按照大小限制等比例压缩图片
需求：
把上图中的img标签中的base64图片转换为图片并压缩为小于100KB
页面布局：
代码：
<div class="layui-form-item"> <div class="layui-inline"> <label class="layui-form-label">未加密密码</label> <div class="layui-input-block"> <input type="text" name="UnEncryptPwd" autocomplete="off" placeholder="请输入密码" class="layui-input" /> </div> </div> <div class="layui-inline"> <button type="button" id="EncryptPwd" class="layui-btn layui-btn-primary">加密</button> <div class="layui-input-block"> <input type="text" name="DecryptPwd" placeholder="" autocomplete="off" class="layui-input" /> </div> </div> </div> <div class="layui-form-item"> <div class="layui-inline"> <label class="layui-form-label">已加密密码</label> <div class="layui-input-block"> <input type="text" name="EncryptPwd" autocomplete="off" placeholder="请输入密码" class="layui-input" /> </div> </div> <div class="layui-inline"> <button type="button" id="DecryptPwd" class="layui-btn layui-btn-primary">解密</button> <div class="layui-input-block"> <input type="text" name="txtDecryptPwd" placeholder="" autocomplete="off" class="layui-input" /> </div> </div> </div> <div class="layui-form-item"> <div class="layui-inline"> <button type="button" id="btnCompress" class="layui-btn layui-btn-primary">上传图片</button> <input type="file" id="input_upload" style="display: none;" accept="image/*" /> <img class="layui-upload-img" id="img_preview" /> <button type="button" id="btn_ckeditor_content" class="layui-btn layui-btn-primary">获取ckeditor内容</button> </div> </div> <div class="layui-form-item"> <div class="layui-inline"> <textarea id="myEditor" name="Content" cols="100" data-sample="1"></textarea> </div> </div
页面初始化完成加载ckeditor的内容
<script type="text/javascript"> $(function () { //CKeditor var ckeditor_object = CKEDITOR.replace('myEditor', { height: '375px', width: '800px', customConfig: '/ckeditor_coustom.js' }); $.post("/Ashx/Upload.ashx", { action: "ReplaceBase64Str2ImgPath" }, function (data) { data = JSON.parse(data); var img_html = data.msg; ckeditor_object.setData(img_html); }); }); </script>
后台响应请求
HttpRequest request; HttpResponse response; public void ProcessRequest(HttpContext context) { request = context.Request; response = context.Response; //允许跨域 context.Response.AddHeader("Access-Control-Allow-Origin", "*"); //允许的请求方式 GET POST DELETE... context.Response.AddHeader("Access-Control-Allow-Methods", "*"); //context.Response.ContentType = "text/plain"; string action = context.Request.Params["action"]; MethodInfo methodinfo = GetType().GetMethod(action); methodinfo.Invoke(this, null); } public void ReplaceBase64Str2ImgPath() { string txt_path = @"G:\zhyue\backup\项目修改-工作日常\2018-08-15 图片等比例压缩 大小小于100k\a.txt"; string txt_html = File.ReadAllText(txt_path); HtmlDocument doc = new HtmlDocument(); doc.LoadHtml(txt_html); //从string获取所有img标签 var img_nodes = doc.DocumentNode.SelectNodes("//img"); if (img_nodes != null && img_nodes.Count > 0) { img_nodes.ToList().ForEach(img_node => { string base64str = img_node.Attributes["src"].Value;//img的src属性 即base64字符串 string relative_savepath= "/upload/img/" + DateTime.Now.ToString("yyyyMM") + "/";//压缩后的图片保存的相对路径 //将base64转换为img图片 并另存为图片 string file_path = Base64Str2Image(relative_savepath,base64str);//压缩后的图片绝对路径 if (File.Exists(file_path)) { //压缩后的图片名称 string compress_img_name = Guid.NewGuid().ToString("N") + Path.GetExtension(file_path); relative_savepath += compress_img_name; //压缩图片到100KB以下 string compress_img_path = Path.GetDirectoryName(file_path) + @"\" + compress_img_name; if (CompressImage(file_path, compress_img_path, 80, 100)) { File.Delete(file_path);//删除原图 保留压缩后的图片 //重写img_node的属性 img_node.Attributes["src"].Value = relative_savepath; } } }); } response.Write("{\"code\":0,\"msg\":\"" + doc.DocumentNode.InnerHtml.Replace("\"","\\\"").Replace("\r\n","").Replace("\n","") + "\"}"); }
base64转图片
/// <summary> /// 将base64字符串转图片 并返回图片保存的绝对路径 /// </summary> /// <param name="relative_savepath">"/upload/img/" + DateTime.Now.ToString("yyyyMM") + "/";</param> /// <param name="base64str"></param> /// <returns></returns> private string Base64Str2Image(string relative_savepath,string base64str) { string file_path = string.Empty; if (base64str.Contains("data:image")) { string[] str_arr = { ";base64," }; string[] base64s = base64str.Split(str_arr, StringSplitOptions.None); string extension = "." + base64s[0].Split('/')[1]; //图片保存路径 //string savePath = "/upload/img/" + DateTime.Now.ToString("yyyyMM") + "/"; //绝对路径 string absolute_path = HttpContext.Current.Server.MapPath(relative_savepath); if (!Directory.Exists(absolute_path)) Directory.CreateDirectory(absolute_path); //文件名称 string fileName = Guid.NewGuid().ToString("N") + extension; //文件保存的绝对路径 file_path = absolute_path + fileName; //将Base64String转为图片并保存 byte[] arr2 = Convert.FromBase64String(base64s[1]); using (MemoryStream ms2 = new MemoryStream(arr2)) { using (Bitmap bmp2 = new Bitmap(ms2)) { bmp2.Save(file_path); } } } return file_path; }
无损压缩图片
/// <summary> /// 无损压缩图片 /// </summary> /// <param name="sFile">原图片地址</param> /// <param name="dFile">压缩后保存图片地址</param> /// <param name="flag">压缩质量（数字越小压缩率越高）1-100</param> /// <param name="size">压缩后图片的最大大小 KB</param> /// <param name="sfsc">是否是第一次调用</param> /// <returns></returns> private bool CompressImage(string sFile, string dFile, int flag = 90, int size = 300, bool sfsc = true) { using (Image iSource = Image.FromFile(sFile)) { ImageFormat tFormat = iSource.RawFormat; //如果是第一次调用，原始图像的大小小于要压缩的大小，则直接复制文件，并且返回true FileInfo firstFileInfo = new FileInfo(sFile); if (sfsc == true && firstFileInfo.Length < size * 1024) { firstFileInfo.CopyTo(dFile); return true; } int dHeight = iSource.Height / 2; int dWidth = iSource.Width / 2; int sW = 0, sH = 0; //按比例缩放 Size tem_size = new Size(iSource.Width, iSource.Height); if (tem_size.Width > dHeight || tem_size.Width > dWidth) { if ((tem_size.Width * dHeight) > (tem_size.Width * dWidth)) { sW = dWidth; sH = (dWidth * tem_size.Height) / tem_size.Width; } else { sH = dHeight; sW = (tem_size.Width * dHeight) / tem_size.Height; } } else { sW = tem_size.Width; sH = tem_size.Height; } using (Bitmap ob = new Bitmap(dWidth, dHeight)) { Graphics g = Graphics.FromImage(ob); g.Clear(Color.WhiteSmoke); g.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality; g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality; g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic; g.DrawImage(iSource, new Rectangle((dWidth - sW) / 2, (dHeight - sH) / 2, sW, sH), 0, 0, iSource.Width, iSource.Height, GraphicsUnit.Pixel); g.Dispose(); //以下代码为保存图片时，设置压缩质量 EncoderParameters ep = new EncoderParameters(); long[] qy = new long[1]; qy[0] = flag;//设置压缩的比例1-100 EncoderParameter eParam = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, qy); ep.Param[0] = eParam; try { ImageCodecInfo[] arrayICI = ImageCodecInfo.GetImageEncoders(); ImageCodecInfo jpegICIinfo = null; for (int x = 0; x < arrayICI.Length; x++) { if (arrayICI[x].FormatDescription.Equals("JPEG")) { jpegICIinfo = arrayICI[x]; break; } } if (jpegICIinfo != null) { ob.Save(dFile, jpegICIinfo, ep);//dFile是压缩后的新路径 FileInfo fi = new FileInfo(dFile); if (fi.Length > 1024 * size) { flag = flag - 10; CompressImage(sFile, dFile, flag, size, false); } } else { ob.Save(dFile, tFormat); } return true; } catch { return false; } } } }
base64替换压缩后的结果：
