Fix preview size for camera view on Androud (#723) (#731)

- Fix based on sample implementation for Camera2 API from Google
- https://github.com/android/camera-samples/blob/4aac9c7763c285d387194a558416a4458f29e275/CameraXTfLite/utils/src/main/java/com/example/android/camera/utils/CameraSizes.kt#L50-L78

Co-authored-by: Eugen Richter <eugen.richter@amcsgroup.com>
Co-authored-by: Gerald Versluis <gerald.versluis@microsoft.com>

samples/XCT.Sample/Pages/Views/CameraViewPage.xaml

@@ -24,6 +24,7 @@
  IsEnabled="False"
  Maximum="10"
  Minimum="1"
+ HorizontalOptions="FillAndExpand"
  ValueChanged="ZoomSlider_ValueChanged"
  Value="1" />
  </StackLayout>

src/CommunityToolkit/Xamarin.CommunityToolkit/Views/CameraView/Android/CameraFragment.android.cs

@@ -36,12 +36,19 @@
 using Xamarin.Forms;
 using Xamarin.Forms.Platform.Android;
 using Camera = Android.Hardware.Camera;
+using Math = System.Math;
 using Rect = Android.Graphics.Rect;
+using APoint = Android.Graphics.Point;
 
 namespace Xamarin.CommunityToolkit.UI.Views
 {
  class CameraFragment : Fragment, TextureView.ISurfaceTextureListener
  {
+ // Max preview width that is guaranteed by Camera2 API
+ const int MAX_PREVIEW_HEIGHT = 1080;
+ // Max preview height that is guaranteed by Camera2 API
+ const int MAX_PREVIEW_WIDTH = 1920;
+
  CameraDevice device;
  CaptureRequest.Builder sessionBuilder;
  CameraCaptureSession session;
@@ -222,14 +229,42 @@ public async Task RetrieveCameraDevice(bool force = false)
  }
  Element.MaxZoom = maxDigitalZoom = (float)characteristics.Get(CameraCharacteristics.ScalerAvailableMaxDigitalZoom);
  activeRect = (Rect)characteristics.Get(CameraCharacteristics.SensorInfoActiveArraySize);
+ sensorOrientation = (int)characteristics.Get(CameraCharacteristics.SensorOrientation);
+
+ var displaySize = new APoint();
+ Activity.WindowManager.DefaultDisplay.GetSize(displaySize);
+ var rotatedViewWidth = texture.Width;
+ var rotatedViewHeight = texture.Height;
+ var maxPreviewWidth = displaySize.X;
+ var maxPreviewHeight = displaySize.Y;
+
+ if (sensorOrientation == 90 || sensorOrientation == 270)
+ {
+ rotatedViewWidth = texture.Height;
+ rotatedViewHeight = texture.Width;
+ maxPreviewWidth = displaySize.Y;
+ maxPreviewHeight = displaySize.X;
+ }
+
+ if (maxPreviewHeight > MAX_PREVIEW_HEIGHT)
+ {
+ maxPreviewHeight = MAX_PREVIEW_HEIGHT;
+ }
+
+ if (maxPreviewWidth > MAX_PREVIEW_WIDTH)
+ {
+ maxPreviewWidth = MAX_PREVIEW_WIDTH;
+ }
+
  photoSize = GetMaxSize(map.GetOutputSizes((int)ImageFormatType.Jpeg));
  videoSize = GetMaxSize(map.GetOutputSizes(Class.FromType(typeof(MediaRecorder))));
  previewSize = ChooseOptimalSize(
  map.GetOutputSizes(Class.FromType(typeof(SurfaceTexture))),
- texture.Width,
- texture.Height,
+ rotatedViewWidth,
+ rotatedViewHeight,
+ maxPreviewWidth,
+ maxPreviewHeight,
  cameraTemplate == CameraTemplate.Record ? videoSize : photoSize);
- sensorOrientation = (int)characteristics.Get(CameraCharacteristics.SensorOrientation);
  cameraType = (LensFacing)(int)characteristics.Get(CameraCharacteristics.LensFacing);
 
  if (Resources.Configuration.Orientation == AOrientation.Landscape)
@@ -923,17 +958,25 @@ ASize GetMaxSize(ASize[] imageSizes)
  }
 
  // chooses the smallest one whose width and height are at least as large as the respective requested values
- ASize ChooseOptimalSize(ASize[] choices, int width, int height, ASize aspectRatio)
+ ASize ChooseOptimalSize(ASize[] choices, int width, int height, int maxWidth, int maxHeight, ASize aspectRatio)
  {
  var bigEnough = new List<ASize>();
+ var notBigEnough = new List<ASize>();
  var w = aspectRatio.Width;
  var h = aspectRatio.Height;
  foreach (var option in choices)
  {
- if (option.Height == option.Width * h / w &&
-  option.Width >= width && option.Height >= height)
+ if (option.Width <= maxWidth && option.Height <= maxHeight &&
+   option.Height == option.Width * h / w)
  {
- bigEnough.Add(option);
+ if (option.Width >= width && option.Height >= height)
+ {
+ bigEnough.Add(option);
+ }
+ else
+ {
+ notBigEnough.Add(option);
+ }
  }
  }
 
@@ -943,11 +986,15 @@ ASize ChooseOptimalSize(ASize[] choices, int width, int height, ASize aspectRati
  var minArea = bigEnough.Min(s => s.Width * s.Height);
  return bigEnough.First(s => s.Width * s.Height == minArea);
  }
- else
+
+ if (notBigEnough.Count > 0)
  {
- LogError("Couldn't find any suitable preview size");
- return choices[0];
+ var maxArea = notBigEnough.Max(s => s.Height * s.Width);
+ return notBigEnough.First(s => s.Height * s.Width == maxArea);
  }
+
+ LogError("Couldn't find any suitable preview size");
+ return choices[0];
  }
  #endregion
  }