前台Jcrop配合后台Graphics实现图片裁剪并上传

Jcrop：一个功能强大的图片裁剪插件

版本：Jcrop v0.9.12

VS版本：vs2015

下载地址：http://code.ciaoca.com/jquery/jcrop/version/Jcrop-0.9.12.zip

本文主要讲的是，在前台通过file选择图片，然后用Jcrop裁剪好图片后，把偏移量等参数传值到后台，在后台通过Graphics进行图片的截取并上传到服务器，显示一下重点代码

HTML 部分<div class="example">
            <img src="" id="target" alt="[Jcrop Example]"  width="400">
            <div id="preview-pane">
                <div class="preview-container">
                    <img src=""  id="cutImgId"  class="jcrop-preview" alt="Preview">
                </div>
            </div>
        </div>

//脚本$(function () {
        var api = frameElement.api, W = api.opener;
       //获取原图片实际的宽高
        var img = new Image();
        img.src = W.document.getElementById(‘ImageCropUrl‘).value;
        img.onload = function () {
            imgweight = img.width;
            imgheight = img.height
        };
        var    boundx,
            boundy,
            // Grab some information about the preview pane
            $preview = $(‘#preview-pane‘),
            $pcnt = $(‘#preview-pane .preview-container‘),
            $pimg = $(‘#preview-pane .preview-container img‘),
            xsize = $pcnt.width(),
            ysize = $pcnt.height();
        console.log(‘init‘, [xsize, ysize]);
        $(‘#target‘).Jcrop({
            onChange: updatePreview,
            onSelect: updatePreview,
            aspectRatio: 2
            //setSelect: [20, 300, 66, 68]
        }, function () {
            var bounds = this.getBounds();
            boundx = bounds[0];
            boundy = bounds[1];
            jcrop_api = this;
            $preview.appendTo(jcrop_api.ui.holder);
        }
        );

//传递到后台

    function saveUploadImg(){

        c = jcrop_api.tellSelect();

        if (parseInt(c.w) > 0) {

            $.ajax({

                  url:‘/cartoon-web/contentAffix/cutimageAndSaveAffix‘,
                  //x和y 是坐标，w和h是宽高
                  data :{"x":Math.round(c.x * imgweight / 280),"y":Math.round(c.y * imgheight / 350),"w":Math.round(c.w * imgweight / 280),"h":Math.round(c.h * imgheight / 350),"filename":filename,"fileid":fileid,"originalfilename":originalfilename},

                  dataType:‘json‘,

                  success: function(data){

                     if(data.result == "success"){

                     }else{

                         alert("请选择图片");

                     }

                  }

            });

        } 

    }

//后台代码if (uploadFile != null)
                {
                    Bitmap bmpBase = new Bitmap(uploadFile.InputStream);
                    Bitmap bmpNew = new Bitmap(w,h);
                    var format = bmpBase.PixelFormat; bmpBase.PixelFormat);
                    using (Graphics g = Graphics.FromImage(bmpNew))
                    {
                        // 用白色清空
                        g.Clear(Color.White);
                        // 指定高质量的双三次插值法。执行预筛选以确保高质量的收缩。此模式可产生质量最高的转换图像。
                        g.InterpolationMode = InterpolationMode.HighQualityBicubic;
                        // 指定高质量、低速度呈现。
                        g.SmoothingMode = SmoothingMode.HighQuality;
                        // 在指定位置并且按指定大小绘制指定的 Image 的指定部分。
                        g.DrawImage(bmpBase, 0, 0, new Rectangle(x, y, w, h), GraphicsUnit.Pixel);
                        Bitmap s = Bitmap.FromHbitmap(bmpNew.GetHbitmap());

                        MemoryStream stream = new MemoryStream();
                        //获取裁剪后图片的文件流
                        bmpNew.Save(stream, ImageFormat.Jpeg);
                        bmpBase.Dispose();
                        bmpNew.Dispose();
                        stream.Dispose();
                        return Content(url);
                    }

                }