图片压缩之处理小图片压缩策略

Posted 2020-09-16 wgwyanfs

在进行图片压缩的时候。有时候会碰到要压缩的图片尺寸小于指定的压缩尺寸，若直接压缩会导致图片失真。

当然。最好的方式是挑选合适尺寸图片进行上传。

这里给出的方法是：对不足尺寸部分进行空白填充。

详细參见下面代码

using System;
using System.Drawing.Drawing2D;
using System.Drawing;
using System.IO;
using System.Drawing.Imaging;

namespace CommonLib
{
    public class ImageUtils
    {

        /// <summary>
        /// 创建缩略图像,缩略图是一个正方型的小图片
        /// </summary>
        /// <param name="thumbnilWidth">缩略图的宽度</param>
        /// <param name="inputFileName">原始图像文件名称</param>
        /// <param name="outputFileName">输出的所略图文件名称</param>
        public static void Thumbnil(int thumbnilWidth, string inputFileName, string outputFileName)
        {

            Image src = Image.FromFile(inputFileName);
            Image pThumbnail = Thumbnil(thumbnilWidth, src);
            pThumbnail.Save(outputFileName);
        }

        public static void Thumbnil(int thumbnilWidth, string inputFileName, string outputFileName, ImageFormat format)
        {

            Image src = Image.FromFile(inputFileName);
            Image pThumbnail = Thumbnil(thumbnilWidth, src);
            SaveImage(outputFileName, format, pThumbnail, (long)98);

        }

        /// <summary>
        /// 创建缩略图像,缩略图是一个正方型的小图片
        /// </summary>
        /// <param name="thumbnilWidth"></param>
        /// <param name="inputStream"></param>
        /// <param name="outputFileName"></param>
        /// <param name="format"></param>
        public static void Thumbnil(int thumbnilWidth, Stream inputStream, string outputFileName, ImageFormat format)
        {
            Image src = Image.FromStream(inputStream);
            Image pThumbnail = Thumbnil(thumbnilWidth, src);
            SaveImage(outputFileName, format, pThumbnail, (long)98);
        }

        /// <summary>
        /// 创建缩略图像,缩略图是一个正方型的小图片
        /// </summary>
        /// <param name="thumbnilWidth"></param>
        /// <param name="inputStream"></param>
        /// <param name="outputFileName"></param>
        public static void Thumbnil(int thumbnilWidth, Stream inputStream, string outputFileName)
        {
            Image src = Image.FromStream(inputStream);
            Image pThumbnail = Thumbnil(thumbnilWidth, src);
            pThumbnail.Save(outputFileName);
            src.Dispose();
            pThumbnail.Dispose();
        }

        /// <summary>
        /// 缩略图
        /// </summary>
        /// <param name="maxWidth">最大宽度</param>
        /// <param name="maxHeight">最大的高度</param>
        /// <param name="inputStream">图片流</param>
        /// <param name="outputFileName">输出路径</param>
        public static void Thumbnil(int maxWidth, int maxHeight, Stream inputStream, string outputFileName)
        {
            string fileDirectory = Path.GetDirectoryName(outputFileName);
            if (!Directory.Exists(fileDirectory))
            {
                DirectoryInfo di = Directory.CreateDirectory(fileDirectory);//创建一个文件
            }
            System.Drawing.Image img = System.Drawing.Image.FromStream(inputStream);
            if (img.Width > maxWidth || img.Height > maxHeight)
            {
                int pwidth = 0;
                if (img.Height / maxHeight > img.Width / maxWidth)
                {
                    pwidth = Convert.ToInt16(((decimal)img.Width) * maxHeight / img.Height);
                }
                else
                {
                    pwidth = maxWidth;
                }
                Thumbnil(pwidth, inputStream, outputFileName);
            }
            else
            {
                Thumbnil(img.Width, inputStream, outputFileName);
            }
            img.Dispose();
        }

        public static void Thumbnil(int thumbnilWidth, Stream inputStream, Stream outputStream, ImageFormat format)
        {
            Image src = Image.FromStream(inputStream);
            Image pThumbnail = Thumbnil(thumbnilWidth, src);
            SaveImage(outputStream, format, pThumbnail, (long)98);
        }

        public static Image Thumbnil(int thumbnilWidth, Image src)
        {
            int width_heigh = src.Width;
            if (src.Height < src.Width)
                width_heigh = src.Height;

            RectangleF sourceRect = new RectangleF((src.Width - width_heigh) / 2,
                (src.Height - width_heigh) / 2, width_heigh, width_heigh);

            RectangleF destinationRect = new RectangleF(0, 0, thumbnilWidth, thumbnilWidth);
            Image pThumbnail = new Bitmap(thumbnilWidth, thumbnilWidth);
            Graphics g = Graphics.FromImage(pThumbnail);
            g.InterpolationMode = InterpolationMode.High;
            g.DrawImage(src, destinationRect, sourceRect, GraphicsUnit.Pixel);
            return pThumbnail;
        }

        private static void SaveImage(string outputFileName, ImageFormat format, Image image)
        {
            SaveImage(outputFileName, format, image, (long)95);
        }

        private static void SaveImage(string outputFileName, ImageFormat format, Image image, long qualityValue)
        {
            if (format == ImageFormat.Jpeg)
            {
                EncoderParameters ep = new EncoderParameters();
                ep.Param[0] = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, qualityValue);

                ImageCodecInfo ici = null;
                ImageCodecInfo[] codecs = ImageCodecInfo.GetImageEncoders();
                foreach (ImageCodecInfo codec in codecs)
                {
                    if (codec.MimeType == "image/jpeg")
                    {
                        ici = codec;
                        break;
                    }
                }

                if (ici != null)
                    image.Save(outputFileName, ici, ep);
                else
                    image.Save(outputFileName, format);
            }
            else
                image.Save(outputFileName, format);
        }

        private static void SaveImage(Stream outputStream, ImageFormat format, Image image)
        {
            SaveImage(outputStream, format, image, (long)95);
        }

        private static void SaveImage(Stream outputStream, ImageFormat format, Image image, long qualityValue)
        {
            if (format == ImageFormat.Jpeg)
            {
                EncoderParameters ep = new EncoderParameters();
                ep.Param[0] = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, qualityValue);

                ImageCodecInfo ici = null;
                ImageCodecInfo[] codecs = ImageCodecInfo.GetImageEncoders();
                foreach (ImageCodecInfo codec in codecs)
                {
                    if (codec.MimeType == "image/jpeg")
                    {
                        ici = codec;
                        break;
                    }
                }

                if (ici != null)
                    image.Save(outputStream, ici, ep);
                else
                    image.Save(outputStream, format);
            }
            else
                image.Save(outputStream, format);
        }

        /// <summary>
        /// 按图片原始比例创建缩略图像
        /// </summary>
        public static void ScaleImage(int maxPixel, string inputFileName, string outputFileName, string waterMarkText, InterpolationMode interpolationMode, ImageFormat imageFormat)
        {
            Image src = Image.FromFile(inputFileName);
            int src_height = src.Height;
            int src_width = src.Width;
            int destW = maxPixel;
            int destH = maxPixel;

            double wh_Ratio = src_width * 1.0 / src_height * 1.0;

            if (src_height <= maxPixel && src_width <= maxPixel)
            {
                File.Copy(inputFileName, outputFileName);
                src.Dispose();
                return;
            }
            else if (wh_Ratio <= 1)
            {
                destW = (int)Math.Round(destH * wh_Ratio);
                if (destW == 0)
                    destW = 1;
            }
            else if (wh_Ratio > 1)
            {
                destH = (int)Math.Round(destW / wh_Ratio);
                if (destH == 0)
                    destH = 1;
            }

            RectangleF sourceRect = new RectangleF(0, 0, src_width, src_height);
            RectangleF destinationRect = new RectangleF(0, 0, destW, destH);

            Image destImg = new Bitmap(destW, destH);

            Graphics g = Graphics.FromImage(destImg);

            if (interpolationMode == InterpolationMode.Bilinear)
                interpolationMode = InterpolationMode.High;

            g.InterpolationMode = interpolationMode;
            g.DrawImage(src, destinationRect, sourceRect, GraphicsUnit.Pixel);

            #region 增加水印的算法
            //WaterMark(destImg, GetWaterMarkImage());
            WaterMarkText(destImg, waterMarkText);
            #endregion

            long qulityValue = 95;
            if (destW < 200 || destH < 200)
                qulityValue = 98;

            //destImg.Save(outputFileName, imageFormat);
            SaveImage(outputFileName, imageFormat, destImg, qulityValue);

            destImg.Dispose();
            src.Dispose();
            g.Dispose();
            return;
        }

        /// <summary>
        /// 按图片原始比例创建缩略图像
        /// </summary>
        public static void ScaleImage(int maxPixel, Stream inputStream, string outputFileName, string waterMarkText, InterpolationMode interpolationMode, ImageFormat imageFormat)
        {
            Image src = Image.FromStream(inputStream);
            int src_height = src.Height;
            int src_width = src.Width;
            int destW = maxPixel;
            int destH = maxPixel;

            double wh_Ratio = src_width * 1.0 / src_height * 1.0;

            if (src_height <= maxPixel && src_width <= maxPixel)
            {
                src.Save(outputFileName, imageFormat);
                src.Dispose();
                return;
            }
            else if (wh_Ratio <= 1)
            {
                destW = (int)Math.Round(destH * wh_Ratio);
            }
            else if (wh_Ratio > 1)
            {
                destH = (int)Math.Round(destW / wh_Ratio);
            }

            RectangleF sourceRect = new RectangleF(0, 0, src_width, src_height);
            RectangleF destinationRect = new RectangleF(0, 0, destW, destH);

            Image destImg = new Bitmap(destW, destH);

            Graphics g = Graphics.FromImage(destImg);

            if (interpolationMode == InterpolationMode.Bilinear)
                interpolationMode = InterpolationMode.High;

            g.InterpolationMode = interpolationMode;
            g.DrawImage(src, destinationRect, sourceRect, GraphicsUnit.Pixel);

            #region 增加水印的算法
            //WaterMark(destImg, GetWaterMarkImage());
            WaterMarkText(destImg, waterMarkText);
            #endregion

            //默认处理。大图片就减少一些画质
            long qulityValue = 95;
            if (destW < 200 || destH < 200)
                qulityValue = 98;
            //destImg.Save(outputFileName, imageFormat);
            SaveImage(outputFileName, imageFormat, destImg, qulityValue);

            destImg.Dispose();
            src.Dispose();
            g.Dispose();
            return;
        }

        /// <summary>
        /// 图片压缩
        /// </summary>
        /// <param name="maxWidth">最大宽度</param>
        /// <param name="maxHeight">最大高度</param>
        /// <param name="inputStream">图片流</param>
        /// <param name="outputFileName">输出路径</param>
        /// <param name="waterMarkText">水印文字</param>
        /// <param name="interpolationMode">生成格式</param>
        /// <param name="imageFormat">图片格式化</param>
        public static void ScaleImage(int maxWidth, int maxHeight, Stream inputStream, string outputFileName, string waterMarkText, InterpolationMode interpolationMode, ImageFormat imageFormat)
        {
            string fileDirectory = Path.GetDirectoryName(outputFileName);
            if (!Directory.Exists(fileDirectory))
            {
                DirectoryInfo di = Directory.CreateDirectory(fileDirectory);//创建一个文件
            }
            System.Drawing.Image img = System.Drawing.Image.FromStream(inputStream);
            if (img.Width > 770 || img.Height > 560)
            {
                int pwidth = 0;
                if (img.Height / maxHeight > img.Width / maxWidth)
                {
                    pwidth = Convert.ToInt16(((decimal)img.Width) * maxHeight / img.Height);
                }
                else
                {
                    pwidth = maxWidth;
                }
                ScaleImage(pwidth, inputStream, outputFileName, waterMarkText, interpolationMode, imageFormat);
            }
            else
            {
                ScaleImage(img.Width, inputStream, outputFileName, waterMarkText, interpolationMode, imageFormat);
            }
            img.Dispose();
        }

        public static void WaterMarkText(Image srcImg, string waterMarkText)
        {
            try
            {
                if (string.IsNullOrEmpty(waterMarkText))
                    return;

                if (srcImg.Width <= 100)
                    return;

                int waterMarkWidth = srcImg.Width;
                int waterMarkHeight = 20; //px;

                WaterMarkText(srcImg, waterMarkText, 0, srcImg.Height - waterMarkHeight, waterMarkHeight, waterMarkWidth, new Font("微软雅黑", 12, GraphicsUnit.Pixel));
            }
            catch
            {
                throw;
            }

        }


        public static void WaterMarkText(Image srcImg, string waterMarkText, int left, int top, int waterMarkHeight, int waterMarkWidth, Font font)
        {
            try
            {

                Graphics g = Graphics.FromImage(srcImg);

                Rectangle rect = new Rectangle(left, top, waterMarkWidth, waterMarkHeight);

                //画半透明确色底色
                Brush brush = new SolidBrush(Color.FromArgb(99, Color.White));
                g.FillRectangle(brush, rect);

                //画文字
                rect.Width = rect.Width - 10;
                rect.Y = rect.Y + 2;
                g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
                StringFormat sf = new StringFormat();
                sf.Alignment = StringAlignment.Far;
                g.DrawString(waterMarkText, font, Brushes.Black, rect, sf);

                //存盘
                g.Save();
                #region 释放此函数创建的GDI+资源
                brush.Dispose();
                font.Dispose();
                sf.Dispose();

                g.Dispose();
                #endregion
            }
            catch
            {
                throw;
            }

        }

        private static void WaterMark(Image srcImg, Image waterMarkImage)
        {
            if (waterMarkImage == null)
                return;

            if (waterMarkImage.Width > (srcImg.Width - 20))
                return;

            if (waterMarkImage.Height > (srcImg.Height - 20))
                return;

            //水印在右下角。距离边6px位置
            Rectangle rect = new Rectangle(0, 0, waterMarkImage.Width, waterMarkImage.Height);

            #region 生成一个暂时Image
            Image tempImage = new Bitmap(waterMarkImage.Width, waterMarkImage.Height);

            float[][] ptsArray ={ 
				new float[] {1, 0, 0, 0, 0},
				new float[] {0, 1, 0, 0, 0},
				new float[] {0, 0, 1, 0, 0},
				new float[] {0, 0, 0, 0.5f, 0}, //注意：此处为0.5f，图像为半透明
				new float[] {0, 0, 0, 0, 1}};

            ColorMatrix clrMatrix = new ColorMatrix(ptsArray);
            Graphics tempGraphics = Graphics.FromImage(tempImage);

            //将原图的要被水印覆盖的位置copy到暂时Image
            Rectangle srcRect = new Rectangle(srcImg.Width - waterMarkImage.Width - 6, srcImg.Height - waterMarkImage.Height - 6,
                waterMarkImage.Width, waterMarkImage.Height);

            tempGraphics.DrawImage(srcImg, rect, srcRect, GraphicsUnit.Pixel);

            ImageAttributes tempImgAttributes = new ImageAttributes();
            tempImgAttributes.SetColorMatrix(clrMatrix, ColorMatrixFlag.SkipGrays, ColorAdjustType.Bitmap);

            //将水印图片贴到暂时区，跳过gray颜色。
 白色也是一种gray。将是透明色
            tempGraphics.DrawImage(waterMarkImage, rect, 0, 0, waterMarkImage.Width, waterMarkImage.Height,
                GraphicsUnit.Pixel, tempImgAttributes);

            tempGraphics.Save();
            #endregion

            #region 将暂时Image以透明贴图的方式绘至原图

            ImageAttributes imgAttributes = new ImageAttributes();
            imgAttributes.SetColorKey(Color.White, Color.White);

            //绘图像
            Graphics g = Graphics.FromImage(srcImg);

            //srcRect 是原图要覆盖的区域，此时作为目标区域
            g.DrawImage(tempImage, srcRect, 0, 0, tempImage.Width, tempImage.Height,
                GraphicsUnit.Pixel, imgAttributes);
            g.Save();

            #endregion

            #region 释放此函数创建的资源
            g.Dispose();

            tempGraphics.Dispose();
            tempImage.Dispose();
            #endregion
        }

        private static Image waterMarkImage = null;

        public static Image GetWaterMarkImage()
        {
            return waterMarkImage;
        }

        public static void SetWaterMarkImage(Image image)
        {
            waterMarkImage = image;
        }
    }


    /// <summary>
    /// 图片处理:缩略图片
    /// </summary>
    public class ImageDealLib
    {
        /// <summary>
        /// 图片保存类型
        /// JPEG:.jpg格式;
        /// GIF:.gif格式;
        /// PNG:.png格式;
        /// </summary>
        public enum ImageType
        {
            JPEG,
            GIF,
            PNG
        }

        /// <summary>
        /// 水印模式
        /// Center:中间;
        /// CenterUp:中上;
        /// CenterDown:中下;
        /// LeftUp:左上;
        /// LeftDown:左下;
        /// RightUp:右上;
        /// RightDown:右下;
        /// Random:随机;
        /// </summary>
        public enum WaterType
        {
            Center,
            CenterUp,
            CenterDown,
            LeftUp,
            LeftDown,
            RightUp,
            RightDown,
            Random
        }

        /// <summary>
        /// 缩略模式
        /// X--按宽度缩放,高着宽比例;
        /// Y--按高度缩放,宽着宽比例;
        /// XY--按给定mwidth,mheight(此模式mwidth,mheight为必须值)进行缩略;
        /// </summary>
        public enum ResizeType
        {
            X,
            Y,
            XY
        }

        /// <summary>
        /// 文件检測模式
        /// M:不检測文件是否存在,返回ServerMapPath;
        /// C:检測文件是否存在,返回ServerMapPath;
        /// </summary>
        public enum FileCheckModel
        {
            M,
            C
        }

        /// <summary>
        /// 原图文件是否保存
        /// Delete:保存
        /// Save:不保存,删除
        /// </summary>
        public enum FileCache
        {
            Save,
            Delete
        }

        /// <summary>
        /// 依据指定：缩略宽、高,缩略图片并保存
        /// 返回图片虚拟路径,和一个警告信息,可依据此信息获取图片合成信息
        /// </summary>
        /// <param name="picpath">原图路径</param>
        /// <param name="model">缩略模式[X,Y,XY](默认XY模式)</param>
        /// <param name="spath">文件保存路径(默认跟路径)</param>
        /// <param name="imgtype">图片保存类型</param>
        /// <param name="mwidth">缩略宽度(默认原图高度)</param>
        /// <param name="mheight">缩略高度(默认原图高度)</param>
        /// <param name="filecache">原文件处理方式</param>
        /// <param name="warning">处理警告信息</param>
        /// <returns>错误,返回错误信息;成功,返回图片路径</returns>

        public static string Resizepic(double? mwidth, double?
 mheight, string picpath, string spath, ResizeType model, ImageType imgtype, FileCache filecache, out string warning)
        {
            //反馈信息
            System.Text.StringBuilder checkmessage = new System.Text.StringBuilder();
            //原图路径
            if (string.IsNullOrWhiteSpace(picpath))
            {
                checkmessage.Append("请输入原图路径。");
                warning = checkmessage.ToString().TrimEnd(‘;‘);
                return string.Empty;
            }

            //文件保存路径
            if (string.IsNullOrWhiteSpace(spath))
            {
                checkmessage.Append("请输入保存路径。");
                warning = checkmessage.ToString().TrimEnd(‘;‘);
                return string.Empty;
            }
            else
            {
                string fileDirectory = Path.GetDirectoryName(spath);
                if (!Directory.Exists(fileDirectory))
                {
                    DirectoryInfo di = Directory.CreateDirectory(fileDirectory);//创建一个文件
                }
            }

            //缩略宽度
            double swidth = mwidth.HasValue ?
 double.Parse(mwidth.ToString()) : 0;

            //缩略高度
            double sheight = mheight.HasValue ? double.Parse(mheight.ToString()) : 0;

            //从指定源图片,创建image对象
            string _sourceimg_common_mappath = "";

            //检測源文件
            bool checkfile = false;
            checkfile = System.IO.File.Exists(picpath);//FileExistMapPath(picpath, FileCheckModel.C, out _sourceimg_common_mappath);

            System.Drawing.Image _sourceimg_common = null;
            System.Drawing.Bitmap _currimg_common = null;
            System.Drawing.Graphics _g_common = null;

            if (checkfile)
            {
                //从源文件创建imgage
                _sourceimg_common = System.Drawing.Image.FromFile(picpath);
                #region 缩略模式
                //缩略模式
                switch (model)
                {
                    case ResizeType.X:

                        #region X模式

                        //依据给定尺寸,获取绘制比例
                        double _width_scale = swidth / _sourceimg_common.Width;
                        //高着比例
                        sheight = _sourceimg_common.Height * _width_scale;

                        #endregion
                        ; break;
                    case ResizeType.Y:
                        #region Y模式

                        //依据给定尺寸,获取绘制比例
                        double _height_scale = sheight / _sourceimg_common.Height;
                        //宽着比例
                        swidth = _sourceimg_common.Width * _height_scale;

                        #endregion
                        ; break;
                    case ResizeType.XY:
                        #region XY模式

                        //当选择XY模式时,mwidth,mheight为必须值
                        if (swidth < 0 || sheight < 0)
                        {
                            checkmessage.Append("error:XY模式,mwidth,mheight为必须值;");
                        }

                        #endregion
                        ; break;
                    default:
                        #region 默认XY模式

                        //当默认XY模式时,mwidth,mheight为必须值
                        if (swidth < 0 || sheight < 0)
                        {
                            checkmessage.Append("error:你当前未选择缩略模式,系统默认XY模式,mwidth,mheight为必须值;");
                        }

                        ; break;
                        #endregion
                }
                #endregion
            }
            else
            {
                checkmessage.Append("error:未能找到缩略原图片," + picpath + ";");
            }

            if (string.IsNullOrEmpty(checkmessage.ToString()))
            {
                //创建bitmap对象
                _currimg_common = new System.Drawing.Bitmap((int)swidth, (int)sheight);

                _g_common = Graphics.FromImage(_currimg_common);
                //画半透明确色底色
                Brush brush = new SolidBrush(Color.FromArgb(99, Color.White));
                _g_common.FillRectangle(brush, 0, 0, (float)swidth, (float)sheight);

                //设置画笔
                _g_common.CompositingMode = System.Drawing.Drawing2D.CompositingMode.SourceOver;
                _g_common.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
                _g_common.PixelOffsetMode = System.Drawing.Drawing2D.PixelOffsetMode.Half;

                int left = Math.Max(0, ((int)swidth - _sourceimg_common.Width) / 2);//图片左距离
                int top = Math.Max(0, ((int)sheight - _sourceimg_common.Height) / 2);//图片上距离
                int des_width = (int)swidth;
                int des_height = (int)sheight;
                int s_width = _sourceimg_common.Width;
                int s_height = _sourceimg_common.Height;
                if (des_width < s_width)
                {
                    des_width = s_width;
                }
                if (des_height < s_height)
                {
                    des_height = s_height;
                }

                //绘制图片
                _g_common.DrawImage(_sourceimg_common, new Rectangle(left, top, Math.Min(_sourceimg_common.Width, (int)swidth), Math.Min(_sourceimg_common.Height, (int)sheight)), new Rectangle(0, 0, _sourceimg_common.Width, _sourceimg_common.Height), GraphicsUnit.Pixel);

                //保存图片
                string _spath_common_mappath = "";

                //获取图片类型的hashcode值,生成图片后缀名
                int extro = imgtype.GetHashCode();

                string extend = extro == 0 ? ".jpg" : (extro == 1 ?
 ".gif" : (extro == 2 ?
 ".png" : ".jpg"));

                //全局文件名称
               // spath = spath + Guid.NewGuid().ToString() + extend;

                // FileExistMapPath(spath, FileCheckModel.M, out _spath_common_mappath);

                switch (imgtype)
                {
                    case ImageType.JPEG: _currimg_common.Save(spath, System.Drawing.Imaging.ImageFormat.Jpeg); break;
                    case ImageType.GIF: _currimg_common.Save(spath, System.Drawing.Imaging.ImageFormat.Gif); break;
                    case ImageType.PNG: _currimg_common.Save(spath, System.Drawing.Imaging.ImageFormat.Png); break;
                }

                //释放
                _sourceimg_common.Dispose();
                _currimg_common.Dispose();
                _g_common.Dispose();

                //处理原文件
                int filecachecode = filecache.GetHashCode();

                //文件缓存方式:Delete,删除原文件
                if (filecachecode == 1)
                {
                    System.IO.File.Delete(picpath);
                }

                //返回相对虚拟路径
                warning = "";
                return spath;
            }

            //释放
            if (_sourceimg_common != null)
            {
                _sourceimg_common.Dispose();
            }
            if (_currimg_common != null)
            {
                _currimg_common.Dispose();
            }
            if (_g_common != null)
            {
                _g_common.Dispose();
            }

            warning = checkmessage.ToString().TrimEnd(‘;‘);

            return "";
        }

    }
}

调用实例：

 ImageDealLib.Resizepic(
                        480,
                        480,
                        goodPicPath,
                        thumbPath,
                        CommonLib.ImageDealLib.ResizeType.X,
                        CommonLib.ImageDealLib.ImageType.JPEG,
                        CommonLib.ImageDealLib.FileCache.Save,
                        out warning);