Zoomify image's initial size correction

Example/iOSTiledViewer.xcodeproj/project.pbxproj

@@ -468,6 +468,7 @@
 				PROVISIONING_PROFILE = "7a270d4e-8a9e-44bc-bfa6-b5b4235feffc";
 				PROVISIONING_PROFILE_SPECIFIER = "IIIF Development";
 				SWIFT_VERSION = 3.0;
+				TARGETED_DEVICE_FAMILY = "1,2";
 			};
 			name = Debug;
 		};
@@ -495,6 +496,7 @@
 				PROVISIONING_PROFILE = "e97c827d-2581-4145-ae4f-2fcd5ed68ce0";
 				PROVISIONING_PROFILE_SPECIFIER = "IIIF Distribution";
 				SWIFT_VERSION = 3.0;
+				TARGETED_DEVICE_FAMILY = "1,2";
 			};
 			name = Release;
 		};

iOSTiledViewer.podspec

@@ -8,7 +8,7 @@
 
 Pod::Spec.new do |s|
   s.name             = 'iOSTiledViewer'
-  s.version          = '0.1.4'
+  s.version          = '0.1.5'
   s.summary          = 'High-resolution images Viewer.'
 
 # This description is used to generate tags and improve search results.

iOSTiledViewer/Classes/IIIF/IIIFImageDescriptorV1.swift

@@ -98,7 +98,7 @@ extension IIIFImageDescriptorV1: ITVImageDescriptor {
     }
 
     // Methods
-    mutating func sizeToFit(size: CGSize, zoomScale: CGFloat) -> CGSize {
+    mutating func sizeToFit(size: CGSize) -> CGSize {
         let imageSize = CGSize(width: width, height: height)
         var aspectFitSize = size
         let mW = aspectFitSize.width / imageSize.width

iOSTiledViewer/Classes/IIIF/IIIFImageDescriptorV2.swift

@@ -143,7 +143,7 @@ extension IIIFImageDescriptorV2: ITVImageDescriptor {
     }
 
 
-    mutating func sizeToFit(size: CGSize, zoomScale: CGFloat) -> CGSize {
+    mutating func sizeToFit(size: CGSize) -> CGSize {
         let imageSize = CGSize(width: width, height: height)
         var aspectFitSize = size
         let mW = aspectFitSize.width / imageSize.width

iOSTiledViewer/Classes/ITVImageDescriptor.swift

@@ -37,5 +37,5 @@ protocol ITVImageDescriptor {
     func getBackgroundUrl() -> URL?
 
     /// Note - Protocol may be implemented by struct, that would need to store size and scale values for further computations. To allow that, function has to be marked as mutating.
-    mutating func sizeToFit(size: CGSize, zoomScale: CGFloat) -> CGSize
+    mutating func sizeToFit(size: CGSize) -> CGSize
 }

iOSTiledViewer/Classes/ITVScrollView.swift

@@ -228,10 +228,10 @@ open class ITVScrollView: UIScrollView {
 
 fileprivate extension ITVScrollView {
 
-    // Resizin tiled view to fit in scroll view
+    // Resizing tiled view to fit in scroll view
     fileprivate func resizeTiledView(image: ITVImageDescriptor) -> ITVImageDescriptor {
         var mutableImage = image
-        let newSize = mutableImage.sizeToFit(size: frame.size, zoomScale: tiledView.contentScaleFactor)
+        let newSize = mutableImage.sizeToFit(size: frame.size)
         tiledView.frame = CGRect(origin: CGPoint.zero, size: newSize)
         scrollViewDidZoom(self)
         return mutableImage
@@ -250,6 +250,7 @@ fileprivate extension ITVScrollView {
         maximumZoomScale = scales.last!
         minimumZoomScale = scales.first!
         zoomScale = minimumZoomScale
+        changeLevel(forScale: minimumZoomScale)
         tiledView.image = image
         licenseView.imageDescriptor = image
 
@@ -274,6 +275,15 @@ fileprivate extension ITVScrollView {
         semaphore.wait()
         return result
     }
+
+    fileprivate func changeLevel(forScale scale: CGFloat) {
+        // redraw image by setting contentScaleFactor on tiledView
+        let level = Int(round(log2(scale)))
+        if level != lastLevel {
+            tiledView.contentScaleFactor = pow(2.0, CGFloat(level))
+            lastLevel = level
+        }
+    }
 }
 
 /// MARK: UIScrollViewDelegate implementation
@@ -292,12 +302,7 @@ extension ITVScrollView: UIScrollViewDelegate {
     }
 
     public func scrollViewDidEndZooming(_ scrollView: UIScrollView, with view: UIView?, atScale scale: CGFloat) {
-        // redraw image by setting contentScaleFactor on tiledView
-        let level = Int(round(log2(scale)))
-        if level != lastLevel {
-            tiledView.contentScaleFactor = pow(2.0, CGFloat(level))
-            lastLevel = level
-        }
+        changeLevel(forScale: scale)
     }
 
     public func viewForZooming(in scrollView: UIScrollView) -> UIView? {

iOSTiledViewer/Classes/ITVTiledView.swift

@@ -57,14 +57,14 @@ class ITVTiledView: UIView {
 
     override func draw(_ rect: CGRect) {
 
-        guard image != nil, let context = UIGraphicsGetCurrentContext() else {
+        guard image != nil, let context = UIGraphicsGetCurrentContext(), !rect.isInfinite, !rect.isNull else {
             return
         }
 
         let viewScale = self.contentScaleFactor
         let viewSize = bounds.width * contentScaleFactor
 
-        let scale = CGFloat(image.width)/viewSize//.width
+        let scale = CGFloat(image.width)/viewSize
 
         let tiledLayer = self.layer as! CATiledLayer
         let tileSize = tiledLayer.tileSize
@@ -73,16 +73,14 @@ class ITVTiledView: UIView {
         let row = Int(rect.midY * viewScale / tileSize.height)
         let level = self.level
 
-        var requestURL: URL!
         /// TODO: make borders setting modifiable to user as well
         let displayTileBorders = false
 
-        let cacheKey = "\(level)/\(column)_\(row)"
+        let cacheKey = "\(level)-\(column)-\(row)"
         if let image = imageCache[cacheKey] {
             image.draw(in: rect)
         }
-        else {
-            requestURL = image.getUrl(x: column, y: row, level: level, scale: scale)
+        else if let requestURL = image.getUrl(x: column, y: row, level: level, scale: scale) {
             URLSession.shared.dataTask(with: requestURL, completionHandler: { (data, response, error) in
                 if data != nil , let image = UIImage(data: data!) {
                     self.imageCache[cacheKey] = image
@@ -98,7 +96,7 @@ class ITVTiledView: UIView {
 
         if displayTileBorders {
             UIColor.green.set()
-            context.setLineWidth(2)
+            context.setLineWidth(1)
             context.stroke(rect)
         }
     }
@@ -107,9 +105,13 @@ class ITVTiledView: UIView {
     fileprivate func initBackground() {
         if let imageUrl = image.getBackgroundUrl() {
             URLSession.shared.dataTask(with: imageUrl, completionHandler: { (data, response, error) in
-                if data != nil, let image = UIImage(data: data!) {
+                if data != nil,
+                    let image = UIImage(data: data!),
+                    let scaledImage = self.scaledImage(image: image, newSize: self.bounds.size) {
                     DispatchQueue.main.sync {
-                        self.backgroundColor = UIColor(patternImage: self.scaledImage(image: image, newSize: self.bounds.size))
+                        let originalScaleFactor = self.contentScaleFactor
+                        self.backgroundColor = UIColor(patternImage: scaledImage)
+                        self.contentScaleFactor = originalScaleFactor
                         self.setNeedsLayout()
                     }
                 }
@@ -118,11 +120,11 @@ class ITVTiledView: UIView {
     }
 
     // Resize UIImage to fit given size.
-    fileprivate func scaledImage(image: UIImage, newSize: CGSize) -> UIImage {
+    fileprivate func scaledImage(image: UIImage, newSize: CGSize) -> UIImage? {
         UIGraphicsBeginImageContextWithOptions(newSize, false, 0.0)
         image.draw(in: CGRect(origin: CGPoint.zero, size: newSize))
         let newImage = UIGraphicsGetImageFromCurrentImageContext()
         UIGraphicsEndImageContext()
-        return newImage!
+        return newImage
     }
 }

iOSTiledViewer/Classes/Zoomify/ZoomifyImageDescriptor.swift

@@ -65,12 +65,20 @@ struct ZoomifyImageDescriptor {
         return tilesForLevel[level]
     }
 
-    fileprivate mutating func saveZoomScales(_ originalSize: CGSize, _ aspectFitSize: CGSize, _ viewScale: CGFloat) {
+    fileprivate func numberOfTiles(_ level: CGFloat) -> Int {
+        return numberOfTiles(Int(level))
+    }
+
+    fileprivate mutating func saveZoomScales(_ originalSize: CGSize, _ aspectFitSize: CGSize) {
         let ratioW = originalSize.width / aspectFitSize.width
         let ratioH = originalSize.height / aspectFitSize.height
-        _zoomScales = [min(ratioW, ratioH)]
+        let minimumScale = min(ratioW, ratioH)
+        _zoomScales = [minimumScale]
         for i in 1...depth {
-            _zoomScales.append(CGFloat(powf(2, Float(i))))
+            let scale = CGFloat(powf(2, Float(i)))
+            if scale > minimumScale {
+                _zoomScales.append(scale)
+            }
         }
     }
 }
@@ -134,12 +142,14 @@ extension ZoomifyImageDescriptor: ITVImageDescriptor {
         return URL(string: "\(baseUrl)/\(group)/\(file).\(format)")
     }
 
-    mutating func sizeToFit(size: CGSize, zoomScale: CGFloat) -> CGSize {
-        let sum = Float(width + height)
-        let totalTiles = Float(numberOfTiles(2) - numberOfTiles(1))
-        let numTilesX = CGFloat(round(totalTiles / (sum / Float(width))))
-        let numTilesY = CGFloat(round(totalTiles / (sum / Float(height))))
-        let tile = _tileSize.width / zoomScale
+    mutating func sizeToFit(size: CGSize) -> CGSize {
+        // We have to
+        let area = Float(width * height)
+        let totalTiles = Float(tilesForLevel.last! - tilesForLevel[tilesForLevel.count-2])
+        let coeficient = sqrt(area / totalTiles)
+        let numTilesX = CGFloat( Float(width)/coeficient )
+        let numTilesY = CGFloat( Float(height)/coeficient )
+        let tile = _tileSize.width / Constants.SCREEN_SCALE
 
         let imageSize = CGSize(width: width, height: height)
         var aspectFitSize = CGSize(width: numTilesX*tile, height: numTilesY*tile)
@@ -152,7 +162,10 @@ extension ZoomifyImageDescriptor: ITVImageDescriptor {
             aspectFitSize.height = mW * imageSize.height
         }
 
-        saveZoomScales(size, aspectFitSize, zoomScale)
+        let trasnformation = Constants.SCREEN_SCALE/CGFloat(powf(2.0, Float(depth)))
+        aspectFitSize = aspectFitSize.applying(CGAffineTransform(scaleX: trasnformation, y: trasnformation))
+
+        saveZoomScales(size, aspectFitSize)
         return aspectFitSize
     }
 }