PinchGestureRecognizer
A gesture recognizer that tracks a pinch gesture. A pinch gesture occurs when two pointer contacts are brought towards each other, or away from each other. This is useful in controls that implements a pinch to zoom interaction.
Using a PinchGestureRecognizer
A PinchGestureRecognizer can be attached to a control using the control's GestureRecognizers property.
<Image Stretch="UniformToFill"
Margin="5"
Name="image"
Source="/image.jpg">
<Image.GestureRecognizers>
<PinchGestureRecognizer/>
</Image.GestureRecognizers>
</Image>
image.GestureRecognizers.Add(new PinchGestureRecognizer());
The PinchGestureRegonizer raises a Gestures.PinchEvent when it detects the start of a pull gesture. When the pull ends, from the pointer being released or another gesture start, it raises a Gestures.PinchEndedEvent.
The Scale property in the args passed to the Gestures.PinchEvent event handler contains the relative size of the pinch since it started.
Binding Events
After the PinchGestureRecognizer has been added to your control, you need to bind them in your code behind either through an inline handler or to an event function:
image.AddHandler(Gestures.PinchEvent, (s, e) => { });
image.AddHandler(Gestures.PinchEndedEvent, (s, e) => { });
image.AddHandler(Gestures.PinchEvent, Image_PinchGesture);
image.AddHandler(Gestures.PinchEndedEvent, Image_PinchGestureEnded);
...
private void Image_PinchGesture(object? sender, PinchGestureEventArgs e) { }
private void Image_PinchGestureEnded(object? sender, PinchGestureEndedEventArgs e) { }
If your event handles the gesture completely, you can mark the event as handled by setting:
e.Handled = true;