.NetCore生成海报+二维码（logo）_.net core 海报图片 添加二维码

准备工作

引入如下Nuget包依赖

Install-Package QRCoder 1.4.1
Install-Package SixLabors.ImageSharp 1.0.3
Install-Package SixLabors.ImageSharp.Drawing 1.0.0-beta13
或者编辑项目文件，新增如下节点
<PackageReference Include="QRCoder" Version="1.4.1" />
<PackageReference Include="SixLabors.ImageSharp" Version="1.0.3" />
<PackageReference Include="SixLabors.ImageSharp.Drawing" Version="1.0.0-beta13" />
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依赖图片

项目根目录新建字体文件夹（fonts）
Alibaba-PuHuiTi-Regular.ttf
SIMHEI.TTF
新建图片文件夹(images)
bottom.png
mask.png
star.png
top.png

代码如下

        /// <summary>
        /// 生成海报
        /// </summary>
        /// <param name="response">商品海报返回数据</param>
        /// <returns></returns>
        protected async Task<Stream> Generate(ProductResponse response)
        {
            //画布宽度
            int canvasWidth = 327 * 2;
            //画布高度
            int canvasHeight = 485 * 2;

            //卡券图片背景高度
            int CouponImgBgHeight = 197 * 2;

            //卡券图片宽度
            int CouponImgWidth = 260 * 2;

            //卡券图片高度
            int CouponImgHeight = 155 * 2;

            //卡券图片居上间距
            int CouponImgTopPadding = 35 * 2;

            //卡券图片居左间距
            int CouponImgLeftPadding = 33 * 2;

            //卡券图片背景颜色
            Color CouponImgBgColor = Color.ParseHex("#F7F7F7");

            //卡券内容背景高度
            int CouponContentBgHeight = 232 * 2;

            //卡券内容背景颜色
            Color CouponContentBgColor = Color.White;

            //图片的高度
            int imageHeight = 28 * 2;

            //二维码宽度
            int qrCodeWidth = 80 * 2;

            //二维码高度
            int qrCodeHeight = 80 * 2;

            FontCollection fonts = new FontCollection();
            FontFamily numFamily = fonts.Install("fonts/Alibaba-PuHuiTi-Regular.ttf");
            FontFamily textFamily = fonts.Install("fonts/SIMHEI.TTF");

 			// 绘制画布
            using (Image<Rgba32> image = new Image<Rgba32>(canvasWidth, canvasHeight, Color.Transparent))
            {

                //绘制顶部图片
                var topImage = Image.Load("images/top.png");
                image.Mutate(t => t.DrawImage(topImage, new Point(0, 0), 1f));

                //绘制卡券图片背景区域（绘制矩形，四点确定矩形）
                image.Mutate(t => t.FillPolygon(CouponImgBgColor,
                           new Vector2(0, imageHeight),
                           new Vector2(canvasWidth, imageHeight),
                           new Vector2(canvasWidth, CouponImgBgHeight + imageHeight),
                           new Vector2(0, CouponImgBgHeight + imageHeight)));

                //绘制商品图片
                var couponRequest = (HttpWebRequest)WebRequest.Create(response.ImgHttpUrl);
                HttpWebResponse couponResponse = (HttpWebResponse)couponRequest.GetResponse();
                using (Stream responseStream = couponResponse.GetResponseStream())
                {
                    var productImage = Image.Load(responseStream);
                    productImage.Mutate(t => t.Resize(CouponImgWidth, CouponImgHeight));
                    image.Mutate(t => t.DrawImage(productImage, new Point(CouponImgLeftPadding, CouponImgTopPadding), 1f));

                    //绘制圆角蒙版
                    var maskImage = Image.Load("images/mask.png");
                    maskImage.Mutate(t => t.Resize(CouponImgWidth, CouponImgHeight));
                    image.Mutate(t => t.DrawImage(maskImage, new Point(CouponImgLeftPadding, CouponImgTopPadding), 1f));
                }

                //绘制卡券内容背景区域（绘制矩形）
                image.Mutate(t => t.FillPolygon(CouponContentBgColor,
                            new Vector2(0, imageHeight + CouponImgBgHeight),
                            new Vector2(canvasWidth, imageHeight + CouponImgBgHeight),
                            new Vector2(canvasWidth, imageHeight + CouponImgBgHeight + CouponContentBgHeight),
                            new Vector2(0, imageHeight + CouponImgBgHeight + CouponContentBgHeight)));
				// 文字多行显示处理，最多支持两行
                var productName = response.ProductName;
                var offset = 0; // 如果超过一行，则文字下方所有内容偏移的高度
                if (productName.Length > 18)
                {
                    productName = productName.Insert(18, "\r\n");
                    offset += 24;
                }
                if (productName.Length > 38)
                {
                    var length = productName.Length - 37;
                    productName = productName.Remove(37, length) + "...";
                }
                image.Mutate(t => t.DrawText(productName, new Font(textFamily, 16 * 2, FontStyle.Bold), Color.ParseHex("#333333"), new PointF(16 * 2, 242 * 2)));

                image.Mutate(t => t.DrawText("￥", new Font(numFamily, 14 * 2, FontStyle.Bold), Color.ParseHex("#FF0100"), new PointF(16 * 2, 279 * 2 + offset)));
                image.Mutate(t => t.DrawText(response.Amount.ToString(), new Font(numFamily, 24 * 2, FontStyle.Bold), Color.ParseHex("#FF0100"), new PointF(30 * 2, 270 * 2 + offset)));
                // 金额长度过程，金额后面的内容偏移量
                var amountOffset = response.Amount.ToString().Length * 28;
                image.Mutate(t => t.DrawText("优惠券金额", new Font(textFamily, 14 * 2, FontStyle.Bold), Color.ParseHex("#FF0100"), new PointF(30 * 2 + amountOffset, 281 * 2 + offset)));

                //绘制商品类型背景（绘制矩形）
                image.Mutate(t => t.FillPolygon(Color.ParseHex("#FAEFED"),
                            new Vector2(496, 552 + offset),
                            new Vector2(496 + 126, 552 + offset),
                            new Vector2(496 + 126, 552 + 35 + offset),
                            new Vector2(496, 552 + 35 + offset)));

                image.Mutate(t => t.DrawText("类型", new Font(textFamily, 11 * 2, FontStyle.Regular), Color.ParseHex("#FF0100"), new PointF(504 + 20, 558 + offset)));
                //image.Mutate(t => t.DrawText("RMB" + response.ProductFaceValue, new Font(numFamily, 14, FontStyle.Regular), Color.ParseHex("#B0B1B3"), new PointF(160, 278)));
                //image.Mutate(t => t.DrawLines(new Pen(Color.ParseHex("#B0B1B3"),1f), new PointF(155, 288), new PointF(212, 288)));

                var dateText = $"{response.StartDate.Value.ToString("yyyy.MM.dd")}-{response.EndDate.Value.ToString("yyyy.MM.dd")}";
                image.Mutate(t => t.DrawText($"有效期：", new Font(textFamily, 12 * 2, FontStyle.Regular), Color.ParseHex("#666666"), new PointF(16 * 2, 310 * 2 + 5 + offset)));
                image.Mutate(t => t.DrawText(dateText, new Font(numFamily, 12* 2, FontStyle.Regular), Color.ParseHex("#666666"), new PointF(16 * 2 + 90, 310 * 2 + offset)));

                //绘制分割线（绘制直线，两点确定直线）
                image.Mutate(t => t.DrawLines(Pens.Dash(Color.ParseHex("#F3DEDE"), 1f), new PointF(15 * 2, 340 * 2 + offset), new PointF(311 * 2, 340 * 2 + offset)));

                image.Mutate(t => t.DrawText("① 保存图片至相册", new Font(textFamily, 12 * 2, FontStyle.Regular), Color.ParseHex("#B0B1B3"), new PointF(32 * 2, 380 * 2 + offset)));
                image.Mutate(t => t.DrawText("② 长按扫描二维码浏览商品", new Font(textFamily, 12 * 2, FontStyle.Regular), Color.ParseHex("#B0B1B3"), new PointF(32 * 2, 402 * 2 + offset)));

                //绘制二维码，根据产品推广URL生成二维码
                var bitmap = GetQRCode(response.PopularizeUrl, 2);
                using (MemoryStream qrCodeStream = new MemoryStream())
                {
                    bitmap.Save(qrCodeStream, System.Drawing.Imaging.ImageFormat.Jpeg);
                    byte[] data = new byte[qrCodeStream.Length];
                    qrCodeStream.Seek(0, SeekOrigin.Begin);
                    qrCodeStream.Read(data, 0, Convert.ToInt32(qrCodeStream.Length));
                    var qrCodeImage = Image.Load(data);
                    qrCodeImage.Mutate(t => t.Resize(qrCodeWidth, qrCodeHeight));
                    image.Mutate(t => t.DrawImage(qrCodeImage, new Point(215 * 2, 357 * 2 + offset), 1f));
                }

                //绘制底部图片
                var bottomImage = Image.Load("images/bottom.png");
                image.Mutate(t => t.DrawImage(bottomImage, new Point(0, canvasHeight - imageHeight), 1f));
			    // 图片转为文件流
                using (var stream = new MemoryStream())
                {
                    await image.SaveAsync(stream, new PngEncoder());
                    stream.Position = 0; 
                    return stream;
                }
            }

            return null;
        }

        /// <summary>
        /// 获取二维码图片
        /// </summary>
        /// <param name="url">存储内容</param>
        /// <param name="pixel">像素大小</param>
        /// <returns></returns>
        public System.Drawing.Bitmap GetQRCode(string url, int pixel)
        {
            QRCodeGenerator generator = new QRCodeGenerator();
            QRCodeData codeData = generator.CreateQrCode(url, QRCodeGenerator.ECCLevel.Q);
            QRCoder.QRCode qrcode = new QRCoder.QRCode(codeData);
            System.Drawing.Bitmap qrImage = qrcode.GetGraphic(pixel);

            return qrImage;
        }
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效果图

注：图中二维码仅供参考

总结

1. 后端生成图片海报，可能存在性能因素，而且绘制不方便调试，建议前端生成海报
2. 二维码生成官方文档，生成中间带logo的二维码，使用方法
   var bitmap = qrCode.GetGraphic(pixel, Color.Black, Color.White,(Bitmap)Image.FromFile(logoPath), 15, 8);