Encoder.Compression 字段

定义

命名空间:

System.Drawing.Imaging

程序集:

System.Drawing.Common.dll

包:

System.Drawing.Common v8.0.0

Source:

Encoder.cs

用压缩参数类别的全局唯一标识符初始化的 Encoder 对象。

public: static initonly System::Drawing::Imaging::Encoder ^ Compression;

public static readonly System.Drawing.Imaging.Encoder Compression;

 staticval mutable Compression : System.Drawing.Imaging.Encoder

Public Shared ReadOnly Compression As Encoder 

字段值

Encoder

示例

以下示例从 BMP 文件创建 Bitmap 对象。 代码将图像保存为具有 LZW 压缩的 TIFF 文件。

#using <System.Drawing.dll>

using namespace System;
using namespace System::Drawing;
using namespace System::Drawing::Imaging;
static ImageCodecInfo^ GetEncoderInfo( String^ mimeType );
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 TIFF codec.
   myImageCodecInfo = GetEncoderInfo( "image/tiff" );
   
   // Create an Encoder object based on the GUID
   // for the Compression parameter category.
   myEncoder = Encoder::Compression;
   
   // 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 TIFF file with LZW compression.
   myEncoderParameter = gcnew EncoderParameter( myEncoder,(__int64)EncoderValue::CompressionLZW );
   myEncoderParameters->Param[ 0 ] = myEncoderParameter;
   myBitmap->Save( "ShapesLZW.tif", myImageCodecInfo, myEncoderParameters );
}

static ImageCodecInfo^ GetEncoderInfo( String^ mimeType )
{
   int j;
   array<ImageCodecInfo^>^encoders;
   encoders = ImageCodecInfo::GetImageEncoders();
   for ( j = 0; j < encoders->Length; ++j )
   {
      if ( encoders[ j ]->MimeType == mimeType )
            return encoders[ j ];

   }
   return nullptr;
}

using System;
using System.Drawing;
using System.Drawing.Imaging;
class Example_SetTIFFCompression
{
    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 TIFF codec.
        myImageCodecInfo = GetEncoderInfo("image/tiff");
                     
        // Create an Encoder object based on the GUID
        // for the Compression parameter category.
        myEncoder = Encoder.Compression;
                     
        // 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 TIFF file with LZW compression.
        myEncoderParameter = new EncoderParameter(
            myEncoder,
            (long)EncoderValue.CompressionLZW);
        myEncoderParameters.Param[0] = myEncoderParameter;
        myBitmap.Save("ShapesLZW.tif", 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_SetTIFFCompression
    
    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 TIFF codec.
        myImageCodecInfo = GetEncoderInfo("image/tiff")
        
        ' Create an Encoder object based on the GUID
        ' for the Compression parameter category.
        myEncoder = Encoder.Compression
        
        ' 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 TIFF file with LZW compression.
        myEncoderParameter = New EncoderParameter(myEncoder, Fix(EncoderValue.CompressionLZW))
        myEncoderParameters.Param(0) = myEncoderParameter
        myBitmap.Save("ShapesLZW.tif", myImageCodecInfo, myEncoderParameters)
    
    End Sub
    
    Private Shared Function GetEncoderInfo(ByVal mimeType As String) As ImageCodecInfo 
        Dim j As Integer
        Dim encoders() As ImageCodecInfo
        encoders = ImageCodecInfo.GetImageEncoders()
        
        j = 0
        While j < encoders.Length
            If encoders(j).MimeType = mimeType Then
                Return encoders(j)
            End If
            j += 1
        End While
        Return Nothing
    
    End Function 'GetEncoderInfo
End Class

注解

将参数传递给图像编码器时，参数将封装在 对象中 EncoderParameter 。 对象的字段之 EncoderParameter 一是指定参数类别的 GUID。 使用 类的 Encoder 静态字段检索 Encoder 包含所需类别参数的 。

内置于 GDI+ 中的图像编码器接收属于多个类别的参数。 下表列出了所有类别以及与每个类别关联的 GUID。

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

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

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

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

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

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

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

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

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

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

另请参阅

• 在托管 GDI+ 中使用图像编码器和解码器