Merge pull request #284 from makenotion/master

Allow replacing an image while maintaining the zoom scale and position
JanGorman · Sep 23, 2021 · 9f0e898 · 9f0e898
2 parents bda398a + 5ecca67
commit 9f0e898
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Showing 5 changed files with 171 additions and 47 deletions.
diff --git a/Agrume/Agrume.swift b/Agrume/Agrume.swift
@@ -242,9 +242,18 @@ public final class Agrume: UIViewController {
   /// - Parameters:
   ///   - index: The target index
   ///   - image: The replacement UIImage
-  public func updateImage(at index: Int, with image: UIImage) {
+  ///   - newTitle: The new title, if nil then no change
+  public func updateImage(at index: Int, with image: UIImage, newTitle: NSAttributedString? = nil) {
     assert(images.count > index)
-    let replacement = with(images[index]) { $0.image = image }
+    let replacement = with(images[index]) {
+      $0.url = nil
+      $0.image = image
+      if let newTitle = newTitle {
+        $0.title = newTitle
+      }
+    }
+
+    markAsUpdatingSameCell(at: index)
     images[index] = replacement
     reload()
   }
@@ -253,13 +262,30 @@ public final class Agrume: UIViewController {
   /// - Parameters:
   ///   - index: The target index
   ///   - url: The replacement URL
-  public func updateImage(at index: Int, with url: URL) {
+  ///   - newTitle: The new title, if nil then no change
+  public func updateImage(at index: Int, with url: URL, newTitle: NSAttributedString? = nil) {
     assert(images.count > index)
-    let replacement = with(images[index]) { $0.url = url }
+    let replacement = with(images[index]) {
+      $0.image = nil
+      $0.url = url
+      if let newTitle = newTitle {
+        $0.title = newTitle
+      }
+    }
+
+    markAsUpdatingSameCell(at: index)
     images[index] = replacement
     reload()
   }
 
+  private func markAsUpdatingSameCell(at index: Int) {
+    collectionView.visibleCells.forEach { cell in
+      if let cell = cell as? AgrumeCell, cell.index == index {
+        cell.updatingImageOnSameCell = true
+      }
+    }
+  }
+
   override public func viewDidLoad() {
     super.viewDidLoad()
     addSubviews()
@@ -452,6 +478,7 @@ extension Agrume: UICollectionViewDataSource {
 
     spinner.alpha = 1
     fetchImage(forIndex: indexPath.item) { [weak self] image in
+      cell.index = indexPath.item
       cell.image = image
       self?.spinner.alpha = 0
     }

diff --git a/Agrume/AgrumeCell.swift b/Agrume/AgrumeCell.swift
@@ -52,15 +52,25 @@ final class AgrumeCell: UICollectionViewCell {
   private var imageDragOffsetFromActualTranslation: UIOffset!
   private var imageDragOffsetFromImageCenter: UIOffset!
   private var attachmentBehavior: UIAttachmentBehavior?
+
 
+  // index of the cell in the collection view
+  var index: Int?
+
+  // if set to true, it means we are updating image on the same cell, so we want to reserve the zoom level & position
+  var updatingImageOnSameCell = false
+
   var image: UIImage? {
     didSet {
       if image?.imageData != nil, let image = image {
         imageView.setGifImage(image)
       } else {
         imageView.image = image
       }
-      updateScrollViewAndImageViewForCurrentMetrics()
+      if !updatingImageOnSameCell {
+        updateScrollViewAndImageViewForCurrentMetrics()
+      }
+      updatingImageOnSameCell = false
     }
   }
   weak var delegate: AgrumeCellDelegate?
@@ -88,9 +98,12 @@ final class AgrumeCell: UICollectionViewCell {
 
   override func prepareForReuse() {
     super.prepareForReuse()
-    imageView.image = nil
-    scrollView.zoomScale = 1
-    updateScrollViewAndImageViewForCurrentMetrics()
+
+    if !updatingImageOnSameCell {
+      imageView.image = nil
+      scrollView.zoomScale = 1
+      updateScrollViewAndImageViewForCurrentMetrics()
+    }
   }
 
   private func setupGestureRecognizers() {

diff --git a/Example/Agrume Example.xcodeproj/project.pbxproj b/Example/Agrume Example.xcodeproj/project.pbxproj
@@ -7,6 +7,7 @@
 	objects = {
 
 /* Begin PBXBuildFile section */
+		39CA658926EFFC5700A5A910 /* URLUpdatedToImageViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 39CA658826EFFC5700A5A910 /* URLUpdatedToImageViewController.swift */; };
 		771DA7342179EF1800541206 /* SwiftyGif.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 771DA7332179EF1800541206 /* SwiftyGif.framework */; };
 		9464AFE923C692C7006ADEBD /* OverlayView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 9464AFE823C692C7006ADEBD /* OverlayView.swift */; };
 		948117D723C7A83600AE200D /* MultipleImagesCustomOverlayView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 948117D623C7A83600AE200D /* MultipleImagesCustomOverlayView.swift */; };
@@ -85,6 +86,7 @@
 /* End PBXCopyFilesBuildPhase section */
 
 /* Begin PBXFileReference section */
+		39CA658826EFFC5700A5A910 /* URLUpdatedToImageViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = URLUpdatedToImageViewController.swift; sourceTree = "<group>"; };
 		771DA7332179EF1800541206 /* SwiftyGif.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; path = SwiftyGif.framework; sourceTree = BUILT_PRODUCTS_DIR; };
 		9464AFE823C692C7006ADEBD /* OverlayView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = OverlayView.swift; sourceTree = "<group>"; };
 		948117D623C7A83600AE200D /* MultipleImagesCustomOverlayView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MultipleImagesCustomOverlayView.swift; sourceTree = "<group>"; };
@@ -183,6 +185,7 @@
 				E77809E21D17821400CC60F1 /* SingleImageModalViewController.swift */,
 				F2D9598D1B1A133800073772 /* SingleImageViewController.swift */,
 				F2D959901B1A140200073772 /* SingleURLViewController.swift */,
+				39CA658826EFFC5700A5A910 /* URLUpdatedToImageViewController.swift */,
 				F2A520181B130C7E00924912 /* Supporting Files */,
 			);
 			path = "Agrume Example";
@@ -354,6 +357,7 @@
 			buildActionMask = 2147483647;
 			files = (
 				E77809E31D17821400CC60F1 /* SingleImageModalViewController.swift in Sources */,
+				39CA658926EFFC5700A5A910 /* URLUpdatedToImageViewController.swift in Sources */,
 				F2D959911B1A140200073772 /* SingleURLViewController.swift in Sources */,
 				F2D7BA1F20A47FB500D5EE66 /* AnimatedGifViewController.swift in Sources */,
 				948117D723C7A83600AE200D /* MultipleImagesCustomOverlayView.swift in Sources */,