.NetCore使用ImageSharp进行图片的生成

   var path = "Image/Mud.png"                                  //图片路径
   FontCollection fonts = new FontCollection();
    FontFamily fontfamily = fonts.Install("Source/SIMHEI.TTF"); //字体的路径     var font  = new Font(fontfamily,50);
    using (Image<Rgba32> image = Image.Load(path))
    {
        image.Mutate(x => x.         DrawText (
                  "陆家嘴旗舰店",           //文字内容
                  font,
                 Rgba32.Black,           //文字颜色
                 new PointF(100,100))    //坐标位置（浮点）
          );
      image.Save(path);
    }

//线上地址的图片，通过获取流的方式读取   
WEBRequest imgRequest = WebRequest.Create(url);
var res = (HttpWebResponse)imgRequest.GetResponse();
var image  = Image.Load(res.GetResponseStream());

 var str = "我是什么长度"； 
  var size = TextMeasurer.Measure(str, new RendererOptions(new Font(fontfamily,50)));
  var width = size.Width;

using SixLabors.ImageSharp;
using SixLabors.ImageSharp.PixelFORMats;
using SixLabors.ImageSharp.Processing;
using SixLabors.Primitives;
using SixLabors.Shapes;
using System;
using System.Collections.Generic;
using System.Text;
namespace CodePicDownload
{
    public static class CupCircularHelper
    {
        public static IImageProcessinGContext<Rgba32> ConvertToAvatar(this IImageProcessingContext<Rgba32> processingContext, Size size, float cornerRadius)
        {
            return processingContext.Resize(new ResizeOptions
            {
                Size = size,
                Mode = ResizeMode.Crop
            }).Apply(i => ApplyRoundedCorners(i, cornerRadius));
        }
        // This method can be seen as an inline implementation of an `IImageProcessor`:
        // (The combination of `IImageOperations.Apply()` + this could be replaced with an `IImageProcessor`)
        private static void ApplyRoundedCorners(Image<Rgba32> img, float cornerRadius)
        {
            IPathCollection corners = BuildCorners(img.Width, img.Height, cornerRadius);
            var graphicOptions = new GraphicsOptions(true)
            {
                AlphaCompositionMode = PixelAlphaCompositionMode.DestOut // enforces that any part of this shape that has color is punched out of the background
            };
            // mutating in here as we already have a cloned original
            // use any color (not Transparent), so the corners will be clipped
            img.Mutate(x => x.Fill(graphicOptions, Rgba32.LimeGreen, corners));
        }
        private static IPathCollection BuildCorners(int imageWidth, int imageHeight, float cornerRadius)
        {
            // first create a square
            var rect = new RectangularPolyGon(-0.5f, -0.5f, cornerRadius, cornerRadius);
            // then cut out of the square a circle so we are left with a corner
            IPath cornerTopLeft = rect.Clip(new EllipsePolygon(cornerRadius - 0.5f, cornerRadius - 0.5f, cornerRadius));
            // corner is now a corner shape positions top left
            //lets make 3 more positioned correctly, we can do that by translating the orgional artound the center of the image
            float rightPos = imageWidth - cornerTopLeft.Bounds.Width + 1;
            float bottomPos = imageHeight - cornerTopLeft.Bounds.Height + 1;
            // move it across the width of the image - the width of the shape
            IPath cornerTopRight = cornerTopLeft.RotateDegree(90).Translate(rightPos, 0);
            IPath cornerBottomLeft = cornerTopLeft.RotateDegree(-90).Translate(0, bottomPos);
            IPath cornerBottomRight = cornerTopLeft.RotateDegree(180).Translate(rightPos, bottomPos);
            return new PathCollection(cornerTopLeft, cornerBottomLeft, cornerTopRight, cornerBottomRight);
        }
  }
}

 using (Image<Rgba32> image = Image.Load("Image/Mud.png"))
 {
     var logoWidth = 300;
     var logo = Image.Load("Image/Logo.png")5     logo.Mutate(x => x.ConvertToAvatar(new Size(logoWidth, logoWidth), logoWidth / 2));  
     image.Mutate(x => x.DrawImage(logo, new Point(100, 100), 1));
     Image.Save("..");
 }

public void WriteToStream(BitMatrix QrMatrix, ImageFormat imageFormat, Stream stream)
        {
            if (imageFormat != ImageFormat.Exif && imageFormat != ImageFormat.Icon && imageFormat != ImageFormat.MemoryBmp)
            {
                DrawingSize size = m_iSize.GetSize(QrMatrix?.Width ?? 21);
                using (Bitmap bitmap = new Bitmap(size.CodeWidth, size.CodeWidth))
                {
                    using (Graphics graphics = Graphics.FromImage(bitmap))
                    {
                        Draw(graphics, QrMatrix);
                        bitmap.Save(stream, imageFormat);
                    }
                }
            }
        }

//Matrix为BitMatrix类型数据，ImageFormat我选择了png类型
MemoryStream ms = new MemoryStream();
WriteToStream(Matrix,System.Drawing.Imaging.ImageFormat.Png, ms);
byte[] data = new byte[ms.Length];
ms.Seek(0, SeekOrigin.Begin);
ms.Read(data, 0, Convert.ToInt32(ms.Length));
var image =  Image.Load(new MemoryStream(data));