feat(android): stretch property

Author: farfromrefuge

packages/ui-cameraview/platforms/ios/src/NSCameraView.swift

@@ -50,6 +50,16 @@ public class NSCameraView: UIView, NextLevelVideoDelegate, NextLevelPhotoDelegat
       self.nextLevel?.previewLayer.frame = self.bounds
     }
   }
+
+
+  public var videoGravity: AVLayerVideoGravity {
+    get {
+      return self.nextLevel?.previewLayer.videoGravity
+    }
+    set {
+      self.nextLevel?.previewLayer.videoGravity = newValue
+    }
+  }
 
   public var flashMode: Int {
     get {

src/ui-cameraview/index.ios.ts

@@ -1,7 +1,26 @@
 import { TakePictureOptions } from '.';
-import { CameraViewBase, autoFocusProperty, flashModeProperty } from './index.common';
+import { CameraViewBase, ScaleType, autoFocusProperty, flashModeProperty, stretchProperty } from './index.common';
 import { File, Utils } from '@nativescript/core';
 
+function getScaleType(scaleType: ScaleType) {
+    if (typeof scaleType === 'string') {
+        switch (scaleType) {
+            case ScaleType.FitCenter:
+            case ScaleType.AspectFit:
+            case ScaleType.FitEnd:
+            case ScaleType.FitStart:
+                return AVLayerVideoGravityResizeAspect;
+            default:
+            case ScaleType.Center:
+            case ScaleType.Fill:
+            case ScaleType.AspectFill:
+                return AVLayerVideoGravityResizeAspectFill;
+        }
+    }
+
+    return AVLayerVideoGravityResizeAspectFill;
+}
+
 @NativeClass
 class ProcessRawVideoSampleBufferDelegateImpl extends NSObject implements ProcessRawVideoSampleBufferDelegate {
     cameraViewRenderToCustomContextWithImageBufferOnQueue(cameraView: NSCameraView, imageBuffer: any, queue: NSObject): void {}
@@ -231,4 +250,8 @@ export class CameraView extends CameraViewBase {
             this.nativeViewProtected.focusMode = value;
         }
     }
+
+    [stretchProperty.setNative](value) {
+        this.nativeViewProtected.videoGravity = (getScaleType(value));
+    }
 }

src/ui-cameraview/typings/ios.d.ts

@@ -32,6 +32,7 @@ declare class NSCameraView extends UIView {
     torchMode: number;
 
     videoDelegate: NSCameraViewVideoDelegate;
+    videoGravity: string;
 
     capturePhoto(): void;