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  • 使用C#进行图片转换格式,缩放,自动旋转,保留exif(转载)

    这几天心血来潮做了一个批量图片缩放,转换格式,并且可以根据exif的信息旋转图片,校正exif信息后保存的小程序.根据配置文件 指定需要的功能.

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    using System;
    using System.IO;
    using System.Drawing.Imaging;
    using System.Drawing;
    using System.Drawing.Drawing2D;
    using System.Runtime.InteropServices;
    using System.Text;
     
    namespace PhotoUtil
    {
        class Program
        {
            [DllImport("kernel32")]
            private static extern long GetPrivateProfileString(string section, string key,
                string def, StringBuilder retVal, int size, string filePath);
            private const String configFile = "Config.ini";
     
            public static void Main(string[] args)
            {
                DirectoryInfo workingDir = new DirectoryInfo(ReadConfig("General", "WorkingDir",Environment.CurrentDirectory));
                if (!workingDir.Exists)
                {
                    workingDir = new DirectoryInfo(Environment.CurrentDirectory);
                }
                int quality=int.Parse(ReadConfig("General", "Quality", "85"));
                bool needResize = Boolean.Parse(ReadConfig("ResizeImage", "Enable", "false"));
                int newWidth = int.Parse(ReadConfig("ResizeImage", "NewWidth", "800"));
                int newHeight = int.Parse(ReadConfig("ResizeImage", "NewHeight", "600"));
                bool padding = Boolean.Parse(ReadConfig("ResizeImage", "Padding", "false"));
                bool needRotate = Boolean.Parse(ReadConfig("RotateImage", "Enable", "true"));
                FileInfo[] files = workingDir.GetFiles();
                DirectoryInfo output = workingDir.CreateSubdirectory(DateTime.Now.ToString("yyyyMMdd") + "转换
                foreach (FileInfo i in files)
                {
                    String type = i.Extension.ToLower();
                    if (type.Contains("jpg") || type.Contains("jpeg") || (type.Contains("png")) || type.Contains("tif") || type.Contains("bmp"))
                    {
                        Image img = Image.FromFile(i.FullName);
                        if (needResize)
                        {
                            Console.WriteLine("Resizing " + i.FullName);
                            ResizeImage(ref img, newWidth, newHeight, padding);
                        }
                        if (needRotate)
                        {
                            Console.WriteLine("Rotating " + i.FullName);
                            RotateImage(img);
                        }
                        SaveAs(img, output.FullName+"\\"+i.Name, quality);
                    }
                }
                Console.ReadLine();
            }
     
            private static void SaveAs(Image img, string dest, long quality)
            {
                if (quality > 100 || quality < 1)
                {
                    quality = 85;
                }
                EncoderParameters para = new EncoderParameters();
                para.Param[0] = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, quality);
                String extension = new FileInfo(dest).Extension;
                ImageCodecInfo info = GetImageCodecInfoByExtension(extension);
                if (info != null)
                {
                    img.Save(dest, info, para);
                }
                else
                {
                    throw new Exception("Unrecognized  format \"" + extension + "\"!
                }
            }
     
            private static void ResizeImage(ref Image image, int expectDestWidth, int expectDestHeight,bool padding)
            {
                PropertyItem[] exif = image.PropertyItems;
                int targetWidth = 0;
                int targetHeight = 0;
                double srcHWRate = (double)image.Width / (double)image.Height;
                double expectHWRate = (double)expectDestWidth / (double)expectDestHeight;
                if (srcHWRate > expectHWRate)
                {
                    targetWidth = expectDestWidth;
                    targetHeight = System.Convert.ToInt32(Math.Round(expectDestWidth / srcHWRate, 0));
                }
                else
                {
                    targetHeight = expectDestHeight;
                    targetWidth = System.Convert.ToInt32(Math.Round(expectDestHeight * srcHWRate, 0));
                }
     
                Image bitmap = null;
                if (!padding)
                {
                    bitmap = new Bitmap(targetWidth, targetHeight);
                }
                else
                {
                    bitmap = new Bitmap(expectDestWidth, expectDestHeight);
                }
                Graphics g = Graphics.FromImage(bitmap);
                g.CompositingQuality = CompositingQuality.HighQuality;
                g.InterpolationMode = InterpolationMode.HighQualityBicubic;
                g.SmoothingMode = SmoothingMode.HighQuality;
                g.DrawImage(image, new Rectangle(0, 0, bitmap.Width, bitmap.Height), new Rectangle(0, 0, image.Width, image.Height), GraphicsUnit.Pixel);
                foreach (PropertyItem i in exif)
                {
                    if (i.Id == 40962)
                    {
                        i.Value = BitConverter.GetBytes(targetWidth);
                    }
                    else if (i.Id == 40963)
                    {
                        i.Value = BitConverter.GetBytes(targetHeight);
                    }
                    bitmap.SetPropertyItem(i);
                }
                g.Dispose();
                image.Dispose();
                image = bitmap;
            }
     
            private static string ReadConfig(String Section, String Key, String defaultValue)
            {
                if (File.Exists(configFile))
                {
                    StringBuilder temp = new StringBuilder(1024);
                    GetPrivateProfileString(Section, Key, String.Empty, temp, 1024, new FileInfo(configFile).FullName);
                    if (!String.IsNullOrEmpty(temp.ToString()))
                    {
                        return temp.ToString();
                    }
                    else
                    {
                        return defaultValue;
                    }
                }
                else
                {
                    return defaultValue;
                }
            }
     
            public static void RotateImage(Image img)
            {
                PropertyItem[] exif = img.PropertyItems;
                byte orientation = 0;
                foreach (PropertyItem i in exif)
                {
                    if (i.Id == 274)
                    {
                        orientation = i.Value[0];
                        i.Value[0] = 1;
                        img.SetPropertyItem(i);
                    }
                }
     
                switch (orientation)
                {
                    case 2:
                        img.RotateFlip(RotateFlipType.RotateNoneFlipX);
                        break;
                    case 3:
                        img.RotateFlip(RotateFlipType.Rotate180FlipNone);
                        break;
                    case 4:
                        img.RotateFlip(RotateFlipType.RotateNoneFlipY);
                        break;
                    case 5:
                        img.RotateFlip(RotateFlipType.Rotate90FlipX);
                        break;
                    case 6:
                        img.RotateFlip(RotateFlipType.Rotate90FlipNone);
                        break;
                    case 7:
                        img.RotateFlip(RotateFlipType.Rotate270FlipX);
                        break;
                    case 8:
                        img.RotateFlip(RotateFlipType.Rotate270FlipNone);
                        break;
                    default:
                        break;
                }
                foreach (PropertyItem i in exif)
                {
                    if (i.Id == 40962)
                    {
                        i.Value = BitConverter.GetBytes(img.Width);
                    }
                    else if (i.Id == 40963)
                    {
                        i.Value = BitConverter.GetBytes(img.Height);
                    }
                }
            }
     
            private static ImageCodecInfo GetImageCodecInfoByExtension(String extension)
            {
                ImageCodecInfo[] list = ImageCodecInfo.GetImageEncoders();
                foreach(ImageCodecInfo i in list)
                {
                    if (i.FilenameExtension.ToLower().Contains(extension.ToLower()))
                    {
                        return i;
                    }
                }
                return null;
            }
        }
    }

    配置文件名称:Config.ini,放在和程序同目录下,格式如下:
    [General]
    #工作目录
    WorkingDir=.
    #输出质量,1-100范围内的整数
    Quality=80

    [ResizeImage]
    #是否启用
    Enable=true
    #新的宽值和高值
    NewWidth=1024
    NewHeight=768
    #是否对超出原来比例的部分进行填充
    Padding=false

    #是否使用Exif中的旋转信息对图片进行旋转
    [RotateImage]
    Enable=true

    1.保留exif信息的技巧是获取原始的Image.PropertyItems,对新图片添加即可.
    2.关于Exif Orientation标志的定义 http://sylvana.net/jpegcrop/exif_orientation.html
    3.变更jpeg输出质量的方法:
    EncoderParameters para = new EncoderParameters();
    para.Param[0] = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, quality);
    //这里的quality是从1-100的long值,一开始想当然的以为1-100的值就用了byte,结果出错了.
    最后调用Image.Save(String, ImageCodecInfo, EncoderParameters)来进行输出.
    4.进行缩放/旋转后需要调整原始的exif信息,id查文档可知.列出一些
    id=40962,width
    id=40963,height
    id=274,orientation type
    对PropertyItem信息设置完了别忘了Image.SetPropertyItem(PropertyItem)添加到image中,我出一个很 傻的bug,就是在修改了orientation type=1之后没有SetPropertyItem,于是导致图片实际被旋转至正确角度了,但是用ACDSee打开后可以看到exif的旋转信息依旧是 原来的值.

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  • 原文地址:https://www.cnblogs.com/sandea/p/3294254.html
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