/// <summary>
/// 将图片大小标准化(4M限制)
/// </summary>
/// <param name="image"></param>
/// <param name="width">压缩目标宽,会按原比例缩放</param>
/// <param name="height">压缩目标高,会按原比例缩放</param>
/// <returns></returns>
public static Bitmap miniSizeImage(System.Drawing.Image image, int width, int height)
{
int _height = 0;
int _width = 0;
//height much bigger , so height is the max number of size
if (image.Size.Height > image.Size.Width)
{
_height = height;
_width = (int)((double)image.Size.Width / image.Size.Height * height);
}
else
{
_height = (int)((double)image.Size.Height / image.Size.Width * width);
_width = width;
};
ResizeBicubic filter = new ResizeBicubic(_width, _height);
// apply the filter
try
{
return(filter.Apply(image as Bitmap));
}
catch (Exception ex)
{
return(image as Bitmap);
}
}
/// <summary>
/// 将图片大小标准化(4M限制)
/// </summary>
/// <param name="stream"></param>
/// <param name="width">压缩目标宽,会按原比例缩放</param>
/// <param name="height">压缩目标高,会按原比例缩放</param>
/// <param name="maxSize">压缩目标尺寸kb</param>///
/// <returns></returns>
public static Bitmap miniSizeImage(FileStream stream, int width, int height, int maxSize = 2 * 1024, bool forceMin = false)
{
//System.Drawing.Image image = System.Drawing.Image.FromStream(stream);
//if (!forceMin && stream.Length <= maxSize)
//{
// return image as Bitmap;
//}
//var length = new FileInfo(image).Length;
//return miniSizeImage(image, width, height);
Stream res = CompressImage(stream, 90, maxSize, true);
System.Drawing.Image image = System.Drawing.Image.FromStream(res);
return(image as Bitmap);
}
/// <summary>
/// 无损压缩图片
/// </summary>
/// <param name="sFile">原图片steam</param>
/// <param name="dFile">压缩后保存图片地址</param>
/// <param name="flag">压缩质量（数字越小压缩率越高）1-100</param>
/// <param name="size">压缩后图片的最大大小kb</param>
/// <param name="sfsc">是否是第一次调用</param>
/// <returns></returns>
public static Stream CompressImage(Stream sFile, int flag = 90, int size = 300, bool sfsc = true, Stream dFile = null)
{
//Console.WriteLine("sfile:" + sFile.Length);
//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
if (sfsc == true && sFile.Length < size * 1024)
{
//sFile.CopyTo(dFile);
return(sFile);
}
System.Drawing.Image iSource = System.Drawing.Image.FromStream(sFile);
ImageFormat tFormat = iSource.RawFormat;
int dHeight = iSource.Height / 2;
int dWidth = iSource.Width / 2;
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.Width * 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 = System.Drawing.Drawing2D.CompositingQuality.HighQuality;
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
g.InterpolationMode = System.Drawing.Drawing2D.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
{
if (dFile != null)
{
dFile.Close();
}
dFile = new MemoryStream();
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(fuckPath, jpegICIinfo, ep);//dFile是压缩后的
ob.Save(dFile, jpegICIinfo, ep);//dFile是压缩后的新路径
//Console.WriteLine("dfile:" + dFile.Length);
//Console.WriteLine("dfile byte:"+ (dFile as MemoryStream).ToArray().LongLength);
if (dFile.Length > 1024 * size)
{
flag -= 10;
if (flag >= 0)
{
dFile = CompressImage(sFile, flag, size, false, dFile);//递归压缩直到可行
}
else if (flag >= -100)
{
do
{
dFile = new MemoryStream();
var _radtio = (flag + 100) / 100.0;
System.Drawing.Image image = System.Drawing.Image.FromStream(sFile);
miniSizeImage(image, (int)(iSource.Width * _radtio), (int)(iSource.Height * _radtio)).Save(dFile, tFormat);
flag -= 10;
} while (dFile.Length > 1024 * size && flag >= -100);
}
else
{
dFile = sFile;
}
}
}
//
return(dFile);
}
catch
{
return(sFile);
}
finally
{
iSource.Dispose();
ob.Dispose();
}
}
