void OnRunningChanged(NSObservedChange change)
{
var running = ((NSNumber)change.NewValue).BoolValue;
if (!running)
{
return;
}
DispatchQueue.MainQueue.DispatchAsync(() => {
// If the region of interest view's region of interest has not
// been initialized yet, let's set an inital region of interest
// that is 80% of the shortest side by 25% of the longest side
// and centered in the root view.
if (RegionOfInterest.IsEmpty)
{
var width = NMath.Min(Frame.Width, Frame.Height) * 0.8f;
var height = NMath.Max(Frame.Width, Frame.Height) * 0.25f;
var newRegionOfInterest = Frame.Inset(Frame.GetMidX() - width / 2, Frame.GetMidY() - height / 2);
SetRegionOfInterestWithProposedRegionOfInterest(newRegionOfInterest);
}
if (running)
{
SetRegionOfInterestWithProposedRegionOfInterest(RegionOfInterest);
RegionOfInterestDidChange?.Invoke(this, EventArgs.Empty);
}
});
}
void ResizeRegionOfInterestWithGestureRecognizer(UIPanGestureRecognizer pan)
{
var touchLocation = pan.LocationInView(pan.View);
var oldRegionOfInterest = RegionOfInterest;
switch (pan.State)
{
case UIGestureRecognizerState.Began:
// When the gesture begins, save the corner that is closes to
// the resize region of interest gesture recognizer's touch location.
currentControlCorner = CornerOfRect(oldRegionOfInterest, touchLocation);
break;
case UIGestureRecognizerState.Changed:
var newRegionOfInterest = oldRegionOfInterest;
switch (currentControlCorner)
{
case ControlCorner.None:
// Update the new region of interest with the gesture recognizer's translation.
var translation = pan.TranslationInView(pan.View);
// Move the region of interest with the gesture recognizer's translation.
if (RegionOfInterest.Contains(touchLocation))
{
newRegionOfInterest.X += translation.X;
newRegionOfInterest.Y += translation.Y;
}
// If the touch location goes outside the preview layer,
// we will only translate the region of interest in the
// plane that is not out of bounds.
var normalizedRect = new CGRect(0, 0, 1, 1);
if (!normalizedRect.Contains(VideoPreviewLayer.PointForCaptureDevicePointOfInterest(touchLocation)))
{
if (touchLocation.X < RegionOfInterest.GetMinX() || touchLocation.X > RegionOfInterest.GetMaxX())
{
newRegionOfInterest.Y += translation.Y;
}
else if (touchLocation.Y < RegionOfInterest.GetMinY() || touchLocation.Y > RegionOfInterest.GetMaxY())
{
newRegionOfInterest.X += translation.X;
}
}
// Set the translation to be zero so that the new gesture
// recognizer's translation is in respect to the region of
// interest's new position.
pan.SetTranslation(CGPoint.Empty, pan.View);
break;
case ControlCorner.TopLeft:
newRegionOfInterest = new CGRect(touchLocation.X, touchLocation.Y,
oldRegionOfInterest.Width + oldRegionOfInterest.X - touchLocation.X,
oldRegionOfInterest.Height + oldRegionOfInterest.Y - touchLocation.Y);
break;
case ControlCorner.TopRight:
newRegionOfInterest = new CGRect(newRegionOfInterest.X,
touchLocation.Y,
touchLocation.X - newRegionOfInterest.X,
oldRegionOfInterest.Height + newRegionOfInterest.Y - touchLocation.Y);
break;
case ControlCorner.BottomLeft:
newRegionOfInterest = new CGRect(touchLocation.X, oldRegionOfInterest.Y,
oldRegionOfInterest.Width + oldRegionOfInterest.X - touchLocation.X,
touchLocation.Y - oldRegionOfInterest.Y);
break;
case ControlCorner.BottomRight:
newRegionOfInterest = new CGRect(oldRegionOfInterest.X, oldRegionOfInterest.Y,
touchLocation.X - oldRegionOfInterest.X,
touchLocation.Y - oldRegionOfInterest.Y);
break;
}
// Update the region of intresest with a valid CGRect.
SetRegionOfInterestWithProposedRegionOfInterest(newRegionOfInterest);
break;
case UIGestureRecognizerState.Ended:
RegionOfInterestDidChange?.Invoke(this, EventArgs.Empty);
// Reset the current corner reference to none now that the resize.
// gesture recognizer has ended.
currentControlCorner = ControlCorner.None;
break;
default:
return;
}
}