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;
}
}
