ASP.NET Core SixLabors.ImageSharp 位图图像创建和下载_sixlabors.imagesharp.drawing, version=1.0.0.0, cul-优快云博客

从 MVC 控制器内部创建位图图像并将其发送到浏览器；用 C# 编写并与 Linux 和 Windows 服务器兼容。

使用从 ASP.NET MVC 中的控制器下载任何文件类型File。

此示例创建一个位图 (jpeg) 并将其发送到浏览器。它需要 NuGet 包SixLabors.ImageSharp v1.0.4。

下面的代码将创建以下四幅图像并在它们之间交替显示：

修改后的HomeController.cs文件：

// HomeController.cs
using Microsoft.AspNetCore.Mvc;
using SixLabors.ImageSharp;
using SixLabors.ImageSharp.PixelFormats;

namespace WebApplication1.Controllers
{
   public class HomeController : Controller
   {
       static private byte mod(int x, int y) // NOTE: only returns values 0 to 255
       {
           if ((y & 1) == 0) // NOTE: then base of 2 - no need for division
               return (byte)(x & (y - 1));
           else
               return (byte)(x % y);
       }
       static private void Image0(Image<Rgb24> bmp) // NOTE: this will create a colorful bitmap with colorful stars
       {
           // NOTE: loop through every pixel of the bitmap
           for (int x = 0; x < bmp.Width; x++)
               for (int y = 0; y < bmp.Height; y++)
               {
                   byte p = (byte)(x * y >> 8), c = mod(p, 3), z = 255; // NOTE: "z" can be any shade between 0 and 255
                   bmp[x, y] = new Rgb24(c == 0 ? p : z, c == 1 ? p : z, c == 2 ? p : z); // NOTE: set the color of the pixel at (x, y)
               }
       }
       static private void Image1(Image<Rgb24> bmp) // NOTE: this will create a bitmap with a pattern that repeats
       {
           // NOTE: loop through every pixel of the bitmap
           for (int x = 0; x < bmp.Width; x++)
               for (int y = 0; y < bmp.Height; y++)
               {
                   byte p = mod(x * y, 256), c = mod(p, 3), z = 0; // NOTE: "z" can be any shade between 0 and 255
                   bmp[x, y] = new Rgb24(c == 0 ? p : z, c == 1 ? p : z, c == 2 ? p : z); // NOTE: set the color of the pixel at (x, y)
               }
       }
       static private void Image2(Image<Rgb24> bmp) // NOTE: this will create a bitmap with a unique diagonal pattern
       {
           // NOTE: loop through every pixel of the bitmap
           for (int x = 0; x < bmp.Width; x++)
               for (int y = 0; y < bmp.Height; y++)
               {
                   byte p = mod(x, y), c = mod(p, 3), z = 127; // NOTE: "z" can be any shade between 0 and 255
                   bmp[x, y] = new Rgb24(c == 0 ? p : z, c == 1 ? p : z, c == 2 ? p : z); // NOTE: set the color of the pixel at (x, y)
               }
       }
       static private void Image3(Image<Rgb24> bmp) // NOTE: this will create a bitmap of noise
       {
           var rand = new Random();
           // NOTE: loop through every pixel of the bitmap
           for (int x = 0; x < bmp.Width; x++)
               for (int y = 0; y < bmp.Height; y++)
               {
                   byte p = mod(rand.Next(), 256), c = mod(p, 3), z = 255; // NOTE: "z" can be any shade between 0 and 255
                   bmp[x, y] = new Rgb24(c == 0 ? p : z, c == 1 ? p : z, c == 2 ? p : z); // NOTE: set the color of the pixel at (x, y)
               }
       }
       public IActionResult Index()
       {
           int image = int.Parse(Request.Cookies["image"] ?? "0");
           Response.Cookies.Append("image", (image + 1).ToString());
           const int shift = 9;
           const int width = 1 << shift, height = 1 << shift;
           using (var bmp = new Image<Rgb24>(width, height)) // NOTE: create 24-bit bitmap
           {
               switch (mod(image, 4))
               {
                   case 0:
                       Image0(bmp);
                       break;
                   case 1:
                       Image1(bmp);
                       break;
                   case 2:
                       Image2(bmp);
                       break;
                   case 3:
                       Image3(bmp);
                       break;
               }
               byte[] data;
               using (var ms = new MemoryStream())
               {
                   bmp.SaveAsJpeg(ms); // NOTE: save the bitmap as a JPEG image to the stream
                   data = ms.ToArray();

               }
               // NOTE: alternatively, send the data to the browser as a download with the file name "attachment.jpg" by uncommenting the following line
               // return File(data, System.Net.Mime.MediaTypeNames.Image.Jpeg, "attachment.jpg");

               return File(data, System.Net.Mime.MediaTypeNames.Image.Jpeg); // NOTE: send the data to the browser as a file of mime type "image/jpeg"
           }
       }
   }
}

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