Save JPEG images tùy chỉnh chất lượng

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Thủ thuật: Save JPEG images tùy chỉnh chất lượng
Tác giả: Kourosh Derakshan
Mô tả: Save JPEG images tùy chỉnh chất lượng

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Code VB.NET

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1. Dim myImage As Image = ' ... load the image somehow
2. ' Save the image with a quality of 50%
3. SaveJpeg(destImagePath, myImage, 50)

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Code: [Select all] [Expand/Collapse]

1. ' Please do not remove
2.     ' Written by Kourosh Derakshan
3.     '
4.  
5.     'add this!
6.     Imports System.Drawing.Imaging
7.  
8.  
9.     ' Saves an image as a jpeg image, with the given quality
10.     ' Gets
11.     '   path   - Path to which the image would be saved.
12.     '   quality - An integer from 0 to 100, with 100 being the
13.     '           highest quality
14.     Public Shared Sub SaveJpeg(ByVal path As String, ByVal img As Image, ByVal quality As Long)
15.         If ((quality < 0) OrElse (quality > 100)) Then
16.             Throw New ArgumentOutOfRangeException("quality must be between 0 and 100.")
17.         End If
18.  
19.         ' Encoder parameter for image quality
20.         Dim qualityParam As New EncoderParameter(Encoder.Quality, quality)
21.         ' Jpeg image codec
22.         Dim jpegCodec As ImageCodecInfo = GetEncoderInfo("image/jpeg")
23.  
24.         Dim encoderParams As New EncoderParameters(1)
25.         encoderParams.Param(0) = qualityParam
26.         img.Save(path, jpegCodec, encoderParams)
27.     End Sub
28.  
29.  
30.  
31.     ' Returns the image codec with the given mime type
32.     Private Shared Function GetEncoderInfo(ByVal mimeType As String) As ImageCodecInfo
33.         ' Get image codecs for all image formats
34.         Dim codecs As ImageCodecInfo() = ImageCodecInfo.GetImageEncoders()
35.  
36.         ' Find the correct image codec
37.         For i As Integer = 0 To codecs.Length - 1
38.             If (codecs(i).MimeType = mimeType) Then
39.                 Return codecs(i)
40.             End If
41.         Next i
42.  
43.         Return Nothing
44.     End Function

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Code C#:

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1. Image myImage = //... load the image somehow
2. // Save the image with a quality of 50%
3. SaveJpeg (destImagePath, myImage, 50);

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Code: [Select all] [Expand/Collapse]

1. // Please do not remove
2. // Written by Kourosh Derakshan
3. //
4.  
5. //add this!
6. using System.Drawing.Imaging;
7.  
8.                           /// <summary>
9.         /// Saves an image as a jpeg image, with the given quality
10.         /// </summary>
11.         /// <param name="path">Path to which the image would be saved.</param>
12.         // <param name="quality">An integer from 0 to 100, with 100 being the
13.         /// highest quality</param>
14.         public static void SaveJpeg (string path, Image img, int quality)
15.         {
16.             if (quality<0  ||  quality>100)
17.                 throw new ArgumentOutOfRangeException("quality must be between 0 and 100.");
18.  
19.              
20.             // Encoder parameter for image quality
21.             EncoderParameter qualityParam =
22.                 new EncoderParameter (Encoder.Quality, quality);
23.             // Jpeg image codec
24.             ImageCodecInfo   jpegCodec = GetEncoderInfo("image/jpeg");
25.  
26.             EncoderParameters encoderParams = new EncoderParameters(1);
27.             encoderParams.Param[0] = qualityParam;
28.  
29.             img.Save (path, jpegCodec, encoderParams);
30.         }
31.  
32.         /// <summary>
33.         /// Returns the image codec with the given mime type
34.         /// </summary>
35.         private static ImageCodecInfo GetEncoderInfo(string mimeType)
36.         {
37.             // Get image codecs for all image formats
38.             ImageCodecInfo[] codecs = ImageCodecInfo.GetImageEncoders();
39.  
40.             // Find the correct image codec
41.             for(int i=0; i<codecs.Length; i++)
42.                 if(codecs.MimeType == mimeType)
43.                     return codecs;
44.             return null;
45.         }

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