csharp 将图像转换为base64

Posted 2021-05-12

using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Linq;

namespace Utils
{
    public static class ImageHelper
    {
        public const string HtmlBase64Format = "data:{0};base64,{1}";

        public static string ToHtmlBase64(this Image img)
        {
            var mimeType = img.GetMimeType();
            var base64 = img.ToBase64();
            return string.Format(HtmlBase64Format, mimeType, base64);
        }

        public static string ToBase64(this Image img)
        {
            using (var ms = new MemoryStream())
            {
                img.Save(ms, img.RawFormat);
                var imageBytes = ms.ToArray();
                return Convert.ToBase64String(imageBytes);
            }
        }

        public static string GetMimeType(this Image img)
        {
            var format = img.RawFormat;
            var codec = ImageCodecInfo.GetImageDecoders().First(c => c.FormatID == format.Guid);
            return codec.MimeType;
        }
    }
}