Adding RadialGradientBrush in uno library

[AghaKhan]

Current behavior

My Uno library works fine until I add RadialGradientBrush to my project. To resolve this problem, I installed Microsoft.UI.Xaml package, which broke all the packages monoandroid10.0, MonoAndroid11.0, xamarinios10, and xamarinmac20. What is the solution to add RadialGradientBrush, and should it work on all platforms?
I am Microsoft Visual Studio Professional 2019 Version 16.11.2

Expected behavior

It should work on all platforms.

How to reproduce it (as minimally and precisely as possible)

I visited https://playground.platform.uno and add RadialGradientBrush as a Resource, but unable to find
SimpleExample

Workaround

No response

Works on UWP/WinUI

No response

Environment

No response

NuGet package version(s)

No response

Affected platforms

No response

IDE

No response

IDE version

No response

Relevant plugins

No response

Anything else we need to know?

No response

[AghaKhan]

SimpleExample

[jeromelaban]

RadialGradientBrush is part of a different namespace, you'll need to add an additional declaration in your XAML file.

Here's an example from the Microsoft documentation:

<Page
  xmlns:media="using:Microsoft.UI.Xaml.Media">

  <Rectangle Width="200" Height="200">
      <Rectangle.Fill>
          <media:RadialGradientBrush>
              <GradientStop Color="Blue" Offset="0.0" />
              <GradientStop Color="Yellow" Offset="0.2" />
              <GradientStop Color="LimeGreen" Offset="0.4" />
              <GradientStop Color="LightBlue" Offset="0.6" />
              <GradientStop Color="Blue" Offset="0.8" />
              <GradientStop Color="LightGray" Offset="1" />
          </media:RadialGradientBrush>
      </Rectangle.Fill>
  </Rectangle>
</Page>

[AghaKhan]

uap10.0.18362;netstandard2.0;xamarinios10;xamarinmac20;MonoAndroid11.0;monoandroid10.0 true %(Filename) Designer

[AghaKhan]

When I tried to add (TargetFramework is not defined. Also adding

[jeromelaban]

Win2D is supported in Uno, indeed, which is why you are seeing these errors. You can still use it for uap10.0.xxx using <ItemGroup Condition="'$(TargetFramework)'=='uap10.0.18362'">, but for Uno targets you'll need to use something else like SkiaSharp. You can find a sample here.

By the way, you can paste your images directly in the GitHub text editor, same for the zip files for sources. This way, it will stay with the issue and not in your one drive, if someone looks for this thread after a while.

[AghaKhan]

I have downloaded SkiaSharp source code and searched RadialGradientBrush, which I didn't find, so SkiaSharp will not help to resolve the problem of RadialGradientBrush. I don't want to add xmlns:media="using:Microsoft.UI.Xaml.Media" because it is only for UWP and unsuitable for rest of platforms. Can you provide me a sample (draw a circle with RadialGradientBrush) which is good for all platforms? Best regards Agha

[jeromelaban]

RadialGradientBrush is supported on all platforms. Can you explain why you need to add Win2D ?

[AghaKhan]

The objective of using Uno Platform is to work across all Platforms with one code. If we are only talking about UWP, then it doesn’t make any sense to use Uno Platform. I have written many applications (UWP) where I am using Win2D and without Win2D namespace support of RadialGradientBrush is absent. Microsoft wants to bring Win2D with UWP because RadialGradientBrush is available natively. I just realized if I add Win2D none of Platform will work. I requested a sample (A circle or rectangle) where RadialGradientBrush is available across all Platforms. Indeed, if RadialGradientBrush is available across all Platforms then it must be one line code. Can you provide few lines of code about RadialGradientBrush which should work all Platforms?

[jeromelaban]

Can you update your sample with all the adjustments made in this thread? It looks like there's some misunderstanding in what should be done.

[AghaKhan]

OctagonApp.zip
Kindly look .\OctagonApp\ControlLib\OctagonControl.xaml
If you are using RadialGradientBrush in your code then you might Microsoft provided code. This code works fine if you add win2D to your project because RadialGradientBrush is defined inside Win2D
xmlns:media="using:Microsoft.UI.Xaml.Media">

Your application will not compile for any Platform if you add Win2D in your application.
Any help will be very much appreciated.
Best regards Agha Khan

[jeromelaban]

Thanks. As I mentioned in #6902 (reply in thread), you need this reference:

<ItemGroup Condition="'$(TargetFramework)'=='uap10.0.18362'">
  <PackageReference Include="Microsoft.UI.Xaml" Version="2.5.0" />
</ItemGroup>

in your controllib.csproj. Otherwise, RadialGradientBrush won't be available for uap10.0.x as it is defined in the Microsoft.UI.Xaml nuget package, as well as add the media:xmlns at the top.

Please see in the attached archive for the complete changes: 6902-ControlLib.zip

[AghaKhan]

Indeed, it worked, but without your help how someone can resolve those problem. Regards Agha