Reputation: 45
I would like to rotate the border with inertia. Where do I leave something out?
MainPage.xaml:
<Grid>
<Border x:Name="ManipulationBorder" Width="200" Height="200" HorizontalAlignment="Center" VerticalAlignment="Center" Background="Red"/>
</Grid>
MainPage.xaml.cs:
private TransformGroup transforms;
private MatrixTransform previousTransform;
private CompositeTransform deltaTransform;
public MainPage()
{
this.InitializeComponent();
InitManipulationTransforms();
ManipulationBorder.ManipulationDelta += new ManipulationDeltaEventHandler(ManipulateMe_ManipulationDelta);
ManipulationBorder.ManipulationMode =
ManipulationModes.TranslateX |
ManipulationModes.TranslateY |
ManipulationModes.Rotate |
ManipulationModes.TranslateInertia |
ManipulationModes.RotateInertia;
}
private void InitManipulationTransforms()
{
transforms = new TransformGroup();
previousTransform = new MatrixTransform() { Matrix = Matrix.Identity };
deltaTransform = new CompositeTransform();
transforms.Children.Add(previousTransform);
transforms.Children.Add(deltaTransform);
ManipulationBorder.RenderTransform = transforms;
}
private void ManipulateMe_ManipulationDelta(object sender, ManipulationDeltaRoutedEventArgs e)
{
previousTransform.Matrix = transforms.Value;
// Center point for rotation
Point center = previousTransform.TransformPoint(new Point(e.Position.X, e.Position.Y));
deltaTransform.CenterX = center.X;
deltaTransform.CenterY = center.Y;
// Rotation
deltaTransform.Rotation = e.Delta.Rotation;
}
When I actually go to apply delta rotation in ManipulationDeltaRoutedEventArgs it does not work. Where am I wrong?
Thanks in advance.
Upvotes: 0
Views: 301
Reputation: 32785
When I actually go to apply delta rotation in ManipulationDeltaRoutedEventArgs it does not work. Where am I wrong?
The standard touch-based rotation requires two touch points or more:
For single touch rotation you need fix the center of deltaTransform firstly.
You need recalculate the Angle
has been changed with single touch.
you will know the value of Angle = a1 - a2
.
private void Right_ManipulationDelta(object sender, ManipulationDeltaRoutedEventArgs e)
{
var x = this.RightRotateTransform.CenterX - e.Position.X;
var y = this.RightRotateTransform.CenterY - e.Position.Y;
double a1 = Math.Atan(y / x);
double a2 = Math.Atan((e.Delta.Translation.Y - y) / (x - e.Delta.Translation.X));
this.RightRotateTransform.Angle += a1 - a2;
}
Upvotes: 1