ImageSharp库使用ProcessPixelRows方法，貌似效率没有提高很多，还不如bitmap,写错?

ilovecomputer66

如果普通用for循环，用imageSharp的索引进行处理。测试图需要800毫秒。 用上ProcessPixelRows，只降低到平均720毫秒
而用bitmap.lock，然后用unsafe的byte*操作，只有125毫秒。 span是C#比较新版本，封装的对指针安全使用，效率与原生使用unsafe指针，看网上文章基本差不多。但为什么imageSharp ProcessPixelRows效率如此低？
我感觉应该代码写错了，但这就是照着官方demo写的，也没看出哪写的不对，请大佬指点了
如果普通用for循环，用imageSharp的索引进行处理

[C#] 纯文本查看 复制代码

SixLabors.ImageSharp.Image<Rgba32> oriImage = SixLabors.ImageSharp.Image.Load<Rgba32>(config.OriPicPath);
                    SixLabors.ImageSharp.Image<Rgba32> resultImage = SixLabors.ImageSharp.Image.Load<Rgba32>(config.ResultPicPath);
                    int width = oriImage.Width;
                    int height = oriImage.Height;

                    Rgba32 oriPixel;
                    Rgba32 resultPixel;

                    for (int x = 0; x < width; x++)
                    {
                        for (int y = 0; y < height; y++)
                        {
                            resultPixel = resultImage[x, y];
                            if (resultPixel.A > 0)
                            {
                                oriPixel = oriImage[x, y];
                                resultImage[x, y] = new Rgba32(oriPixel.R, oriPixel.G, oriPixel.B, resultPixel.A);
                            }
                        }
                    }

                    string newFilePath = Path.Combine(Path.GetDirectoryName(config.OriPicPath), Path.GetFileNameWithoutExtension(config.OriPicPath) + "_do" + Path.GetExtension(config.ResultPicPath));
                    FileStream fileStream = new FileStream(newFilePath, FileMode.Create);
                    PngEncoder pngEncoder = new PngEncoder();
                    resultImage.Save(fileStream, pngEncoder);
                    fileStream.Close();

然后是用上ProcessPixelRows

[C#] 纯文本查看 复制代码

SixLabors.ImageSharp.Image<Rgba32> oriImage = SixLabors.ImageSharp.Image.Load<Rgba32>(config.OriPicPath);
                    SixLabors.ImageSharp.Image<Rgba32> resultImage = SixLabors.ImageSharp.Image.Load<Rgba32>(config.ResultPicPath);
                    int width = oriImage.Width;
                    int height = oriImage.Height;

                    resultImage.ProcessPixelRows(oriImage, (resultAccessor, oriAccessor) =>
                    {
                        for (int y = 0; y < height; y++)
                        {
                            Span<Rgba32> resultRow = resultAccessor.GetRowSpan(y);
                            Span<Rgba32> oriRow = oriAccessor.GetRowSpan(y);

                            for (int x = 0; x < width; x++)
                            {
                                ref Rgba32 resutPixel = ref resultRow[x];
                                if (resutPixel.A > 0)
                                {
                                    ref Rgba32 oriPixel = ref oriRow[x];
                                    resutPixel = new Rgba32(oriPixel.R, oriPixel.G, oriPixel.B, resutPixel.A);
                                }
                            }
                        }
                    });

                    string newFilePath = Path.Combine(Path.GetDirectoryName(config.OriPicPath), Path.GetFileNameWithoutExtension(config.OriPicPath) + "_do" + Path.GetExtension(config.ResultPicPath));
                    FileStream fileStream = new FileStream(newFilePath, FileMode.Create);
                    PngEncoder pngEncoder = new PngEncoder();
                    resultImage.Save(fileStream, pngEncoder);
                    fileStream.Close();