PixiEditor/PixiEditor/Helpers/Extensions/PixelFormatHelper.cs

using SkiaSharp;
using System;
using System.Windows.Media;

namespace PixiEditor.Helpers.Extensions
{
    public static class PixelFormatHelper
    {
        public static SKColorType ToSkia(this PixelFormat format, out SKAlphaType alphaType)
        {
            if (TryToSkia(format, out SKColorType color, out alphaType))
            {
                return color;
            }
            else
            {
                throw new NotImplementedException($"Skia does not support the '{format}' format");
            }
        }

        public static bool TryToSkia(this PixelFormat format, out SKColorType colorType, out SKAlphaType alphaType)
        {
            if (format == PixelFormats.Rgba64)
            {
                alphaType = SKAlphaType.Unpremul;
                colorType = SKColorType.Rgba16161616;
                return true;
            }
            else if (format == PixelFormats.Bgra32)
            {
                alphaType = SKAlphaType.Unpremul;
                colorType = SKColorType.Bgra8888;
                return true;
            }
            else if (format == PixelFormats.Default)
            {
                alphaType = SKAlphaType.Unpremul;
                colorType = SKColorType.RgbaF16;
                return true;
            }
            else if (format == PixelFormats.Gray8)
            {
                alphaType = SKAlphaType.Opaque;
                colorType = SKColorType.Gray8;
                return true;
            }
            else if (format == PixelFormats.Pbgra32)
            {
                alphaType = SKAlphaType.Premul;
                colorType = SKColorType.Bgra8888;
                return true;
            }
            else if (format == PixelFormats.Bgr101010 || format == PixelFormats.Bgr24 || format == PixelFormats.Bgr32 || format == PixelFormats.Bgr555 ||
                     format == PixelFormats.Bgr565 || format == PixelFormats.BlackWhite || format == PixelFormats.Cmyk32 || format == PixelFormats.Gray16 ||
                     format == PixelFormats.Gray2 || format == PixelFormats.Gray32Float || format == PixelFormats.Gray4 || format == PixelFormats.Indexed1 ||
                     format == PixelFormats.Indexed2 || format == PixelFormats.Indexed4 || format == PixelFormats.Indexed8 || format == PixelFormats.Prgba128Float ||
                     format == PixelFormats.Prgba64 || format == PixelFormats.Rgb128Float || format == PixelFormats.Rgb24 || format == PixelFormats.Rgb48 ||
                     format == PixelFormats.Rgba128Float)
            {
                alphaType = SKAlphaType.Unknown;
                colorType = SKColorType.Unknown;
                return false;
            }

            throw new NotImplementedException($"'{format}' has not been implemented by {nameof(PixelFormatHelper)}.{nameof(TryToSkia)}()");
        }

        public static bool IsSkiaSupported(this PixelFormat format)
        {
            return TryToSkia(format, out _, out _);
        }
    }
}