图片压缩源码：将图片保持长宽比按指定展位大小压缩

C#语言基础

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开发语言：C#
实例大小：6.99M
下载次数：30
浏览次数：204
发布时间：2020-04-06
实例类别：C#语言基础
发布人：hongyuhlz2008
文件格式：.rar
所需积分：2

相关标签：上传图片压缩图片上传

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实例介绍

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【实例简介】上传图片保持长宽比按指定展位大小压缩
【实例截图】只需设定展位的长，宽和压缩比例。
【核心代码】

        /* <summary>
            无损压缩图片
            </summary>
            <param name="sFile">原图片</param>
            <param name="dFile">压缩后保存位置</param>
            <param name="dHeight">高度</param>
            <param name="dWidth">宽度</param>
            <param name="flag">压缩质量 1-100</param>
            <returns></returns> */
        public bool GetPicThumbnail(string sFile, string dFile, int dHeight, int dWidth, int flag)
        {
            System.Drawing.Image iSource;
            try {
                iSource = System.Drawing.Image.FromFile(sFile);
            }
            catch(Exception){
                return false;
            }

            ImageFormat tFormat = iSource.RawFormat;
            int sW = 0, sH = 0;
            //按比例缩放
            Size tem_size = new Size(iSource.Width, iSource.Height);
            if (tem_size.Width > dHeight || tem_size.Width > dWidth)
            {
                if ((tem_size.Width * dHeight) > (tem_size.Height * dWidth))
                {
                    sW = dWidth;
                    sH = (dWidth * tem_size.Height) / tem_size.Width;
                }
                else
                {
                    sH = dHeight;
                    sW = (tem_size.Width * dHeight) / tem_size.Height;
                }
            }
            else
            {
                sW = tem_size.Width;
                sH = tem_size.Height;
            }

            Bitmap ob = new Bitmap(dWidth, dHeight);
            Graphics g = Graphics.FromImage(ob);
            g.Clear(Color.WhiteSmoke);
            g.CompositingQuality = CompositingQuality.HighQuality;
            g.SmoothingMode = SmoothingMode.HighQuality;
            g.InterpolationMode = InterpolationMode.HighQualityBicubic;
            g.DrawImage(iSource, new Rectangle((dWidth - sW) / 2, (dHeight - sH) / 2, sW, sH), 0, 0, iSource.Width, iSource.Height, GraphicsUnit.Pixel);
            g.Dispose();
            //以下代码为保存图片时，设置压缩质量
            EncoderParameters ep = new EncoderParameters();
            long[] qy = new long[1];
            qy[0] = flag;//设置压缩的比例1-100
            EncoderParameter eParam = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, qy);
            ep.Param[0] = eParam;
            try
            {
                ImageCodecInfo[] arrayICI = ImageCodecInfo.GetImageEncoders();

ImageCodecInfo jpegICIinfo = null;

                for (int x = 0; x < arrayICI.Length; x )
                {
                    if (arrayICI[x].FormatDescription.Equals("JPEG"))
                    {
                        jpegICIinfo = arrayICI[x];
                        break;
                    }
                }
                if (jpegICIinfo != null)
                {
                    ob.Save(dFile, jpegICIinfo, ep);//dFile是压缩后的新路径
                }
                else
                {
                    ob.Save(dFile, tFormat);
                }
                return true;
            }
            catch
            {
                return false;
            }
            finally
            {
                iSource.Dispose();
                ob.Dispose();

}
}

标签： 上传图片压缩图片上传

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