需要在nuget安裝包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>
/// 生成圖檔縮略圖
/// </summary>
/// <remarks>
/// 建立時間：2021-2-5 16:32:19
/// </remarks>
public static class ImageHandle
{
/// <summary>
/// (推薦)生成縮略圖，圖檔流輸入，輸出圖檔流
/// </summary>
/// <param name="dWidth">要生成的寬度</param>
/// <param name="dHeight">要生成的高度</param>
/// <param name="flag">生成圖檔品質，1-100</param>
/// <param name="inputStream">輸入圖檔流</param>
/// <param name="outStream">輸出圖檔流</param>
public static void CompressImgByte(int dWidth, int dHeight, Stream inputStream, Stream outStream, int flag = 80, string arg = null)
{
System.Drawing.Image iSource = System.Drawing.Image.FromStream(inputStream);
var prop = iSource.PropertyItems.FirstOrDefault(x => x.Id == 274);
if (prop != null)
{
//讀取旋轉方向
byte[] buffed = prop.Value;
StringBuilder sbv = new StringBuilder();
foreach (var byteValue in buffed)
{
sbv.Append(byteValue.ToString("x2"));
}
string value2 = sbv.ToString();
//Console.WriteLine($"圖檔id {arg} 圖檔274裡面的值>" + value2);//linux測試
//windows擷取到旋轉的值為0600，linux旋轉值為0006
if (value2.Equals("0006") || value2.Equals("0600"))
{
//未做任何操作，此縮略圖會自動逆時針旋轉90度
//下面操作糾正旋轉，讓其順時針旋轉90度，讓圖檔回正
iSource.RotateFlip(RotateFlipType.Rotate90FlipNone);
}
}
System.Drawing.Imaging.ImageFormat tFormat = iSource.RawFormat;
//按比例縮放
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);
//清空畫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();
//以下代碼為儲存圖檔時，設定壓縮品質
System.Drawing.Imaging.EncoderParameters ep = new System.Drawing.Imaging.EncoderParameters();
long[] qy = new long[1];
qy[0] = flag;//設定壓縮的比例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是壓縮後的新路徑
}
else
{
ob.Save(outStream, tFormat);
}
}
catch (Exception ex)
{
string msg = ex.Message;
Console.WriteLine(msg);
}
finally
{
iSource.Dispose();
ob.Dispose();
}
}
/// <summary>
/// (推薦)生成縮略圖，圖檔流輸入，輸出圖檔流
/// </summary>
/// <param name="dWidth">要生成的寬度</param>
/// <param name="dHeight">要生成的高度</param>
/// <param name="filePath">輸入檔案路徑</param>
/// <param name="outFilePath">輸出儲存檔案路徑</param>
/// <param name="flag">生成的圖檔品質，0-100，預設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);
//檢測圖檔是否有旋轉
foreach (var item in iSource.PropertyItems)
{
//System.Diagnostics.Debug.WriteLine(item.Id);
if (item.Id == 274)
{
//讀取旋轉方向
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擷取到旋轉的值為0600，linux旋轉值為0006
if (value2.Equals("0006") || value2.Equals("0600"))
{
//未做任何操作，此縮略圖會自動逆時針旋轉90度
//下面操作糾正旋轉，讓其順時針旋轉90度，讓圖檔回正
iSource.RotateFlip(RotateFlipType.Rotate90FlipNone);
}
break;
}
}
System.Drawing.Imaging.ImageFormat tFormat = iSource.RawFormat;
//按比例縮放
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);
//清空畫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();
//以下代碼為儲存圖檔時，設定壓縮品質
System.Drawing.Imaging.EncoderParameters ep = new System.Drawing.Imaging.EncoderParameters();
long[] qy = new long[1];
qy[0] = flag;//設定壓縮的比例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是壓縮後的新路徑
}
else
{
ob.Save(outFilePath, tFormat);
}
}
catch (Exception ex)
{
string msg = ex.Message;
Console.WriteLine(msg);
}
finally
{
iSource.Dispose();
ob.Dispose();
}
}
}
}
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