本文主要是介绍.net5生成图片缩略图，有旋转的缩略图生成回正图片，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
需要在nuget安装包System.Drawing.Common
using System;
using System.Collections.Generic;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;namespace WebNetCore5_Img_Storage.Model.Tool
{/// <summary>/// 生成图片缩略图/// </summary>/// <remarks>/// 创建时间：2021-2-5 16:32:19/// </remarks>public static class ImageHandle{/// <summary>/// (推荐)生成缩略图，图片流输入，输出图片流/// </summary>/// <param name="dWidth">要生成的宽度</param>/// <param name="dHeight">要生成的高度</param>/// <param name="flag">生成图片质量，1-100</param>/// <param name="inputStream">输入图片流</param>/// <param name="outStream">输出图片流</param>public static void CompressImgByte(int dWidth, int dHeight, Stream inputStream, Stream outStream, int flag = 80, string arg = null){inputStream.Position = 0;System.Drawing.Image iSource = System.Drawing.Image.FromStream(inputStream);var prop = iSource.PropertyItems.FirstOrDefault(x => x.Id == 274);if (prop != null){//读取旋转方向byte[] buffed = prop.Value;StringBuilder sbv = new StringBuilder();foreach (var byteValue in buffed){sbv.Append(byteValue.ToString("x2"));} string value2 = sbv.ToString();//Console.WriteLine($"图片id {arg} 图片274里面的值>" + value2);//linux测试//windows获取到旋转的值为0600，linux旋转值为0006if (value2.Equals("0006") || value2.Equals("0600")){//未做任何操作，此缩略图会自动逆时针旋转90度//下面操作纠正旋转，让其顺时针旋转90度，让图片回正iSource.RotateFlip(RotateFlipType.Rotate90FlipNone);}}System.Drawing.Imaging.ImageFormat tFormat = iSource.RawFormat;//按比例缩放 if (dWidth > 0 && iSource.Width > dWidth && iSource.Width > iSource.Height){dHeight = dWidth * iSource.Height / iSource.Width;}else if (dWidth > 0 && dHeight == 0 && iSource.Width > dWidth){dHeight = dWidth * iSource.Height / iSource.Width;}else if (dWidth == 0 && dHeight > 0 && iSource.Width > iSource.Height){dWidth = dHeight * iSource.Width / iSource.Height;}else if (dHeight > iSource.Height || dWidth > iSource.Width){dWidth = iSource.Width;dHeight = iSource.Height;}else if (dHeight > 0 && iSource.Width < iSource.Height){dWidth = dHeight * iSource.Width / iSource.Height;}else{dWidth = iSource.Width;dHeight = iSource.Height;}Bitmap ob = new Bitmap(dWidth, dHeight);//ob.SetResolution(72,72);Graphics g = Graphics.FromImage(ob);//清空画布并以透明背景色填充g.Clear(System.Drawing.Color.Transparent);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(0, 0, dWidth, dHeight), 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 System.Drawing.Imaging.EncoderParameters ep = new System.Drawing.Imaging.EncoderParameters();long[] qy = new long[1];qy[0] = flag;//设置压缩的比例1-100 System.Drawing.Imaging.EncoderParameter eParam = new System.Drawing.Imaging.EncoderParameter(System.Drawing.Imaging.Encoder.Quality, qy);ep.Param[0] = eParam;try{System.Drawing.Imaging.ImageCodecInfo[] arrayICI = System.Drawing.Imaging.ImageCodecInfo.GetImageEncoders();System.Drawing.Imaging.ImageCodecInfo jpegICIinfo = arrayICI.FirstOrDefault(x => x.FormatDescription.Equals("JPEG"));if (jpegICIinfo != null){//ob.Save("d://" + DateTime.Now.Ticks + ".jpg", jpegICIinfo, ep);ob.Save(outStream, jpegICIinfo, ep);//dFile是压缩后的新路径}else{ob.Save(outStream, tFormat);}}catch (Exception ex){string msg = ex.Message;Console.WriteLine(msg);}finally{iSource.Dispose();ob.Dispose();}}/// <summary>/// (推荐)生成缩略图，图片流输入，输出图片流/// </summary>/// <param name="dWidth">要生成的宽度</param>/// <param name="dHeight">要生成的高度</param>/// <param name="filePath">输入文件路径</param>/// <param name="outFilePath">输出保存文件路径</param>/// <param name="flag">生成的图片质量，0-100，默认80</param>public static void CompressImgFile(int dWidth, int dHeight, string filePath, string outFilePath, int flag = 80){System.Drawing.Image iSource = System.Drawing.Image.FromFile(filePath);//检测图片是否有旋转foreach (var item in iSource.PropertyItems){//System.Diagnostics.Debug.WriteLine(item.Id);if (item.Id == 274){//读取旋转方向byte[] buffed = item.Value;StringBuilder sbv = new StringBuilder();foreach (var byteValue in buffed){sbv.Append(byteValue.ToString("x2"));}//string value2 = string.Join("", buffed);string value2 = sbv.ToString();System.Diagnostics.Debug.WriteLine("方向=" + value2);//windows获取到旋转的值为0600，linux旋转值为0006if (value2.Equals("0006") || value2.Equals("0600")){//未做任何操作，此缩略图会自动逆时针旋转90度//下面操作纠正旋转，让其顺时针旋转90度，让图片回正iSource.RotateFlip(RotateFlipType.Rotate90FlipNone);}break;}}System.Drawing.Imaging.ImageFormat tFormat = iSource.RawFormat;//按比例缩放 if (dWidth > 0 && iSource.Width > dWidth && iSource.Width > iSource.Height){dHeight = dWidth * iSource.Height / iSource.Width;}else if (dWidth > 0 && dHeight == 0 && iSource.Width > dWidth){dHeight = dWidth * iSource.Height / iSource.Width;}else if (dWidth == 0 && dHeight > 0 && iSource.Width > iSource.Height){dWidth = dHeight * iSource.Width / iSource.Height;}else if (dHeight > iSource.Height || dWidth > iSource.Width){dWidth = iSource.Width;dHeight = iSource.Height;}else if (dHeight > 0 && iSource.Width < iSource.Height){dWidth = dHeight * iSource.Width / iSource.Height;}else{dWidth = iSource.Width;dHeight = iSource.Height;}Bitmap ob = new Bitmap(dWidth, dHeight);//ob.SetResolution(72,72);Graphics g = Graphics.FromImage(ob);//清空画布并以透明背景色填充g.Clear(System.Drawing.Color.Transparent);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(0, 0, dWidth, dHeight), 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 System.Drawing.Imaging.EncoderParameters ep = new System.Drawing.Imaging.EncoderParameters();long[] qy = new long[1];qy[0] = flag;//设置压缩的比例1-100 System.Drawing.Imaging.EncoderParameter eParam = new System.Drawing.Imaging.EncoderParameter(System.Drawing.Imaging.Encoder.Quality, qy);ep.Param[0] = eParam;try{System.Drawing.Imaging.ImageCodecInfo[] arrayICI = System.Drawing.Imaging.ImageCodecInfo.GetImageEncoders();System.Drawing.Imaging.ImageCodecInfo jpegICIinfo = null;// string imgExtend = tFormat.ToString().ToUpper();string imgExtend = "JPEG";for (int x = 0; x < arrayICI.Length; x++){if (arrayICI[x].FormatDescription.Equals(imgExtend)){jpegICIinfo = arrayICI[x];break;}}if (jpegICIinfo != null){ob.Save(outFilePath, jpegICIinfo, ep);//dFile是压缩后的新路径 }else{ob.Save(outFilePath, tFormat);}}catch (Exception ex){string msg = ex.Message;Console.WriteLine(msg);}finally{iSource.Dispose();ob.Dispose();}}}
}调用参考
输出流
string fileInput = "E:\\测试图片\\2023_11_07_155548.3179.jpg";string outFile = "E:\\测试图片\\2023_11_07_155548.3179_c2222.jpg";//ImageHandle.CompressImgFile(1300, 1300, fileInput, outFile);var fileByter= File.ReadAllBytes(fileInput);System.IO.Stream inStream = new System.IO.MemoryStream();inStream.Write(fileByter, 0, fileByter.Length);System.IO.Stream outStream = new System.IO.MemoryStream();//执行压缩图片ImageHandle.CompressImgByte(1300, 1300, inStream, outStream);outStream.Position = 0;//压缩后的图片byte[] fileYaSuoByte = new byte[outStream.Length];outStream.Read(fileYaSuoByte, 0, (int)outStream.Length);File.WriteAllBytes(outFile,fileYaSuoByte);这篇关于.net5生成图片缩略图，有旋转的缩略图生成回正图片的文章就介绍到这儿，希望我们推荐的文章对编程师们有所帮助！
