Finite le vacanze, tutti a metter le proprie foto online. Ecco una piccola utility (frutto di refactoring e copia/incolla) per ridimensionare ed alleggerire le immagini in un formato adatto al web:
Program.cs
1: using System;
2: using System.Collections.Generic;
3: using System.Linq;
4: using System.Text;
5: using System.IO;
6:
7: namespace ImageResizer
8: {
9: class Program
10: {
11: static void Main(string[] args)
12: {
13: Console.WriteLine("Seleziona cartella :");
14: string folder = Console.ReadLine();
15: Console.WriteLine("Seleziona larghezza immagine (es: 1024) :");
16: int width = Convert.ToInt32(Console.ReadLine());
17: Console.WriteLine("Seleziona altezza immagine (es: 768) :");
18: int height = Convert.ToInt32(Console.ReadLine());
19: Console.WriteLine("Seleziona qualità (0 - 100):");
20: int quality = Convert.ToInt32(Console.ReadLine());
21: string newFolder = folder + "_resized";
22: List<string> files = Directory.GetFiles(folder).ToList();
23: Directory.CreateDirectory(newFolder);
24:
25: foreach (string file in files)
26: {
27: ImageUtilities.ResizeImage(file, (newFolder + "\\" + Path.GetFileName(file)), width, height, true, quality);
28: }
29:
30: }
31:
32: }
33: }
E la classe che si occupa del lavoro sporco, ImageUtilities.cs
1: using System;
2: using System.Collections.Generic;
3: using System.Linq;
4: using System.Text;
5: using System.Drawing;
6: using System.Drawing.Imaging;
7:
8: namespace ImageResizer
9: {
10: /// <summary>
11: /// Provides various image untilities, such as high quality resizing and the ability to save a JPEG.
12: /// </summary>
13: public static class ImageUtilities
14: {
15: /// <summary>
16: /// A quick lookup for getting image encoders
17: /// </summary>
18: private static Dictionary<string, ImageCodecInfo> encoders = null;
19:
20: /// <summary>
21: /// A quick lookup for getting image encoders
22: /// </summary>
23: public static Dictionary<string, ImageCodecInfo> Encoders
24: {
25: //get accessor that creates the dictionary on demandd
26: get
27: {
28: //if the quick lookup isn't initialised, initialise it
29: if (encoders == null)
30: {
31: encoders = new Dictionary<string, ImageCodecInfo>();
32: }
33:
34: //if there are no codecs, try loading them
35: if (encoders.Count == 0)
36: {
37: //get all the codecs
38: foreach (ImageCodecInfo codec in ImageCodecInfo.GetImageEncoders())
39: {
40: //add each codec to the quick lookup
41: encoders.Add(codec.MimeType.ToLower(), codec);
42: }
43: }
44:
45: //return the lookup
46: return encoders;
47: }
48: }
49:
50: public static void ResizeImage(string OriginalFile, string NewFile, int NewWidth, int MaxHeight, bool OnlyResizeIfWider, int quality)
51: {
52: System.Drawing.Image FullsizeImage = System.Drawing.Image.FromFile(OriginalFile);
53:
54: // Prevent using images internal thumbnail
55: FullsizeImage.RotateFlip(System.Drawing.RotateFlipType.Rotate180FlipNone);
56: FullsizeImage.RotateFlip(System.Drawing.RotateFlipType.Rotate180FlipNone);
57:
58: if (OnlyResizeIfWider)
59: {
60: if (FullsizeImage.Width <= NewWidth)
61: {
62: NewWidth = FullsizeImage.Width;
63: }
64: }
65:
66: int NewHeight = FullsizeImage.Height * NewWidth / FullsizeImage.Width;
67: if (NewHeight > MaxHeight)
68: {
69: // Resize with height instead
70: NewWidth = FullsizeImage.Width * MaxHeight / FullsizeImage.Height;
71: NewHeight = MaxHeight;
72: }
73:
74: System.Drawing.Image NewImage = FullsizeImage.GetThumbnailImage(NewWidth, NewHeight, null, IntPtr.Zero);
75:
76: // Clear handle to original file so that we can overwrite it if necessary
77: FullsizeImage.Dispose();
78:
79: // Save resized picture
80: //NewImage.Save(NewFile);
81: SaveJpeg(NewFile, NewImage, quality);
82: }
83:
84:
85: /// <summary>
86: /// Saves an image as a jpeg image, with the given quality
87: /// </summary>
88: /// <param name="path">Path to which the image would be saved.</param>
89: /// <param name="quality">An integer from 0 to 100, with 100 being the
90: /// highest quality</param>
91: /// <exception cref="ArgumentOutOfRangeException">
92: /// An invalid value was entered for image quality.
93: /// </exception>
94: public static void SaveJpeg(string path, Image image, int quality)
95: {
96: //ensure the quality is within the correct range
97: if ((quality < 0) || (quality > 100))
98: {
99: //create the error message
100: string error = string.Format("La qualita' dell'immagine deve essere compresa tra 0 e 100. Il valore {0} non e' valido.", quality);
101: //throw a helpful exception
102: throw new ArgumentOutOfRangeException(error);
103: }
104:
105: //create an encoder parameter for the image quality
106: EncoderParameter qualityParam = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, quality);
107: //get the jpeg codec
108: ImageCodecInfo jpegCodec = GetEncoderInfo("image/jpeg");
109:
110: //create a collection of all parameters that we will pass to the encoder
111: EncoderParameters encoderParams = new EncoderParameters(1);
112: //set the quality parameter for the codec
113: encoderParams.Param[0] = qualityParam;
114: //save the image using the codec and the parameters
115: image.Save(path, jpegCodec, encoderParams);
116: }
117:
118: /// <summary>
119: /// Returns the image codec with the given mime type
120: /// </summary>
121: public static ImageCodecInfo GetEncoderInfo(string mimeType)
122: {
123: //do a case insensitive look at the mime type
124: mimeType = mimeType.ToLower();
125:
126: //the codec to return, default to null
127: ImageCodecInfo foundCodec = null;
128:
129: //if we have the encoder, get it to return
130: if (Encoders.ContainsKey(mimeType))
131: {
132: //pull the codec from the lookup
133: foundCodec = Encoders[mimeType];
134: }
135:
136: return foundCodec;
137: }
138: }
139:
140: }
