wp7蛋疼的90M内存限制,优化图片使用内存(4)[解决]

经过研究我现在解决了 wp7下 超长图片 超过2000长度的图片加载

使用以下技术点

1. 使用 LazyListBox  参考: http://blogs.msdn.com/b/ptorr/archive/2010/10/12/procrastination-ftw-lazylistbox-should-improve-your-scrolling-performance-and-responsiveness.aspx

2.使用 WriteableBitmap 参考:http://www.cnblogs.com/magicboy110/archive/2010/12/13/1905065.html

3.使用 WriteableBitmapEx 参考:http://writeablebitmapex.codeplex.com/

 首先先拆解数据内容

完成图

 代码如下

                    //图片高度
                    double pixelHeight = double.Parse(jobj["height"].ToString());

                    //图片宽度
                    double pixelWidth = double.Parse(jobj["width"].ToString());

                    var uriStr = jobj["img"].ToString();

                    /*********
                     * 计算缩放
                     *********/
                    if (pixelWidth > 400)
                    {
                        pixelHeight = pixelHeight * 400 / pixelWidth;
                    }

                    /***********************************
                     * 
                     *  图片高度大于1000 拆解成 图片列表
                     * 
                     * *********************************/
                    if (pixelHeight > 1000)
                    {
                        WriteableBitmap wb = new WriteableBitmap((int)pixelWidth, (int)pixelHeight);

                        Uri uri = new Uri(uriStr);

                        StreamResourceInfo sri = Application.GetResourceStream(uri);

                        System.Windows.Media.Imaging.Extensions.LoadJpeg(wb, sri.Stream);

                        WriteableBitmap Source;

                        for (int iii = 0; iii * 1000 < pixelHeight; iii++)
                        {
                            LazyListBoxItemVo iivo = new LazyListBoxItemVo();

                            iivo.indexNum = index;

                            if ((iii + 1) * 1000 > pixelHeight)
                            {
                                var h = pixelHeight - (iii * 1000);

                                iivo.imgHeight = h;

                                Source = wb.Crop(0, iii * 1000, 400, h);
                            }
                            else
                            {
                                Source = wb.Crop(0, iii * 1000, 400, 1000);
                            }
                            iivo.imgWidth = pixelWidth;
                            iivo.imgSource = Source;
                            iivo.ContentPanelVisibility = Visibility.Visible;
                            LazyList.Add(iivo);
                        }

                    }//展示原图
                    else
                    {
                     ........................
                    }

　　优化后