上传图片添加水印

  由于项目需要，所以写了下面一段添加水印的代码，如下：

后台代码：

 
        ///
        /// 上传图片
        ///
        ///文件
        ///保存的文件夹名称
        [httppost]
        public actionresult uploadingimg(httppostedfilebase upfile, string filepath)
        {
            //判断文件是否存在
            if (upfile == null && upfile.contentlength <= 0)
                return error("文件不正确，请重新上传！");
            var path = appdomain.currentdomain.setupinformation.applicationbase;
            filepath = string.isnullorempty(filepath) ? "unknow" : filepath;
            //返回图片相对地址
            var returnpath = $"{filepath}/{datetime.now.tostring("yyy-mm")}";
            filepath = $"uploadimages\\{filepath}";
            path = $"{path}{filepath}\\{datetime.now.tostring("yyy-mm")}";

            if (!system.io.directory.exists(path))
            {
                system.io.directory.createdirectory(path);//不存在就创建目录
            }
            //验证图片格式是否正确
            string type = upfile.filename.trim().substring(upfile.filename.lastindexof(".") + 1);
            var directory = path;
            path = $"{path}\\{datetime.now.tostring("dd-hh-mm-ss")}.{type}";
            returnpath = $"{returnpath}/{datetime.now.tostring("dd-hh-mm-ss")}water.{type}";
            if (type == "bmp" || type == "jpg" || type == "jpg" || type == "bmp" || type == "png" || type == "png")
            {
                upfile.saveas(path);
                //保存水印图片
                image img = image.fromfile(path);
                addwatermarkandsave(directory, $"{datetime.now.tostring("dd-hh-mm-ss")}water.{type}", "房屋管理", img, color.darkgray);
            }
            else
            {
                return error("文件格式错误!");
            }
            return success(returnpath);
        }

 
        ///
        /// 图片加文字水印
        ///
        ///
        ///水印文字，如果是多行用分号隔开
        ///图片
        ///文字颜色
        ///保存地址
        /// 
        private bool addwatermarkandsave(string path, string filename, string text, image img,
                     color textcolor)
        {
            try
            {
                if (!directory.exists(path))
                {
                    directory.createdirectory(path);
                }
                var paddingleft = 1;
                var paddingtop = 1;
                var textfont = new font("宋体", 19.0f);
                bitmap bm = new bitmap(img);
                system.drawing.graphics graphics = system.drawing.graphics.fromimage(bm);
                system.drawing.brush brush = new solidbrush(textcolor);
                var leftlength = (img.width - paddingleft) / 300;
                leftlength = leftlength == 0 ? 1 : leftlength;
                char[] str = text.tochararray();
                for (var j = 0; j < leftlength; j++)
                {
                    var left = paddingleft + 300 * j;
                    var top = paddingtop + 300 * j;
                    for (int i = 0; i < str.length; i++)
                    {
                        graphics.drawstring(str[i].tostring(), textfont, brush, left + 30 * i, top + 33 * i);
                    }
                }
                graphics.dispose();
                bm.save($"{path}\\{filename}", imageformat.jpeg);
                bm.dispose();
                return true;
            }
            catch (exception e)
            {
            }
            return true;
        }
   
  

 

前端代码示例：

  
<input name="url" type="file" class="upload_input" style="display: none;" onchange="preview(this)">
<div class="preview" id="houseimgtypeherf"></div>
<div class="click" onclick="loadimg(this)"></div>
<div class="delete" onclick="deleteimg(this)">
  <svg class="icon" aria-hidden="true">
     <use xlink:href="#icon-shanchu4"></use>
  </svg>
</div>

 

 

 

 

js代码：注：其中“imghed”为后端传递的图片前缀

function getimgsrc(imgsrc) {
        var formdata = new formdata();
        formdata.append("filepath", "shop");
        formdata.append('upfile', imgsrc);
        var url = "../../common/uploadingimg";
        $.ajax({
            url: url,
            type: 'post',
            data: formdata,
            contenttype: false,
            processdata: false,
            success: function (res) {
                addimgsrc(res.message)
            }, error(err) {
                console.log(err);
            }
        })
    }
    function addimgsrc(src) {
        prevdiv.html('<img src="' + imagehead + '' + src + '"  data-id="' + src + '" alt="图片" />');

    }

  function preview(file) {
    var prevdiv = $(file).parent().find('.preview');
    var id = prevdiv.attr("id");
    var imagehead = $("#imgheadres").val();
    if (file.files && file.files[0]) {
        var reader = new filereader();
        reader.onload = function(evt) {
            var imgsrc = evt.target.result;
            getimgsrc(file.files[0])
        }
        reader.readasdataurl(file.files[0]);
    } else {//ie
    }
    $(file).parent().find('.delete').show();
}