mvc4 截取上传图片做头像，自动生成不同小尺寸缩略图

很多SNS网站，可以上传头像，微博也是一样，上传的头像经自由裁剪合适后，自动生成多种不同尺寸高质量清晰的，如大中小。

效果如下：

实现：

       页面代码：

<p class="phototxt">选择你要上传的头像</p>
      <div class="upfile">
        @using (Html.BeginForm("uploadHead", "ucenter", FormMethod.Post, new { ID = "user_head_form", enctype = "multipart/form-data" })){
                    <input type="file" name="head" class="filebtn" onchange="$('#user_head_upload_box').hide();$('#user_head_show_box').show();$('#user_head_form').submit();" />
                    <input type="button" class="upimgbtn" value="上传头像" />                        
                }
            </div>

        <div class="sysbtn">
            @using (Html.BeginForm("saveHead", "ucenter", FormMethod.Post, new { ID = "user_head_param_form", enctype = "multipart/form-data" }))
            {
                @Html.HiddenFor(model => model.headFileName, new { id = "head_name" })
                @Html.HiddenFor(model => model.x, new { id = "head_x" })
                @Html.HiddenFor(model => model.y, new { id = "head_y" })
                @Html.HiddenFor(model => model.width, new { id = "head_width" })
                @Html.HiddenFor(model => model.height, new { id = "head_height" })                          
                <input type="submit" class="btnyes" value="保存">
                <input type="button" class="btnno" value="取消" onclick="cancelHead();">
            }
        </div>

section Scripts
{
    <script src="@Url.Content("~/Scripts/jquery-1.7.1.min.js")"></script>
    <script src="@Url.Content("~/Scripts/jquery.form.js")"></script>
    <script src="@Url.Content("~/Scripts/imgareaselect/jquery.imgareaselect.pack.js")"></script>
    <script src="@Url.Content("~/Scripts/head.js")"></script>
    <script src="@Url.Content("~/Scripts/popup.js")"></script>


    <script type="text/javascript">

        $(document).ready(function () {
            $("#user_head_form").ajaxForm({
                success: function (data) {
                    $('#user_head_upload_box').show();
                    $('#user_head_show_box').hide();
                    if (data != undefined && data != null) {
                        if (data.msg == 0) {
                            showreward("<span class="g_error">请上传图片！</span>");
                        } else if (data.msg == -1) {
                            showreward("<span class="g_error">文件格式不对！</span>");
                        } else if (data.msg == -2) {
                            showreward("<span class="g_error">上传图片不能超过10M！</span>");
                        } else if (data.msg == -3) {
                            showreward("<span class="g_error">出现异常，请稍后再试！！</span>");
                        } else {
                            var path = "/avatar/temp/" + data.msg;
                            $("#head_name").val(data.msg);
                            UserHeadUtil.initialize(path);
                           
                        }
                    }
                }
            });
            $("#user_head_param_form").ajaxForm({
                success: function (data) {
                    if (data.msg == 0) {
                        showreward("<span class="g_error">网络出现异常，请稍后再试！</span>");
                    } else if (data.msg == -1) {
                        showreward("<span class="g_error">系统出现异常，请稍后再试！</span>");
                    } else {
                        showreward("<span class="g_ok">修改成功！</span>");
                        $("img#origin_user_head_75").attr("src", "/avatar/75/" + data);
                        $("img#top_user_head_25").attr("src", "/avatar/25/" + data);
                        $('img#user_head_origin').imgAreaSelect({ remove: true });
                        $("#user_head_show_box").hide();
                        $("#user_head_upload_box").show();
                        $("#user_head_origin").attr({
                            "src": "/Content/img/upload.png",
                            "width": "100%",
                            "height": "100%"
                        });
                    }
                }
            });
        });

    </script>
}

后台代码：

        [HttpPost]
        public ActionResult uploadHead(HttpPostedFileBase head)//命名和上传控件name 一样
        {
            try
            {
                if ((head == null))
                {
                    return Json(new { msg = 0 });
                }
                else
                {
                    var supportedTypes = new[] { "jpg", "jpeg", "png", "gif","bmp" };
                    var fileExt = System.IO.Path.GetExtension(head.FileName).Substring(1);
                    if (!supportedTypes.Contains(fileExt))
                    {
                        return Json(new { msg = -1 });
                    }

                    if (head.ContentLength > 1024 * 1000 * 10)
                    {
                        return Json(new { msg = -2 });
                    }

                    Random r = new Random();
                    var filename = DateTime.Now.ToString("yyyyMMddHHmmss") + r.Next(10000) + "." + fileExt;
                    var filepath = Path.Combine(Server.MapPath("~/avatar/temp"), filename);
                    head.SaveAs(filepath);
                    return Json(new { msg = filename });
                }
            }
            catch (Exception)
            {
                return Json(new { msg = -3 });
            }
        }


注意：

  ajaxForm 提交时  ContentType 去掉这些属性就可以了  裸奔才行 不设置 application/json   或者 text/html
 

        [HttpPost]
        [ValidateInput(false)]
        public ActionResult saveHead()
        {
            UploadImageModel model = new UploadImageModel();
            model.headFileName = Request.Form["headFileName"].ToString();
            model.x = Convert.ToInt32(Request.Form["x"]);
            model.y = Convert.ToInt32(Request.Form["y"]);
            model.width = Convert.ToInt32(Request.Form["width"]);
            model.height = Convert.ToInt32(Request.Form["height"]);

            if ((model == null))
            {
                return Json(new { msg = 0 });
            }
            else
            {

                var filepath = Path.Combine(Server.MapPath("~/avatar/temp"), model.headFileName);
                string fileExt = Path.GetExtension(filepath);
                Random r = new Random();
                var filename = DateTime.Now.ToString("yyyyMMddHHmmss") + r.Next(10000) + fileExt;
                var path180 = Path.Combine(Server.MapPath("~/avatar/180"), filename);
                var path75 = Path.Combine(Server.MapPath("~/avatar/75"), filename);
                var path50 = Path.Combine(Server.MapPath("~/avatar/50"), filename);
                var path25 = Path.Combine(Server.MapPath("~/avatar/25"), filename);
                cutAvatar(filepath, model.x, model.y, model.width, model.height, 75L, path180, 180);
                cutAvatar(filepath, model.x, model.y, model.width, model.height, 75L, path75, 75);
                cutAvatar(filepath, model.x, model.y, model.width, model.height, 75L, path50, 50);
                cutAvatar(filepath, model.x, model.y, model.width, model.height, 75L, path25, 25);
                return Json(new { msg = 1 });
            }




        }

        /// <summary>
        /// 创建缩略图
        /// </summary>
        public void cutAvatar(string imgSrc, int x, int y, int width, int height, long Quality, string SavePath, int t)
        {


            Image original = Image.FromFile(imgSrc);

            Bitmap img = new Bitmap(t, t, PixelFormat.Format24bppRgb);

            img.MakeTransparent(img.GetPixel(0, 0));
            img.SetResolution(72, 72);
            using (Graphics gr = Graphics.FromImage(img))
            {
                if (original.RawFormat.Equals(ImageFormat.Jpeg) || original.RawFormat.Equals(ImageFormat.Png)|| original.RawFormat.Equals(ImageFormat.Bmp))
                {
                    gr.Clear(Color.Transparent);
                }
                if (original.RawFormat.Equals(ImageFormat.Gif))
                {
                    gr.Clear(Color.White);
                }


                gr.InterpolationMode = InterpolationMode.HighQualityBicubic;
                gr.SmoothingMode = SmoothingMode.AntiAlias;
                gr.CompositingQuality = CompositingQuality.HighQuality;
                gr.PixelOffsetMode = PixelOffsetMode.HighQuality;
                gr.TextRenderingHint = System.Drawing.Text.TextRenderingHint.ClearTypeGridFit;
                using (var attribute = new System.Drawing.Imaging.ImageAttributes())
                {
                    attribute.SetWrapMode(WrapMode.TileFlipXY);
                    gr.DrawImage(original, new Rectangle(0, 0, t, t), x, y, width, height, GraphicsUnit.Pixel, attribute);
                }
            }
            ImageCodecInfo myImageCodecInfo = GetEncoderInfo("image/jpeg");
            if (original.RawFormat.Equals(ImageFormat.Jpeg))
            {
                myImageCodecInfo = GetEncoderInfo("image/jpeg");
            }
            else
                if (original.RawFormat.Equals(ImageFormat.Png))
                {
                    myImageCodecInfo = GetEncoderInfo("image/png");
                }
                else
                    if (original.RawFormat.Equals(ImageFormat.Gif))
                    {
                        myImageCodecInfo = GetEncoderInfo("image/gif");
                    }else
            if (original.RawFormat.Equals(ImageFormat.Bmp))
            {
                myImageCodecInfo = GetEncoderInfo("image/bmp");
            }

            Encoder myEncoder = Encoder.Quality;
            EncoderParameters myEncoderParameters = new EncoderParameters(1);
            EncoderParameter myEncoderParameter = new EncoderParameter(myEncoder, Quality);
            myEncoderParameters.Param[0] = myEncoderParameter;
            img.Save(SavePath, myImageCodecInfo, myEncoderParameters);
        }

        //根据长宽自适应 按原图比例缩放 
        private static Size GetThumbnailSize(System.Drawing.Image original, int desiredWidth, int desiredHeight)
        {
            var widthScale = (double)desiredWidth / original.Width;
            var heightScale = (double)desiredHeight / original.Height;
            var scale = widthScale < heightScale ? widthScale : heightScale;
            return new Size
            {
                Width = (int)(scale * original.Width),
                Height = (int)(scale * original.Height)
            };
        }
        private static ImageCodecInfo GetEncoderInfo(String mimeType)
        {
            int j;
            ImageCodecInfo[] encoders;
            encoders = ImageCodecInfo.GetImageEncoders();
            for (j = 0; j < encoders.Length; ++j)
            {
                if (encoders[j].MimeType == mimeType)
                    return encoders[j];
            }
            return null;
        }

    }

前端脚本：

//原图/缩略图 的比例 >=1
var UserHeadUtil = {
    ratio: 1,
    view_H:300,
    view_W:300,
    initialize:function(path){
        $("#user_head_origin").attr("src", path);
        $("#user_head_upload_box").hide();
        $("#user_head_show_box").show();
        
        $("#user_head_25").attr("src", path);
        $("#user_head_50").attr("src", path);
        $("#user_head_75").attr("src", path);
        $("#user_head_180").attr("src", path);
        var img = new Image();
        img.src = path;
        if(img.width==0){
            var obj = this;
            img.onload = function(){ 
                obj.imgOperate(img);
            };
        }else{
            this.imgOperate(img);
        }
    },
    imgOperate:function(img){
        if(img){
            this.resize('user_head_origin', img.width, img.height, 300, 300);
            var x=0,y=0,size=0;
            if(this.view_W > this.view_H ){
                x = (this.view_W - this.view_H)/2;
                size = this.view_H;
            }else if(this.view_W < this.view_H){
                y = (this.view_H - this.view_W)/2;
                size = this.view_W;
            }else{
                size = this.view_W;
            }
            var obj = this;
            $('img#user_head_origin').imgAreaSelect({
                aspectRatio:"1:1",
                handles: "corners",
                   persistent:true,
                   show:true,
                imageWidth: obj.view_W,
                imageHeight: obj.view_H,
                x1: x,
                y1: y,
                x2: x + size,
                y2: y + size,
                onSelectChange: function(img, selection){
                    obj.preview('user_head_25', obj.view_W, obj.view_H, selection.x1, selection.y1, selection.width, selection.height, 25, 25);
                    obj.preview('user_head_50', obj.view_W, obj.view_H, selection.x1, selection.y1, selection.width, selection.height, 50, 50);
                    obj.preview('user_head_75', obj.view_W, obj.view_H, selection.x1, selection.y1, selection.width, selection.height, 75, 75);
                    obj.preview('user_head_180', obj.view_W, obj.view_H, selection.x1, selection.y1, selection.width, selection.height, 180, 180);
                    obj.setCutParams(selection.x1, selection.y1, selection.width, selection.height);
                }
            });
            this.preview('user_head_25', this.view_W, this.view_H, x, y, size, size, 25, 25);
            this.preview('user_head_50', this.view_W, this.view_H, x, y, size, size, 50, 50);
            this.preview('user_head_75', this.view_W, this.view_H, x, y, size, size, 75, 75);
            this.preview('user_head_180', this.view_W, this.view_H, x, y, size, size, 180, 180);
            this.setCutParams(x, y, size, size);
        }
    },
    resize:function(id, width, height, limit_W, limit_H){
        if(width>0 && height>0){
            if(width/height >= limit_W/limit_H){
                if(width > limit_W){
                    this.view_W = limit_W;
                    this.view_H = (limit_W/width)*height;
                }
            }else{
                if(height > limit_H){
                    this.view_H = limit_H;
                    this.view_W = (limit_H/height)*width;
                }
            }
            
            $('#'+id).attr( {
                "width" : this.view_W,
                "height" : this.view_H
            });
            
            this.ratio = width / this.view_W;
        }
    },

    preview:function(id, width, height, x, y, cut_W, cut_H, show_W, show_H){
        var scaleX = show_W / (cut_W * this.ratio || 1);
        var scaleY = show_H / (cut_H * this.ratio || 1);
        $('#'+id).css({
             Math.round(scaleX * width * this.ratio) + 'px',
            height: Math.round(scaleY * height * this.ratio) + 'px',
            marginLeft: '-' + Math.round(scaleX * x * this.ratio) + 'px',
            marginTop: '-' + Math.round(scaleY * y * this.ratio) + 'px'
        }); 
    },
    setCutParams:function(x, y, width, height){
        $('#head_x').val(Math.round(x * this.ratio));
        $('#head_y').val(Math.round(y * this.ratio));
        $('#head_width').val(Math.round(width * this.ratio));
        $('#head_height').val(Math.round(height * this.ratio));
    }
};

function cancelHead(){
//    window.location.reload();
    $('img#user_head_origin').imgAreaSelect({ remove: true });
    $("#user_head_show_box").hide();
    $("#user_head_upload_box").show();
    $("#user_head_origin").attr({
        "src": "/Content/img/upload.png",
        "width" : "100%",
        "height" : "100%"
    });
    
    var path = $("img#origin_user_head_75").attr("src"); 
    var index = path.lastIndexOf("/");
    if(index!=-1){
        var name = path.substring(index+1);
        
        $("#user_head_25").attr("src", "/headphone/25/"+name).css({
             25 + 'px',
            height: 25 + 'px',
            marginLeft: 0,
            marginTop: 0
        }); 
        $("#user_head_50").attr("src", "/headphone/50/" + name).css({
             50 + 'px',
            height: 50 + 'px',
            marginLeft: 0,
            marginTop: 0
        }); 
        $("#user_head_75").attr("src", "/headphone/75/" + name).css({
             75 + 'px',
            height: 75 + 'px',
            marginLeft: 0,
            marginTop: 0
        }); 
        $("#user_head_180").attr("src", "/headphone/180/" + name).css({
             180 + 'px',
            height: 180 + 'px',
            marginLeft: 0,
            marginTop: 0
        }); 
    }
}