SkiaSharp.Views.Maui.SkCanvasView is not drawing on physical iOS devices

[whodges]

Discussed in https://github.com/mono/SkiaSharp/discussions/2293

^{Originally posted by whodges October 25, 2022} Hello,

I've been trying to get SkCanvasView working on my iPad, and I've run into the same problem as described here: https://github.com/mono/SkiaSharp/issues/341, but with MAUI. On Windows and in the simulators, the canvas in my sample app works (i.e., it paints and show up as a red square). On my physical iPad, the canvas never fires the PaintSurface event, and so ends up black. I can tell it's there at least because of the position of the 'Invalidate' button I added; it's just not drawing.

My MainPage.xaml:

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:skia="clr-namespace:SkiaSharp.Views.Maui.Controls;assembly=SkiaSharp.Views.Maui.Controls"
             x:Class="MauiSample.MainPage">

    <ScrollView>
        <VerticalStackLayout>

            <skia:SKCanvasView
                x:Name="SampleCanvas"
                EnableTouchEvents="true"
                Touch="SampleCanvas_Touch"
                PaintSurface="SampleCanvas_PaintSurface"
                HeightRequest="512"
                WidthRequest="512">
            </skia:SKCanvasView>

            <Button
                x:Name="InvalidateBtn"
                Text="Invalidate"
                SemanticProperties.Hint="Invalidates the canvas"
                Clicked="InvalidateBtn_Clicked"
                HorizontalOptions="Center" >
            </Button>

        </VerticalStackLayout>
    </ScrollView>

</ContentPage>

My MainPage.xaml.cs:

using SkiaSharp;
using SkiaSharp.Views.Maui;

namespace MauiSample;

public partial class MainPage : ContentPage
{
    public MainPage()
    {
        InitializeComponent();
    }

    private void SampleCanvas_Touch(object sender, SKTouchEventArgs e)
    {
        SampleCanvas.InvalidateSurface();
    }

    private void SampleCanvas_PaintSurface(object sender, SKPaintSurfaceEventArgs e)
    {
        e.Surface.Canvas.DrawColor(new SKColor(255, 0, 0));
        return;
    }

    private void InvalidateBtn_Clicked(object sender, EventArgs e)
    {
        SampleCanvas.InvalidateSurface();
    }
}

And I've called UseSkiaSharp() in the app builder.

For the record, the Touch event isn't firing on the iPad either (it does on Windows). I'm using Visual Studio Pro 17.4.0 Preview 4.0, and Skia.Views.Maui.Controls 2.88.3. Any insight is appreciated; perhaps I'm missing something obvious. Screenshots of my output:

Windows:

iPad:

EDIT: Fixed my crappy code block formatting.

[AlexanderSCK]

Same issue here on an iphone 8, iOS version 16. Did you find a potential workaround?

[whodges]

Nope! No luck yet - I'll be circling back around to this in the coming week. Doesn't it suck when you find a post that describes exactly the same problem you're having, but has no actual answer? :)

[AlexanderSCK]

Yes exactly but nobody from Skia seems to want to help with this breaking issue.

[beto-rodriguez]

From:

https://github.com/beto-rodriguez/LiveCharts2/issues/800 https://github.com/Mapsui/Mapsui/issues/1872

Here is a workaround: https://github.com/beto-rodriguez/LiveCharts2/issues/800#issuecomment-1672992578

[Nebula-Developer]

Also broken on my MacBook running MacOS Sonoma. Did you ever find a fix?