从url下载并读取图像

本文关键字：读取 图像 下载 url | 更新日期: 2023-09-27 18:29:37

所以我基本上想做的是从url（png、jpg等）中读取任何类型的图像，并能够获得其纯像素数据。到目前为止，我有这个代码。

  public static async Task<BitmapImage> DownloadImageFromWebsiteAsync(string url)
    {
        try
        {
            HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url);
            using (WebResponse response = await request.GetResponseAsync())
            {
                Stream imageStream = response.GetResponseStream();
                using (var result = new MemoryStream())
                {
                    await imageStream.CopyToAsync(result);
                    byte[] array = result.ToArray();
                    return await ByteArrayToBitmapImage(array);
                }
            }
        }
        catch (WebException ex)
        {
            Debug.WriteLine(ex.Message);
            return null;
        }
    }
    private static async Task<BitmapImage> ByteArrayToBitmapImage(byte[] byteArray)
    {
        var bitmapImage = new BitmapImage();
        var stream = new InMemoryRandomAccessStream();
        await stream.WriteAsync(byteArray.AsBuffer());
        stream.Seek(0);
        bitmapImage.SetSource(stream);
        return bitmapImage;
    }

由于jpeg等编码，将纯byte[]作为像素是不可行的。我想知道他们有没有办法从url下载图像，对其进行解码，并检索像素缓冲区。非常感谢您的帮助。非常感谢。

从url下载并读取图像

试试这个。您需要手动添加using System.Runtime.InteropServices.WindowsRuntime;。

private async Task<byte[]> GetBytesFromImage(string URL)
{
    byte[] srcPixels;
    var uri = new Uri(URL);
    var streamRef = RandomAccessStreamReference.CreateFromUri(uri);
    using (IRandomAccessStreamWithContentType fileStream = await streamRef.OpenReadAsync())
    {
        BitmapDecoder decoder = await BitmapDecoder.CreateAsync(fileStream);
        PixelDataProvider pixelProvider = await decoder.GetPixelDataAsync();
        srcPixels = pixelProvider.DetachPixelData();
    }
    return srcPixels;
}
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