feat: support async crop (#232)

* feat: support async crop * fix: hide activityIndicator after the async crop is done fix a typo * fix: put UIKit related code in main thread
guoyingtao · Nov 14, 2022 · 69e5640 · 69e5640
1 parent 21604f0
commit 69e5640
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Showing 4 changed files with 79 additions and 21 deletions.
diff --git a/Example/ViewController.swift b/Example/ViewController.swift
@@ -36,6 +36,7 @@ class ViewController: UIViewController, CropViewControllerDelegate {
         }
 
         var config = Mantis.Config()
+        config.cropMode = .async
         config.cropToolbarConfig.toolbarButtonOptions = [.clockwiseRotate, .reset, .ratio, .horizontallyFlip]
         let cropViewController = Mantis.cropViewController(image: image,
                                                            config: config)

diff --git a/Sources/Mantis/Config.swift b/Sources/Mantis/Config.swift
@@ -32,6 +32,14 @@ public class LocalizationConfig {
 
 // MARK: - Config
 public struct Config {
+
+    public enum CropMode {
+        case sync
+        case async // We may need this mode when cropping big images
+    }
+
+    public var cropMode: CropMode = .sync
+
     public var cropViewConfig = CropViewConfig()    
     public var cropToolbarConfig: CropToolbarConfigProtocol = CropToolbarConfig()
 

diff --git a/Sources/Mantis/CropView/CropView.swift b/Sources/Mantis/CropView/CropView.swift
@@ -69,6 +69,23 @@ class CropView: UIView {
 
     private var cropFrameKVO: NSKeyValueObservation?
 
+    lazy private var activityIndicator: UIActivityIndicatorView = {
+        let activityIndicator = UIActivityIndicatorView(frame: .zero)
+        activityIndicator.color = .white
+        let indicatorSize: CGFloat = 100
+        activityIndicator.transform = CGAffineTransform(scaleX: 2.0, y: 2.0)
+
+        addSubview(activityIndicator)
+        activityIndicator.translatesAutoresizingMaskIntoConstraints = false
+
+        activityIndicator.centerXAnchor.constraint(equalTo: centerXAnchor).isActive = true
+        activityIndicator.centerYAnchor.constraint(equalTo: centerYAnchor).isActive = true
+        activityIndicator.widthAnchor.constraint(equalToConstant: indicatorSize).isActive = true
+        activityIndicator.heightAnchor.constraint(equalToConstant: indicatorSize).isActive = true
+
+        return activityIndicator
+    } ()
+
     deinit {
         print("CropView deinit.")
     }
@@ -577,8 +594,25 @@ extension CropView {
 extension CropView {
     func crop(_ image: UIImage) -> CropOutput {
         let cropInfo = getCropInfo()
+        let cropOutput = (image.crop(by: cropInfo), makeTransformation(), cropInfo)
+        return addImageMask(to: cropOutput)
+    }
+
+    func asyncCrop(_ image: UIImage, completion: @escaping (CropOutput) -> Void) {
+        let cropInfo = getCropInfo()
+        let cropOutput = (image.crop(by: cropInfo), makeTransformation(), cropInfo)
 
-        let transformation = Transformation(
+        DispatchQueue.global(qos: .userInteractive).async {
+            let maskedCropOutput = self.addImageMask(to: cropOutput)
+            DispatchQueue.main.async {
+                self.activityIndicator.isHidden = true
+                completion(maskedCropOutput)
+            }
+        }
+    }
+
+    func makeTransformation() -> Transformation {
+        Transformation(
             offset: scrollView.contentOffset,
             rotation: getTotalRadians(),
             scale: scrollView.zoomScale,
@@ -587,9 +621,13 @@ extension CropView {
             maskFrame: gridOverlayView.frame,
             scrollBounds: scrollView.bounds
         )
+    }
+
+    func addImageMask(to cropOutput: CropOutput) -> CropOutput {
+        let (croppedImage, transformation, cropInfo) = cropOutput
 
-        guard let croppedImage = image.crop(by: cropInfo) else {
-            return (nil, transformation, cropInfo)
+        guard let croppedImage = croppedImage else {
+            return cropOutput
         }
 
         switch cropViewConfig.cropShapeType {
@@ -700,6 +738,17 @@ extension CropView {
     func crop() -> CropOutput {
         return crop(image)
     }
+
+    /// completion is called in the main thread
+    func asyncCrop(completion: @escaping (_ cropOutput: CropOutput) -> Void ) {
+        activityIndicator.isHidden = false
+        activityIndicator.startAnimating()
+
+        asyncCrop(image) { [weak self] cropOutput  in
+            self?.activityIndicator.isHidden = true
+            completion(cropOutput)
+        }
+    }
 
     func handleDeviceRotated() {
         viewModel.resetCropFrame(by: getInitialCropBoxRect())

diff --git a/Sources/Mantis/CropViewController/CropViewController.swift b/Sources/Mantis/CropViewController/CropViewController.swift
@@ -433,16 +433,7 @@ public class CropViewController: UIViewController {
     }
 
     private func handleCrop() {
-        let cropResult = cropView.crop()
-        guard let image = cropResult.croppedImage else {
-            delegate?.cropViewControllerDidFailToCrop(self, original: cropView.image)
-            return
-        }
-
-        delegate?.cropViewControllerDidCrop(self,
-                                                 cropped: image,
-                                                 transformation: cropResult.transformation,
-                                                 cropInfo: cropResult.cropInfo)        
+        crop()
     }
 }
 
@@ -569,16 +560,25 @@ extension CropViewController: CropToolbarDelegate {
 // API
 extension CropViewController {
     public func crop() {
-        let cropResult = cropView.crop()
-        guard let image = cropResult.croppedImage else {
-            delegate?.cropViewControllerDidFailToCrop(self, original: cropView.image)
-            return
+        switch config.cropMode {
+        case .sync:
+            let cropOutput = cropView.crop()
+            handleCropOutput(cropOutput)
+        case .async:
+            cropView.asyncCrop(completion: handleCropOutput)
         }
 
-        delegate?.cropViewControllerDidCrop(self,
-                                            cropped: image,
-                                            transformation: cropResult.transformation,
-                                            cropInfo: cropResult.cropInfo)
+        func handleCropOutput(_ cropOutput: CropOutput) {
+            guard let image = cropOutput.croppedImage else {
+                delegate?.cropViewControllerDidFailToCrop(self, original: cropView.image)
+                return
+            }
+
+            delegate?.cropViewControllerDidCrop(self,
+                                                cropped: image,
+                                                transformation: cropOutput.transformation,
+                                                cropInfo: cropOutput.cropInfo)
+        }
     }
 
     public func process(_ image: UIImage) -> UIImage? {