Avalonia/tests/Avalonia.Base.UnitTests/Media/Imaging/PixelFormatTranscoderTests.cs

using Avalonia.Media.Imaging;
using Avalonia.Platform;
using Xunit;

namespace Avalonia.Base.UnitTests.Media.Imaging
{
    public class PixelFormatTranscoderTests
    {
        [Fact]
        public void Should_Transcode()
        {
            var sourceMemory = CreateBitmapMemory();

            var destMemory = new BitmapMemory(PixelFormat.Bgra8888, AlphaFormat.Opaque, sourceMemory.Size);

            PixelFormatTranscoder.Transcode(
                sourceMemory.Address,
                sourceMemory.Size,
                sourceMemory.RowBytes,
                sourceMemory.Format,
                sourceMemory.AlphaFormat,
                destMemory.Address,
                destMemory.RowBytes,
                destMemory.Format,
                destMemory.AlphaFormat);

            var reader = new PixelFormatReader.Bgra8888PixelFormatReader();

            reader.Reset(destMemory.Address);

            Assert.Equal(new Rgba8888Pixel(255, 0, 0, 0), reader.ReadNext());
            Assert.Equal(new Rgba8888Pixel(0, 255, 0, 0), reader.ReadNext());
            Assert.Equal(new Rgba8888Pixel(0, 0, 255, 0), reader.ReadNext());
        }

        private BitmapMemory CreateBitmapMemory()
        {
            var bitmapMemory = new BitmapMemory(PixelFormat.Rgba8888, AlphaFormat.Opaque, new PixelSize(3, 1));

            var sourceWriter = new PixelFormatWriter.Rgba8888PixelFormatWriter();

            sourceWriter.Reset(bitmapMemory.Address);

            sourceWriter.WriteNext(new Rgba8888Pixel { R = 255 });
            sourceWriter.WriteNext(new Rgba8888Pixel { G = 255 });
            sourceWriter.WriteNext(new Rgba8888Pixel { B = 255 });

            return bitmapMemory;
        }
    }
}