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mauiskiasharp

Detect mouse wheel over SKCanvasView

I have a MAUI application for viewing images. Images are rendered using SKCanvasView. I wanted to add zoom functionality which, on windows, would work using mouse wheel. However I wasn't able to find a way to do it. The closes gesture to what I'm looking for seems to be PinchGesture, but mouse wheel doesn't get translated to it. I found that some controls have PointerWheelChanged event, but SKCanvasView is not one of them. I also heard of writing custom dependency services and handlers for this purpose, but no actual examples of such for mouse wheel.

I have a hunch that this is impossible in MAUI for now (unless I go really low level and tap into Windows APIs), but if someone knows a way how to make this work, I would appreciate it.

Solution

  • You can add the PointerWheelChanged event to the windows platform view of the SKCanvasView. Such as：

    In the xaml:

    <sk:SKCanvasView x:Name="skview" HeightRequest="300" WidthRequest="300"/>

    And in the page's code behind:

        protected override void OnHandlerChanged()
    {
        base.OnHandlerChanged();
#if WINDOWS
            var view = skview.Handler.PlatformView as SkiaSharp.Views.Windows.SKXamlCanvas;
            view.PointerWheelChanged += ( s, e) =>
            {

            };
#endif
      }

    I have tested this and it can detect the mouse wheel over SKCanvasView.