imagemagick 从内存中读取图像 C#

Question

所以我们有一个公共类，它在那里传递名为字符串文件名的图像，我需要将 MaigickImage 与 MemoryStream 或 byte[] 一起使用，因为这是一个网络，文件的地址没有意义。不知何故，我需要将字符串文件名传递给 MemoryStream，然后将其传递给 MagickImage。当我使用 new MagickImage("fileName") 时，它给了我错误，例如找不到文件或目录。所以我需要它通过 MemoryStream 或 byte[] 而不使用 MagickImage("fileName")

        private void Update(ClientFileType type, FileData newFile, int clientId, string fileName)
        {


using (var image = new MagickImage("fileName"))
{
    // Save frame as jpg
    image.Write("fileName");
}

// Write to stream
var settings = new MagickReadSettings();
// Tells the xc: reader the image to create should be 800x600
settings.Width = 800;
settings.Height = 600;

using (var memStream = new MemoryStream())
{
    // Create image that is completely purple and 800x600
    using (var image = new MagickImage("xc:purple", settings))
    {
        // Sets the output format to png
        image.Format = MagickFormat.Png;

        // Write the image to the memorystream
        image.Write(memStream);
    }
}

// Read image from file
using (var image = new MagickImage("fileName"))
{
    // Sets the output format to jpeg
    image.Format = MagickFormat.Jpeg;

    // Create byte array that contains a jpeg file
    byte[] data = image.ToByteArray();
}

            var currentFiles = 
                _clientFileService.Value.GetFilesByClient(clientId).Where(x => x.ClientFileType == type).Select(x => x.Id).ToList();

            _clientFileService.Value.MultipleDelete(currentFiles, null);

            _clientFileService
                .Value
                .AddFile(
                new ClientFile
                {
                    FileName = fileName,
                    Guid = Guid.NewGuid()
                });
        }

Answer 1

这是您想要的模拟实现，请检查它是否对您有帮助。 我只是按照 ImageMagick 文档来弄清楚你必须做什么。由于特定于您的服务实现，我无法进行全面测试。

编辑#1 说明： 我所做的只是创建一个 MemoryStream 并在进行任何处理之前传递给 ImageMagick。我们只访问内存，而不是访问磁盘上的文件。

private void MockUpdate(ClientFileType type, FileData newFile, int clientId, string fileName)
        {
            // Create settings
            var settings = new MagickReadSettings();

            // Let's use 800x600 with format PNG
            settings.Width = 800;
            settings.Height = 600;
            settings.Format = MagickFormat.Png;

            // Buffer where we are saving the result of saving the image
            byte[] imageBuffer = null;

            // Let's create a memory stream
            using (var memStream = new MemoryStream())
            {
                // Pass the memory stream and settings into MagickImage
                using (var image = new MagickImage(memStream, settings))
                {
                    // Write the image to the memorystream
                    image.Write(memStream);

                    // Get the data into the buffer
                    imageBuffer = image.ToByteArray();
                }
            }

            var currentFiles =
                _clientFileService.Value.GetFilesByClient(clientId).Where(x => x.ClientFileType == type).Select(x => x.Id).ToList();

            _clientFileService.Value.MultipleDelete(currentFiles, null);

            _clientFileService
                .Value
                .AddFile(
                new ClientFile
                {
                    FileName = fileName,
                    Guid = Guid.NewGuid(),
                    image = imageBuffer // save the raw data here as a blob
                });
        }

        private byte[] MockProcess(ClientFileType type, int clientId, string fileName)
        {
            // Use service to load buffer with clientId and fileName
            byte[] bufferImage = service.GetImageWithClientId(clientId, fileName);

            // Let's create a memory stream
            using (var memStream = new MemoryStream())
            {
                // Pass the memory stream and settings into MagickImage
                using (var image = new MagickImage(memStream))
                {
                    DoMyProcessing(image);
                }
            }
        }


        private byte[] MockLoadImage(ClientFileType type, int clientId, string fileName)
        {
            // Use service to load buffer with clientId and fileName
            byte[] bufferImage = service.GetImageWithClientId(clientId, fileName);

            return bufferImage;
        }

Answer 2

请查看.NET库上的官方documentation。

截至 2021 年 12 月 27 日，为了举例，以下是有关如何执行此操作的文档示例。希望这有帮助！

// Read from stream.
using (var memStream = LoadMemoryStreamImage())
{
    using (var image = new MagickImage(memStream))
    {
    }
}

// Read from byte array.
var data = LoadImageBytes();
using (var image = new MagickImage(data))
{
}

我建议你这样做：

1. 将文件/内容加载到字节数组中
2. 将字节数组传递到流中
3. 将流传递到 MagicImage 构造函数中。