//Forces the rotation to be about the center of the manipulation target.
public static void RotateAboutCenter(object sender, FilterManipulationEventArgs args)
{
var inputProcessor = sender as InputProcessor;
var target = inputProcessor.Target;
var rect = target.RenderTransform.TransformBounds(
new Windows.Foundation.Rect(0, 0, target.ActualWidth, target.ActualHeight));
args.Pivot = new Windows.Foundation.Point
{
X = rect.Left + (rect.Width / 2),
Y = rect.Top + (rect.Height / 2)
};
}
public static void ClampCenterOfMass(object sender, FilterManipulationEventArgs args)
{
var inputProcessor = sender as InputProcessor;
var target = inputProcessor.Target;
var container = inputProcessor.Reference;
var rect = target.RenderTransform.TransformBounds(
new Windows.Foundation.Rect(0, 0, target.ActualWidth, target.ActualHeight));
var centerOfMass = new Windows.Foundation.Point
{
X = rect.Left + (rect.Width / 2),
Y = rect.Top + (rect.Height / 2)
};
var transform = new Windows.UI.Xaml.Media.CompositeTransform
{
CenterX = args.Pivot.X,
CenterY = args.Pivot.Y,
Rotation = args.Delta.Rotation,
ScaleX = args.Delta.Scale,
ScaleY = args.Delta.Scale,
TranslateX = args.Delta.Translation.X,
TranslateY = args.Delta.Translation.Y
};
var transformedCenterOfMass = transform.TransformPoint(centerOfMass);
if (transformedCenterOfMass.X < 0 || transformedCenterOfMass.X > container.ActualWidth ||
transformedCenterOfMass.Y < 0 || transformedCenterOfMass.Y > container.ActualHeight)
{
args.Delta = new Windows.UI.Input.ManipulationDelta
{
Rotation = 0F,
Scale = 1F,
Translation = new Windows.Foundation.Point(0, 0)
};
}
}
// Forces pixels of the manipulation target to remain inside its container.
public static void Clamp(object sender, FilterManipulationEventArgs args)
{
var inputProcessor = sender as InputProcessor;
var target = inputProcessor.Target;
var container = inputProcessor.Reference;
// Get the bounding box of the manipulation target, expressed in the coordinate system of its container
var rect = target.RenderTransform.TransformBounds(
new Windows.Foundation.Rect(0, 0, target.ActualWidth, target.ActualHeight));
var translate = new Windows.Foundation.Point
{
X = args.Delta.Translation.X,
Y = args.Delta.Translation.Y
};
if ((args.Delta.Translation.X > 0 && args.Delta.Translation.X > container.ActualWidth - rect.Left - ManipulationFilter.TargetMinInside) ||
(args.Delta.Translation.X < 0 && args.Delta.Translation.X < ManipulationFilter.TargetMinInside - rect.Right) ||
(args.Delta.Translation.Y > 0 && args.Delta.Translation.Y > container.ActualHeight - rect.Top - ManipulationFilter.TargetMinInside) ||
(args.Delta.Translation.Y < 0 && args.Delta.Translation.Y < ManipulationFilter.TargetMinInside - rect.Bottom))
{
translate.X = 0;
translate.Y = 0;
}
float scale = args.Delta.Scale < 1F ?
(float)System.Math.Max(ManipulationFilter.TargetMinSize / System.Math.Min(rect.Width, rect.Height), args.Delta.Scale) :
(float)System.Math.Min(ManipulationFilter.TargetMaxSize / System.Math.Max(rect.Width, rect.Height), args.Delta.Scale);
args.Delta = new Windows.UI.Input.ManipulationDelta
{
Expansion = args.Delta.Expansion,
Rotation = args.Delta.Rotation,
Scale = scale,
Translation = translate
};
}
private void OnManipulationUpdated(Windows.UI.Input.GestureRecognizer sender, Windows.UI.Input.ManipulationUpdatedEventArgs args)
{
var filteredArgs = new FilterManipulationEventArgs(args);
if (OnFilterManipulation != null)
{
OnFilterManipulation(this, filteredArgs);
}
// Update the transform
this._previousTransform.Matrix = _transform.Value;
this._deltaTransform.CenterX = filteredArgs.Pivot.X;
this._deltaTransform.CenterY = filteredArgs.Pivot.Y;
this._deltaTransform.Rotation = filteredArgs.Delta.Rotation;
this._deltaTransform.ScaleX = _deltaTransform.ScaleY = filteredArgs.Delta.Scale;
this._deltaTransform.TranslateX = filteredArgs.Delta.Translation.X;
this._deltaTransform.TranslateY = filteredArgs.Delta.Translation.Y;
}