Skisharp ColorMatrix Invert black/white

[tinohager]

I try to draw an image and after the first drawing i want invert the color of the drawing.
If the background of my new square is black i need white and if it white i need black.
In my example i draw 3 squares and make a offset of 10 pixel in the x.

Unfortunately, it does not produce the wanted result.

using var skBitmap = new SKBitmap(100, 40);
using var skCanvas = new SKCanvas(skBitmap);
skCanvas.Clear(SKColors.White);

var color = SKColors.Black;
float[] invertMatrix = {
    -1.0f,  0.0f,  0.0f,  0.0f,  255.0f,
    0.0f,  -1.0f,  0.0f,  0.0f,  255.0f,
    0.0f,  0.0f,  -1.0f,  0.0f,  255.0f,
    0.0f,  0.0f,  0.0f,  1.0f,  0.0f
};

using var skPaint = new SKPaint();
skPaint.Color = color;
skPaint.Style = SKPaintStyle.Fill;

skCanvas.DrawRect(10, 10, 20, 20, skPaint);

skPaint.ColorFilter = SKColorFilter.CreateColorMatrix(invertMatrix);

//move +10 in x
skCanvas.DrawRect(20, 10, 20, 20, skPaint);

//move +10 in x
skCanvas.DrawRect(30, 10, 20, 20, skPaint);

[tocsoft]

@tinohager are you sure you have put this in the correct repo?, we have nothing to do with SkiaSharp, ImageSharp is a totally different .net imaging library

[tinohager]

you are absolutely right here I am of course wrong, thanks for the hint