Move analyzer to parent, only use one object for analysis

Author: DreamingInBinary

BFRImageViewController/BFRImageContainerViewController.h

@@ -7,6 +7,7 @@
 //
 
 #import <UIKit/UIKit.h>
+#import "BFRImageViewer-Swift.h"
 
 typedef NS_ENUM(NSUInteger, BFRImageAssetType) {
     BFRImageAssetTypeImage,
@@ -42,6 +43,11 @@ typedef NS_ENUM(NSUInteger, BFRImageAssetType) {
 
 /*! Assigning YES to this property will disable autoplay for live photos when it used with 3DTouch peek feature */
 @property (nonatomic, getter=shouldDisableAutoplayForLivePhoto) BOOL disableAutoplayForLivePhoto;
+
+/*! The max scale the image can be maginified at. */
 @property (nonatomic, assign) CGFloat imageMaxScale;
 
+/*! Kicks off image analysis if the image has been properly loaded. */
+- (void)analyzeImageIfPossible:(LiveTextManager * _Nonnull)manager API_AVAILABLE(ios(16));
+
 @end

BFRImageViewController/BFRImageContainerViewController.m

@@ -10,7 +10,6 @@
 #import "BFRBackLoadedImageSource.h"
 #import "BFRImageViewerDownloadProgressView.h"
 #import "BFRImageViewerConstants.h"
-#import "BFRImageViewer-Swift.h"
 #import <Photos/Photos.h>
 #import <PhotosUI/PhotosUI.h>
 #import <PINRemoteImage/PINAnimatedImageView.h>
@@ -50,8 +49,6 @@ @interface BFRImageContainerViewController () <UIScrollViewDelegate, UIGestureRe
 /*! Currently, this only shows if a live photo is displayed to avoid gesture recognizer conflicts with playback and sharing. */
 @property (strong, nonatomic, nullable) UIBarButtonItem *shareBarButtonItem;
 
-@property (strong, nonatomic, nullable) LiveTextManager *liveTextManager API_AVAILABLE(ios(16));
-
 @end
 
 @implementation BFRImageContainerViewController
@@ -153,6 +150,15 @@ - (void)dealloc {
     [[NSNotificationCenter defaultCenter] removeObserver:self];
 }
 
+#pragma mark - Public Methods
+
+- (void)analyzeImageIfPossible:(LiveTextManager *)manager {
+    if (self.imgLoaded && self.imgView) {
+        [manager analyzeImageViewWithView:self.imgView
+                                    image:self.imgLoaded];
+    }
+}
+
 #pragma mark - UI Methods
 
 - (void)createProgressView {
@@ -243,17 +249,6 @@ - (void)createActiveAssetView {
     } else {
         self.imgView = (PINAnimatedImageView *)resizableImageView;
     }
-    
-    // Live Text
-    if (@available(iOS 16.0, *)) {
-        if ([LiveTextManager isLiveTextAvailable] &&
-            (self.assetType == BFRImageAssetTypeImage || self.assetType == BFRImageAssetTypeRemoteImage)) {
-            self.liveTextManager = [LiveTextManager new];
-            [self.liveTextManager analyzeImageViewWithView:self.imgView image:(UIImage *)self.imgLoaded completionHandler:^{
-                            
-            }];
-        }
-    }
 }
 
 - (void)addImageToScrollView {

BFRImageViewController/BFRImageViewController.h

@@ -39,9 +39,12 @@
 /*! Retrieve the index of the currently showing image. */
 @property (nonatomic, assign, readonly) NSInteger currentIndex;
 
-/*! Allows you to enable autoplay for peek&play feature on photo live view. Default to YES */
+/*! Allows you to enable autoplay for peek&play feature on photo live view. Defaults to YES */
 @property (nonatomic, getter=shouldDisableAutoplayForLivePhoto) BOOL disableAutoplayForLivePhoto;
 
+/*! Performs Live Text analysis on the image. Defaults to YES */
+@property (nonatomic, getter=shouldPerformLiveTextAnalysis) BOOL performLiveTextAnalysis;
+
 /*! Allows you to set image max scale */
 @property (nonatomic, assign) CGFloat maxScale;
 

BFRImageViewController/BFRImageViewController.m

@@ -11,6 +11,7 @@
 #import "BFRImageViewerLocalizations.h"
 #import "BFRImageTransitionAnimator.h"
 #import "BFRImageViewerConstants.h"
+#import "BFRImageViewer-Swift.h"
 
 @interface BFRImageViewController () <UIPageViewControllerDataSource, UIScrollViewDelegate>
 
@@ -38,6 +39,9 @@ @interface BFRImageViewController () <UIPageViewControllerDataSource, UIScrollVi
 /*! This creates the parallax scrolling effect by essentially clipping the scrolled images and moving with the touch point in scrollViewDidScroll. */
 @property (strong, nonatomic, nonnull) UIView *parallaxView;
 
+/*! Analyzes images for Live Text detectors. */
+@property (strong, nonatomic, nullable) LiveTextManager *liveTextManager API_AVAILABLE(ios(16));
+
 @end
 
 @implementation BFRImageViewController
@@ -75,7 +79,13 @@ - (void)commonInit {
     self.enableDoneButton = YES;
     self.showDoneButtonOnLeft = YES;
     self.disableAutoplayForLivePhoto = YES;
+    self.performLiveTextAnalysis = YES;
     self.parallaxView = [UIView new];
+    
+    // Add Live Text analysis
+    if (@available(iOS 16.0, *)) {
+        self.liveTextManager = [LiveTextManager new];
+    }
 }
 
 #pragma mark - View Lifecycle
@@ -273,6 +283,32 @@ - (void)scrollViewDidScroll:(UIScrollView *)scrollView {
     [self updateParallaxViewFrame:scrollView];
 }
 
+- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView {
+    // Live Text Interaction
+    if (@available(iOS 16.0, *)) {
+        BFRImageContainerViewController *activeVC = (BFRImageContainerViewController *)self.imageViewControllers[self.currentIndex];
+        
+        BOOL hasAnalyzeableType = (activeVC.assetType == BFRImageAssetTypeImage || activeVC.assetType == BFRImageAssetTypeRemoteImage);
+        
+        if (self.shouldPerformLiveTextAnalysis && hasAnalyzeableType) {
+            [activeVC analyzeImageIfPossible:self.liveTextManager];
+        }
+    }
+}
+
+- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer {
+    // Live Text checks
+    CGPoint windowPoint = [gestureRecognizer locationInView:nil];
+    if (@available(iOS 16, *)) {
+        if (self.shouldPerformLiveTextAnalysis &&
+            [self.liveTextManager hasLiveTextInteractionAtPoint:windowPoint]) {
+            return NO;
+        }
+    }
+    
+    return YES;
+}
+
 - (void)updateParallaxViewFrame:(UIScrollView *)scrollView {
     CGRect bounds = scrollView.bounds;
     CGRect parallaxSeparatorFrame = self.parallaxView.frame;

BFRImageViewController/Live Text/LiveTextManager.swift

@@ -10,23 +10,54 @@ import Foundation
 import VisionKit
 
 @available(iOS 16.0, *)
-@objc @MainActor class LiveTextManager: NSObject {
-    private var interaction = ImageAnalysisInteraction()
+@objc @MainActor class LiveTextManager: NSObject, ImageAnalysisInteractionDelegate {
+    private let interaction = ImageAnalysisInteraction()
+    private let analyzer = ImageAnalyzer()
+    private let configuration = ImageAnalyzer.Configuration([.text, .machineReadableCode])
+    private var analyzedImage: UIImage? = nil
+    
+    override init() {
+        super.init()
+        interaction.delegate = self
+    }
 
     @objc
     static func isLiveTextAvailable() -> Bool {
         return ImageAnalyzer.isSupported
     }
 
     @objc
-    func analyzeImageView(view: UIView, image: UIImage) async {
-        interaction = ImageAnalysisInteraction()
-        interaction.preferredInteractionTypes = .automatic
-        view.addInteraction(interaction)
+    func analyzeImageView(view: UIView, image: UIImage) {
+        if let inFlightView = interaction.view {
+            inFlightView.removeInteraction(interaction)
+        }
 
-        let configuration = ImageAnalyzer.Configuration([.text, .machineReadableCode])
-        let analyzer = ImageAnalyzer()
-        let analysis = try? await analyzer.analyze(image, configuration: configuration)
-        interaction.analysis = analysis
+        Task {
+            interaction.analysis = nil
+            interaction.preferredInteractionTypes = []
+            analyzedImage = image
+            
+            if let analysis = try? await analyzer.analyze(image, configuration: configuration) {
+                if analyzedImage == image && (analysis.hasResults(for: .text) || analysis.hasResults(for: .machineReadableCode)) {
+                    view.addInteraction(interaction)
+                    interaction.analysis = analysis
+                    interaction.preferredInteractionTypes = .automatic
+                }
+            }
+        }
+    }
+    
+    @objc func hasLiveTextInteractionAt(point: CGPoint) -> Bool {
+        return interaction.hasInteractiveItem(at: point) || interaction.hasActiveTextSelection
+    }
+    
+    @objc func updateContentRect() {
+        interaction.setContentsRectNeedsUpdate()
+    }
+    
+    // MARK: Delegate
+    
+    nonisolated func interaction(_ interaction: ImageAnalysisInteraction, shouldBeginAt point: CGPoint, for interactionType: ImageAnalysisInteraction.InteractionTypes) -> Bool {
+        return hasLiveTextInteractionAt(point: point)
     }
 }