创建缩略图

来源：互联网发布：cloudzoom.js 编辑：程序博客网时间：2024/06/05 20:29
前段时间，做了一个WPF项目，其中需要做到了图像凭证保存及预览的功能，所以从网上找了些制作缩略图的方法，但是使用时发现会出现严重的内存泄露，往往查看几张大图后就内存不足，特地在已有方法上做了一定修改，解决了内存泄露的问题。
        private void CreateThumbnail1(string[] files, double width, double height)        {            try            {                imageList = null;                imageList = new ObservableCollection<ImageList>();                byte[] bytes;                BitmapImage source = null;                BitmapImage thumbnailSource = null;                System.Drawing.Bitmap sourceBitmap = null;                System.Drawing.Bitmap thumbnailBitmap = null;                MemoryStream ms = null;                for (int i = 0; i < files.Length; i++)                {                    if (!string.IsNullOrEmpty(files[i]))                    {                        string fileName = files[i].Substring(files[i].LastIndexOf("\\") + 1, (files[i].LastIndexOf(".") - files[i].LastIndexOf("\\") - 1));                        string fileType = files[i].Substring(files[i].LastIndexOf(".") + 1, (files[i].Length - files[i].LastIndexOf(".") - 1));                        sourceBitmap = new System.Drawing.Bitmap(files[i]);                        double rw = width / sourceBitmap.Width;                        double rh = height / sourceBitmap.Height;                        double aspect = (double)Math.Min(rw, rh);                        int w = sourceBitmap.Width;                        int h = sourceBitmap.Height;                        if (aspect < 1)                        {                            w = (int)Math.Round(sourceBitmap.Width * aspect);                            h = (int)Math.Round(sourceBitmap.Height * aspect);                        }                        ms = new MemoryStream();                        //原始图                        sourceBitmap.Save(ms, System.Drawing.Imaging.ImageFormat.Bmp);                        bytes = ms.GetBuffer();                        source = new BitmapImage();                        source.BeginInit();                        source.StreamSource = new MemoryStream(bytes);                        source.CacheOption = BitmapCacheOption.OnLoad;                        source.EndInit();                        //缩略图                        thumbnailBitmap = new System.Drawing.Bitmap(sourceBitmap, w, h);                        thumbnailBitmap.Save(ms, System.Drawing.Imaging.ImageFormat.Bmp);                        bytes = ms.GetBuffer();                        thumbnailSource = new BitmapImage();                        thumbnailSource.BeginInit();                        thumbnailSource.StreamSource = new MemoryStream(bytes);                        thumbnailSource.CacheOption = BitmapCacheOption.OnLoad;                        thumbnailSource.EndInit();                        source.Freeze();                        thumbnailSource.Freeze();                        imageList.Add(new ImageList() { Path = files[i], Index = i + 1, SourceImage = source, ThumbnailImage = thumbnailSource, FileName = fileName, FileType = fileType });                        ms.Dispose();                        bytes = null;                        sourceBitmap.Dispose();                        thumbnailBitmap.Dispose();                        source = null;                        thumbnailSource = null;                        sourceBitmap = null;                        thumbnailBitmap = null;                        GC.Collect();                    }                }            }            catch (Exception ex)            {                MessageBox.Show("缩略图转换出错：" + ex.Message);            }        }        private void CreateThumbnail(List<object[]> list)        {            try            {                imageList = null;                imageList = new ObservableCollection<ImageList>();                BitmapImage bi = null;                byte[] data;                for (int i = 0; i < list.Count; i++)                {                    object[] objs = list[i];                    if (objs.Length == 2)                    {                        data = objs[0] as byte[];                        string fullName = objs[1].ToString();                        if (!string.IsNullOrEmpty(fullName))                        {                            string fileName = System.IO.Path.GetFileName(fullName).Split('.')[0];                            string fileType = System.IO.Path.GetFileName(fullName).Split('.')[1];                            bi = new BitmapImage();                            bi.BeginInit();                            bi.StreamSource = new MemoryStream(data);                            bi.CacheOption = BitmapCacheOption.OnLoad;                            bi.EndInit();                            imageList.Add(new ImageList() { Path = fullName, Index = i + 1, ThumbnailImage = bi, FileName = fileName, FileType = fileType });                            bi = null;                        }                    }                }            }            catch (Exception ex)            {                MessageBox.Show("缩略图转换出错：" + ex.Message);            }        }
阅读全文
1 0