internal void DoFocus(Rect r)
{
var handler = new FocusCallback(this);
//CANCEL PREVIOUS AUTOFOCUS
previewSession.StopRepeating();
previewBuilder.Set(CaptureRequest.ControlAfMode, (int)ControlAFMode.Off);
previewBuilder.Set(CaptureRequest.ControlAfTrigger, (int)ControlAFTrigger.Cancel);
previewSession.Capture(previewBuilder.Build(), handler, backgroundHandler);
previewBuilder.Set(CaptureRequest.ControlMode, (int)ControlMode.Auto);
previewBuilder.Set(CaptureRequest.ControlAfMode, (int)ControlAFMode.Auto);
previewBuilder.Set(CaptureRequest.ControlAfTrigger, (int)ControlAFTrigger.Start);
MeteringRectangle rect = new MeteringRectangle(r, MeteringRectangle.MeteringWeightMax);
previewBuilder.SetTag("FOCUS");
previewBuilder.Set(CaptureRequest.ControlAfRegions, new MeteringRectangle[] { rect });
previewSession.Capture(previewBuilder.Build(), handler, backgroundHandler);
}
public void ChangeFocusPoint(Xamarin.Forms.Point e)
{
string cameraId = _manager.GetCameraIdList()[0];
// To get a list of available sizes of camera preview, we retrieve an instance of
// StreamConfigurationMap from CameraCharacteristics
CameraCharacteristics characteristics = _manager.GetCameraCharacteristics(cameraId);
var rect = characteristics.Get(CameraCharacteristics.SensorInfoActiveArraySize) as Rect;
var size = characteristics.Get(CameraCharacteristics.SensorInfoPixelArraySize) as Size;
int areaSize = 200;
int right = rect.Right;
int bottom = rect.Bottom;
int viewWidth = _cameraTexture.Width;
int viewHeight = _cameraTexture.Height;
int ll, rr;
Rect newRect;
int centerX = (int)e.X;
int centerY = (int)e.Y;
ll = ((centerX * right) - areaSize) / viewWidth;
rr = ((centerY * bottom) - areaSize) / viewHeight;
int focusLeft = Clamp(ll, 0, right);
int focusBottom = Clamp(rr, 0, bottom);
newRect = new Rect(focusLeft, focusBottom, focusLeft + areaSize, focusBottom + areaSize);
MeteringRectangle meteringRectangle = new MeteringRectangle(newRect, 500);
MeteringRectangle[] meteringRectangleArr = { meteringRectangle };
_previewBuilder.Set(CaptureRequest.ControlAfTrigger, (int)ControlAFTrigger.Cancel);
_previewBuilder.Set(CaptureRequest.ControlAeRegions, meteringRectangleArr);
_previewBuilder.Set(CaptureRequest.ControlAfTrigger, (int)ControlAFTrigger.Start);
UpdatePreview();
}
