[QUESTION] How to convert a SKRuntimeEffect to SKColorFilter?

[dbriard]

Hi,
I am using SkiaSharp 2.88.3.
There is a function called ToColorFilter(uniforms, children) however I cannot understand how it is supposed to work.

The only example I found in SKRuntimeEffectTest.cs is not working and cf1 is null.

var src = @"
uniform shader input;
half4 main() {
    return sample(input);
}";

			using var img = SKImage.FromEncodedData(Path.Combine(PathToImages, "baboon.jpg"));
			canvas.DrawImage(img, 0, 0);

			using var effect = SKRuntimeEffect.Create(src, out var errorText);
			Assert.Null(errorText);
			Assert.NotNull(effect);

			var cf1 = effect.ToColorFilter();

I can only get a non-null ColorFilter using this Shader... but it is very useful.

half4 main(float2 p) {
    return half4(0);
}

I suppose there are limitations but what are they?
I need to access to the main image (input?), and possibly to other images to combine them, or textures to use as Look-up tables.
Can I do that using a custom color filter?

Thanks for helping.

[mattleibow]

As of today, SKRuntimeEffect is not supported on a raster/bitmap canvas and only on the GPU.

[mattleibow]

Duplicate of #1822

[dbriard]

As of today, SKRuntimeEffect is not supported on a raster/bitmap canvas and only on the GPU.

Hi @mattleibow
Thank you for your answer, however this one is not about rendering in bitmap, but how to SKRuntimeEffect's ToColorFilter function.
I implemented Lut3D effect in a shader and I use it with DrawRect, but I would like to convert it to ColorFilter to use it with DrawImage. With shader, as I am using a LUT, I am forced to use Low interpolation (no-mipmap) sampling, instead of Medium (mipmaps) for the drawing image which do not look as great as medium.