在.Net MVC上绘制画布或创建图像文件

// 在Controller中的Action方法中生成画布
public ActionResult DrawCanvas()
{
    // 创建画布
    Bitmap bitmap = new Bitmap(500, 500);
    Graphics graphics = Graphics.FromImage(bitmap);

    // 绘制图形
    graphics.FillRectangle(Brushes.Red, 0, 0, 500, 500);
    graphics.DrawEllipse(Pens.Blue, 100, 100, 300, 300);

    // 将画布转换为Base64编码的图片数据
    MemoryStream memoryStream = new MemoryStream();
    bitmap.Save(memoryStream, ImageFormat.Png);
    byte[] imageBytes = memoryStream.ToArray();
    string base64String = Convert.ToBase64String(imageBytes);

    // 将Base64编码的图片数据传递给前端页面
    ViewBag.ImageData = "data:image/png;base64," + base64String;

    return View();
}

<!-- 在View中显示画布 -->
<img src="@ViewBag.ImageData" alt="Canvas Image">

// 在Controller中的Action方法中生成图像文件
public ActionResult CreateImageFile()
{
    // 创建画布
    Bitmap bitmap = new Bitmap(500, 500);
    Graphics graphics = Graphics.FromImage(bitmap);

    // 绘制图形
    graphics.FillRectangle(Brushes.Red, 0, 0, 500, 500);
    graphics.DrawEllipse(Pens.Blue, 100, 100, 300, 300);

    // 保存图像文件
    string filePath = Server.MapPath("~/Images/image.png");
    bitmap.Save(filePath, ImageFormat.Png);

    return Content("Image file created successfully!");
}