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@@ -647,6 +647,99 @@ namespace Masuit.Tools.Media
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}
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}
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+ /// <summary>
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+ /// 无损压缩图片
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+ /// </summary>
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+ /// <param name="src">原图片文件流</param>
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+ /// <param name="dest">压缩后图片文件流</param>
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+ /// <param name="flag">压缩质量(数字越小压缩率越高)1-100</param>
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+ /// <param name="size">压缩后图片的最大大小</param>
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+ /// <param name="sfsc">是否是第一次调用</param>
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+ /// <returns></returns>
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+ public static bool CompressImage(Stream src, Stream dest, int flag = 90, int size = 1024, bool sfsc = true)
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+ {
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+ //如果是第一次调用,原始图像的大小小于要压缩的大小,则直接复制文件,并且返回true
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+ if (sfsc && src.Length < size * 1024)
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+ {
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+ src.CopyTo(dest);
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+ return true;
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+ }
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+
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+ using (Image iSource = Image.FromStream(src))
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+ {
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+ ImageFormat tFormat = iSource.RawFormat;
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+ int dHeight = iSource.Height;
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+ int dWidth = iSource.Width;
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+ int sW, sH;
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+ //按比例缩放
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+ Size temSize = new Size(iSource.Width, iSource.Height);
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+ if (temSize.Width > dHeight || temSize.Width > dWidth)
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+ {
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+ if ((temSize.Width * dHeight) > (temSize.Width * dWidth))
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+ {
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+ sW = dWidth;
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+ sH = (dWidth * temSize.Height) / temSize.Width;
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+ }
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+ else
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+ {
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+ sH = dHeight;
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+ sW = (temSize.Width * dHeight) / temSize.Height;
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+ }
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+ }
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+ else
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+ {
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+ sW = temSize.Width;
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+ sH = temSize.Height;
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+ }
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+
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+ using (Bitmap bmp = new Bitmap(dWidth, dHeight))
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+ {
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+ using (Graphics g = Graphics.FromImage(bmp))
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+ {
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+ g.Clear(Color.WhiteSmoke);
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+ g.CompositingQuality = CompositingQuality.HighQuality;
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+ g.SmoothingMode = SmoothingMode.HighQuality;
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+ g.InterpolationMode = InterpolationMode.HighQualityBicubic;
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+ g.DrawImage(iSource, new Rectangle((dWidth - sW) / 2, (dHeight - sH) / 2, sW, sH), 0, 0, iSource.Width, iSource.Height, GraphicsUnit.Pixel);
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+ }
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+
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+ //以下代码为保存图片时,设置压缩质量
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+ using (EncoderParameters ep = new EncoderParameters())
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+ {
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+ long[] qy = new long[1];
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+ qy[0] = flag;//设置压缩的比例1-100
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+ using (EncoderParameter eParam = new EncoderParameter(Encoder.Quality, qy))
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+ {
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+ ep.Param[0] = eParam;
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+ try
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+ {
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+ ImageCodecInfo[] arrayIci = ImageCodecInfo.GetImageEncoders();
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+ ImageCodecInfo jpegIcIinfo = arrayIci.FirstOrDefault(t => t.FormatDescription.Equals("JPEG"));
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+ if (jpegIcIinfo != null)
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+ {
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+ bmp.Save(dest, jpegIcIinfo, ep);//dFile是压缩后的新路径
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+ if (dest.Length > 1024 * size)
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+ {
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+ flag = flag - 10;
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+ CompressImage(src, dest, flag, size, false);
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+ }
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+ }
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+ else
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+ {
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+ bmp.Save(dest, tFormat);
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+ }
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+ return true;
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+ }
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+ catch
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+ {
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+ return false;
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+ }
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+ }
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+ }
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+ }
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+ }
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+ }
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+
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#endregion
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#region 缩略图
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