, maximumPointSize: maxSize)
         button.titleLabel?.adjustsFontForContentSizeCategory = true
@@ -320,7 +326,10 @@ extension CropToolbar {
         button.setContentCompressionResistancePriority(UILayoutPriority(rawValue: compressionPriority), for: .horizontal)
         button.setContentCompressionResistancePriority(UILayoutPriority(rawValue: compressionPriority), for: .vertical)
 
-        button.addTarget(self, action: action, for: .touchUpInside)
+        if let action = action {
+            button.addTarget(self, action: action, for: .touchUpInside)
+        }
+
         button.contentEdgeInsets = UIEdgeInsets(top: 4, left: 10, bottom: 4, right: 10)
 
         button.isAccessibilityElement = true

Sources/Mantis/CropViewController/DebounceButton.swift

@@ -0,0 +1,92 @@
+//
+//  DebounceButton.swift
+//  Mantis
+//
+//  Created by Yingtao Guo on 11/6/24.
+//
+
+import UIKit
+
+/// A custom UIButton subclass that prevents multiple rapid taps and provides debouncing functionality
+class DebounceButton: UIButton {
+    // Default debounce interval in seconds
+    private var debounceInterval: TimeInterval = 0.5
+
+    // Timestamp of the last tap
+    private var lastTapTimestamp: TimeInterval = 0
+
+    // Flag to track if a crop operation is in progress
+    private var isProcessing: Bool = false
+
+    // Closure to store the actual crop operation
+    private var cropOperation: (() -> Void)?
+
+    // MARK: - Initialization
+
+    override init(frame: CGRect) {
+        super.init(frame: frame)
+        setupButton()
+    }
+
+    required init?(coder: NSCoder) {
+        super.init(coder: coder)
+        setupButton()
+    }
+
+    /// Sets up the initial button configuration
+    private func setupButton() {
+        addTarget(self, action: #selector(handleTap), for: .touchUpInside)
+    }
+
+    // MARK: - Public Methods
+
+    /// Sets the minimum time interval between valid taps
+    /// - Parameter interval: The time interval in seconds
+    func setDebounceInterval(_ interval: TimeInterval) {
+        debounceInterval = interval
+    }
+
+    /// Sets the crop operation to be performed when the button is tapped
+    /// - Parameter operation: A closure containing the crop logic
+    func setCropOperation(_ operation: @escaping () -> Void) {
+        cropOperation = operation
+    }
+
+    // MARK: - Private Methods
+
+    /// Handles the button tap event with debouncing logic
+    @objc private func handleTap() {
+        let currentTime = Date().timeIntervalSince1970
+
+        // If a crop operation is already in progress, ignore the tap
+        guard !isProcessing else {
+            return
+        }
+
+        // Check if enough time has passed since the last tap
+        if currentTime - lastTapTimestamp >= debounceInterval {
+            lastTapTimestamp = currentTime
+            isProcessing = true
+
+            // Perform the crop operation
+            performCropOperation()
+        }
+    }
+
+    /// Executes the stored crop operation with proper state management
+    private func performCropOperation() {
+        guard let cropOperation = cropOperation else {
+            isProcessing = false
+            return
+        }
+
+        isEnabled = false        
+        cropOperation()
+
+        DispatchQueue.main.asyncAfter(deadline: .now() + 0.5) { [weak self] in
+            // Re-enable the button and reset processing state
+            self?.isEnabled = true
+            self?.isProcessing = false
+        }
+    }
+}