标签：dFile tem C# 压缩 iSource Width new 图片 size
/// <summary>
/// 无损压缩图片
/// </summary>
/// <param name="sFile">原图片地址</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</param>
/// <param name="sfsc">是否是第一次调用</param>
/// <returns></returns>
public static MemoryStream CompressImage(string sFile, int flag, int size, bool sfsc)
{
//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
FileInfo firstFileInfo = new FileInfo(sFile);
MemoryStream dFile = new MemoryStream();
if (sfsc == true && firstFileInfo.Length < size * 1024)
{
FileStream file = new FileStream(sFile, FileMode.Open, FileAccess.Read);
byte[] bytes = new byte[file.Length];
file.Read(bytes, 0, (int)file.Length);
dFile.Write(bytes, 0, (int)file.Length);
file.Close();
return dFile;
}
System.Drawing.Image iSource = System.Drawing.Image.FromFile(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
{
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);
}
else
{
ob.Save(dFile, tFormat);
}
if (dFile.Length > 1024 * size)
{
flag = flag - 10;
dFile= CompressImage2(dFile, flag, size);
}
return dFile;
}
catch
{
return null;
}
finally
{
iSource.Dispose();
ob.Dispose();
}
}
public static MemoryStream CompressImage2(MemoryStream sFile, int flag, int size)
{
//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 (sFile.Length < size * 1024)
{
return sFile;
}
MemoryStream dFile = new MemoryStream();
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
{
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);
}
else
{
ob.Save(dFile, tFormat);
}
if (dFile.Length > 1024 * size)
{
flag = flag - 10;
return CompressImage2(dFile, flag, size);
}
return dFile;
}
catch
{
return null;
}
finally
{
iSource.Dispose();
ob.Dispose();
}
标签：dFile,tem,C#,压缩,iSource,Width,new,图片,size 来源： https://www.cnblogs.com/gxivwshjj/p/16074814.html
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