Encoder.Quality Encoder.Quality Encoder.Quality Encoder.Quality Field

定義

品質パラメーター カテゴリのグローバル一意識別子を使用して初期化される Encoder オブジェクトを取得します。Gets an Encoder object that is initialized with the globally unique identifier for the quality parameter category.

public: static initonly System::Drawing::Imaging::Encoder ^ Quality;
public static readonly System.Drawing.Imaging.Encoder Quality;
 staticval mutable Quality : System.Drawing.Imaging.Encoder
Public Shared ReadOnly Quality As Encoder 

フィールド値

次の例ではBitmap 、BMP ファイルからオブジェクトを作成します。The following example creates a Bitmap object from a BMP file. このコードでは、3つの JPEG ファイルにビットマップを保存します。それぞれの品質レベルが異なります。The code saves the bitmap to three JPEG files, each with a different quality level.

#using <System.Drawing.dll>

using namespace System;
using namespace System::Drawing;
using namespace System::Drawing::Imaging;
static ImageCodecInfo^ GetEncoderInfo( ImageFormat^ format );
int main()
{
   Bitmap^ myBitmap;
   ImageCodecInfo^ myImageCodecInfo;
   Encoder^ myEncoder;
   EncoderParameter^ myEncoderParameter;
   EncoderParameters^ myEncoderParameters;
   
   // Create a Bitmap object based on a BMP file.
   myBitmap = gcnew Bitmap( "Shapes.bmp" );
   
   // Get an ImageCodecInfo object that represents the JPEG codec.
   myImageCodecInfo = GetEncoderInfo( ImageFormat->Jpeg );
   
   // Create an Encoder object based on the GUID
   // for the Quality parameter category.
   myEncoder = Encoder::Quality;
   
   // Create an EncoderParameters object.
   // An EncoderParameters object has an array of EncoderParameter
   // objects. In this case, there is only one
   // EncoderParameter object in the array.
   myEncoderParameters = gcnew EncoderParameters( 1 );
   
   // Save the bitmap as a JPEG file with quality level 25.
   myEncoderParameter = gcnew EncoderParameter( myEncoder,__int64(25) );
   myEncoderParameters->Param[ 0 ] = myEncoderParameter;
   myBitmap->Save( "Shapes025.jpg", myImageCodecInfo, myEncoderParameters );
   
   // Save the bitmap as a JPEG file with quality level 50.
   myEncoderParameter = gcnew EncoderParameter( myEncoder,__int64(50) );
   myEncoderParameters->Param[ 0 ] = myEncoderParameter;
   myBitmap->Save( "Shapes050.jpg", myImageCodecInfo, myEncoderParameters );
   
   // Save the bitmap as a JPEG file with quality level 75.
   myEncoderParameter = gcnew EncoderParameter( myEncoder,__int64(75) );
   myEncoderParameters->Param[ 0 ] = myEncoderParameter;
   myBitmap->Save( "Shapes075.jpg", myImageCodecInfo, myEncoderParameters );
}

static ImageCodecInfo^ GetEncoderInfo( ImageFormat^ format )
{
   int j;
   array<ImageCodecInfo^>^encoders;
   encoders = ImageCodecInfo::GetImageEncoders();
   for ( j = 0; j < encoders->Length; ++j )
   {
      if ( encoders[ j ]->FormatID == format->Guid)
            return encoders[ j ];

   }
   return nullptr;
}

using System;
using System.Drawing;
using System.Drawing.Imaging;
class Example_SetJPEGQuality
{
    public static void Main()
    {
        Bitmap myBitmap;
        ImageCodecInfo myImageCodecInfo;
        Encoder myEncoder;
        EncoderParameter myEncoderParameter;
        EncoderParameters myEncoderParameters;
                     
        // Create a Bitmap object based on a BMP file.
        myBitmap = new Bitmap("Shapes.bmp");
                     
        // Get an ImageCodecInfo object that represents the JPEG codec.
        myImageCodecInfo = GetEncoderInfo("image/jpeg");
                     
        // Create an Encoder object based on the GUID
                     
        // for the Quality parameter category.
        myEncoder = Encoder.Quality;
                     
        // Create an EncoderParameters object.
                     
        // An EncoderParameters object has an array of EncoderParameter
                     
        // objects. In this case, there is only one
                     
        // EncoderParameter object in the array.
        myEncoderParameters = new EncoderParameters(1);
                     
        // Save the bitmap as a JPEG file with quality level 25.
        myEncoderParameter = new EncoderParameter(myEncoder, 25L);
        myEncoderParameters.Param[0] = myEncoderParameter;
        myBitmap.Save("Shapes025.jpg", myImageCodecInfo, myEncoderParameters);
                     
        // Save the bitmap as a JPEG file with quality level 50.
        myEncoderParameter = new EncoderParameter(myEncoder, 50L);
        myEncoderParameters.Param[0] = myEncoderParameter;
        myBitmap.Save("Shapes050.jpg", myImageCodecInfo, myEncoderParameters);
                     
        // Save the bitmap as a JPEG file with quality level 75.
        myEncoderParameter = new EncoderParameter(myEncoder, 75L);
        myEncoderParameters.Param[0] = myEncoderParameter;
        myBitmap.Save("Shapes075.jpg", myImageCodecInfo, myEncoderParameters);
    }
    private static ImageCodecInfo GetEncoderInfo(String mimeType)
    {
        int j;
        ImageCodecInfo[] encoders;
        encoders = ImageCodecInfo.GetImageEncoders();
        for(j = 0; j < encoders.Length; ++j)
        {
            if(encoders[j].MimeType == mimeType)
                return encoders[j];
        }
        return null;
    }
}
Imports System.Drawing
Imports System.Drawing.Imaging


Class Example_SetJPEGQuality

    Public Shared Sub Main()
        Dim myBitmap As Bitmap
        Dim myImageCodecInfo As ImageCodecInfo
        Dim myEncoder As Encoder
        Dim myEncoderParameter As EncoderParameter
        Dim myEncoderParameters As EncoderParameters

        ' Create a Bitmap object based on a BMP file.
        myBitmap = New Bitmap("Shapes.bmp")

        ' Get an ImageCodecInfo object that represents the JPEG codec.
        myImageCodecInfo = GetEncoderInfo(ImageFormat.Jpeg)

        ' Create an Encoder object based on the GUID
        ' for the Quality parameter category.
        myEncoder = Encoder.Quality

        ' Create an EncoderParameters object.
        ' An EncoderParameters object has an array of EncoderParameter
        ' objects. In this case, there is only one
        ' EncoderParameter object in the array.
        myEncoderParameters = New EncoderParameters(1)

        ' Save the bitmap as a JPEG file with quality level 25.
        myEncoderParameter = New EncoderParameter(myEncoder, CType(25L, Int32))
        myEncoderParameters.Param(0) = myEncoderParameter
        myBitmap.Save("Shapes025.jpg", myImageCodecInfo, myEncoderParameters)

        ' Save the bitmap as a JPEG file with quality level 50.
        myEncoderParameter = New EncoderParameter(myEncoder, CType(50L, Int32))
        myEncoderParameters.Param(0) = myEncoderParameter
        myBitmap.Save("Shapes050.jpg", myImageCodecInfo, myEncoderParameters)

        ' Save the bitmap as a JPEG file with quality level 75.
        myEncoderParameter = New EncoderParameter(myEncoder, CType(75L, Int32))
        myEncoderParameters.Param(0) = myEncoderParameter
        myBitmap.Save("Shapes075.jpg", myImageCodecInfo, myEncoderParameters)

    End Sub

    Private Shared Function GetEncoderInfo(ByVal format As ImageFormat) As ImageCodecInfo
        Dim j As Integer
        Dim encoders() As ImageCodecInfo
        encoders = ImageCodecInfo.GetImageEncoders()

        j = 0
        While j < encoders.Length
            If encoders(j).FormatID = format.Guid Then
                Return encoders(j)
            End If
            j += 1
        End While
        Return Nothing

    End Function 'GetEncoderInfo
End Class 'Example_SetJPEGQuality

注釈

カテゴリQualityは、イメージの圧縮レベルを指定します。The Quality category specifies the level of compression for an image. を構築EncoderParameterするために使用する場合、品質カテゴリの有効な値の範囲は 0 ~ 100 です。When used to construct an EncoderParameter, the range of useful values for the quality category is from 0 to 100. 指定した数値が小さいほど、圧縮率が高くなり、イメージの品質が低下します。The lower the number specified, the higher the compression and therefore the lower the quality of the image. 0を指定すると、最低品質のイメージが表示され、最大値は100になります。Zero would give you the lowest quality image and 100 the highest.

イメージエンコーダーにパラメーターを渡すと、パラメーターはEncoderParameterオブジェクトにカプセル化されます。When you pass a parameter to an image encoder, the parameter is encapsulated in an EncoderParameter object. EncoderParameterオブジェクトのフィールドの1つは、パラメーターのカテゴリを指定する GUID です。One of the fields of the EncoderParameter object is a GUID that specifies the category of the parameter. Encoderクラスの静的フィールドを使用して、目的Encoderのカテゴリのパラメーターを含むを取得します。Use the static fields of the Encoder class to retrieve an Encoder that contains parameters of the desired category.

複数のカテゴリに属する受信パラメーター GDI+GDI+に組み込まれているイメージエンコーダー。The image encoders that are built into GDI+GDI+ receive parameters that belong to several categories. 次の表に、すべてのカテゴリと、各カテゴリに関連付けられている GUID の一覧を示します。The following table lists all the categories and the GUID associated with each category.

ChrominanceTable
f2e455dc-09b3-4316-8260-676ada32481cf2e455dc-09b3-4316-8260-676ada32481c

ColorDepth
66087055-ad66-4c7c-9a18-38a2310b833766087055-ad66-4c7c-9a18-38a2310b8337

Compression
e09d739d-ccd4-44ee-8eba-3fbf8be4fc58e09d739d-ccd4-44ee-8eba-3fbf8be4fc58

LuminanceTable
edb33bce-0266-4a77-b904-27216099e717edb33bce-0266-4a77-b904-27216099e717

Quality
1d5be4b5-fa4a-452d-9cdd-5db35105e7eb1d5be4b5-fa4a-452d-9cdd-5db35105e7eb

RenderMethod
6d42c53a-229a-4825-8bb7-5c99e2b9a8b86d42c53a-229a-4825-8bb7-5c99e2b9a8b8

SaveFlag
292266fc-ac40-47bf-8cfc-a85b89a655de292266fc-ac40-47bf-8cfc-a85b89a655de

ScanMethod
3a4e2661-3109-4e56-8536-42c156e7dcfa3a4e2661-3109-4e56-8536-42c156e7dcfa

Transformation
8d0eb2d1-a58e-4ea8-aa14-108074b7b6f98d0eb2d1-a58e-4ea8-aa14-108074b7b6f9

Version
24d18c76-814a-41a4-bf53-1c219cccf79724d18c76-814a-41a4-bf53-1c219cccf797

適用対象

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