C#/JS 压缩到指定大小的图片 (内存不足问题修改)

//因为浏览器安全问题，无法获取上传图片地址，需要先存一遍然后再获取地址作参数上传

var des = CompressImage(@"C:\Users\PC\Pictures\测试\1652344981(1).jpg", @"C:\Users\PC\Pictures\测试\ok.jpg");

Console.WriteLine(des);

Console.ReadLine();

///

/// 无损压缩图片

///

/// 原图片地址

/// 压缩后保存图片地址

/// 压缩质量（数字越小压缩率越高）1-100

/// 压缩后图片的最大大小

/// 是否是第一次调用

///

bool CompressImage(string sFile, string dFile, int flag = 90, int size = 200, bool sfsc = true)

{

//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);

if (sfsc == true && firstFileInfo.Length < size * 1024)

{

firstFileInfo.CopyTo(dFile); return true;

}

Image iSource = 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);

using (Graphics g = Graphics.FromImage(ob)) //原代码再服务器上经常爆内存不足

{

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);//dFile是压缩后的新路径

FileInfo fi = new FileInfo(dFile);

if (fi.Length > 1024 * size)

{

flag = flag - 10;

CompressImage(sFile, dFile, flag, size, false);

}

}

else

{

ob.Save(dFile, tFormat);

}

return true;

}

catch { return false; }

finally { iSource.Dispose(); ob.Dispose(); }

}

//JS版本

转至：https://blog.csdn.net/wrongyao/article/details/104807924