EncoderParameters 构造函数

定义

命名空间:

System.Drawing.Imaging

程序集:

System.Drawing.Common.dll

包:

System.Drawing.Common v8.0.0

初始化可包含指定数量的 EncoderParameters 对象的 EncoderParameter 类的新实例。

重载

EncoderParameters()	初始化可包含一个 EncoderParameters 对象的 EncoderParameter 类的新实例。
EncoderParameters(Int32)	初始化可包含指定数量的 EncoderParameters 对象的 EncoderParameter 类的新实例。

EncoderParameters()

Source:

EncoderParameters.cs

初始化可包含一个 EncoderParameters 对象的 EncoderParameter 类的新实例。

public:
 EncoderParameters();

public EncoderParameters ();

Public Sub New ()

示例

下面的代码示例演示如何创建和使用 EncoderParameters 对象。 若要运行此示例，请将代码粘贴到 Windows 窗体中， VaryQualityLevel 然后从窗体的构造函数调用 方法。 此示例需要位于 c：\处的名为 TestPhoto.jpg 的图像文件。

private void VaryQualityLevel()
{
    // Get a bitmap.
    Bitmap bmp1 = new Bitmap(@"c:\TestPhoto.jpg");
    ImageCodecInfo jpgEncoder = GetEncoder(ImageFormat.Jpeg);

    // Create an Encoder object based on the GUID
    // for the Quality parameter category.
    System.Drawing.Imaging.Encoder myEncoder =
        System.Drawing.Imaging.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.
    EncoderParameters myEncoderParameters = new EncoderParameters(1);

    EncoderParameter myEncoderParameter = new EncoderParameter(myEncoder, 50L);
    myEncoderParameters.Param[0] = myEncoderParameter;
    bmp1.Save(@"c:\TestPhotoQualityFifty.jpg", jpgEncoder, myEncoderParameters);

    myEncoderParameter = new EncoderParameter(myEncoder, 100L);
    myEncoderParameters.Param[0] = myEncoderParameter;
    bmp1.Save(@"c:\TestPhotoQualityHundred.jpg", jpgEncoder, myEncoderParameters);

    // Save the bitmap as a JPG file with zero quality level compression.
    myEncoderParameter = new EncoderParameter(myEncoder, 0L);
    myEncoderParameters.Param[0] = myEncoderParameter;
    bmp1.Save(@"c:\TestPhotoQualityZero.jpg", jpgEncoder, myEncoderParameters);
}

Private Sub VaryQualityLevel()
    ' Get a bitmap.
    Dim bmp1 As New Bitmap("c:\TestPhoto.jpg")
    Dim jpgEncoder As ImageCodecInfo = GetEncoder(ImageFormat.Jpeg)

    ' Create an Encoder object based on the GUID
    ' for the Quality parameter category.
    Dim myEncoder As System.Drawing.Imaging.Encoder = System.Drawing.Imaging.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.
    Dim myEncoderParameters As New EncoderParameters(1)

    Dim myEncoderParameter As New EncoderParameter(myEncoder, 50&)
    myEncoderParameters.Param(0) = myEncoderParameter
    bmp1.Save("c:\TestPhotoQualityFifty.jpg", jpgEncoder, myEncoderParameters)

    myEncoderParameter = New EncoderParameter(myEncoder, 100&)
    myEncoderParameters.Param(0) = myEncoderParameter
    bmp1.Save("c:\TestPhotoQualityHundred.jpg", jpgEncoder, myEncoderParameters)

    ' Save the bitmap as a JPG file with zero quality level compression.
    myEncoderParameter = New EncoderParameter(myEncoder, 0&)
    myEncoderParameters.Param(0) = myEncoderParameter
    bmp1.Save("c:\TestPhotoQualityZero.jpg", jpgEncoder, myEncoderParameters)

End Sub

private ImageCodecInfo GetEncoder(ImageFormat format)
{
    ImageCodecInfo[] codecs = ImageCodecInfo.GetImageEncoders();

    foreach (ImageCodecInfo codec in codecs)
    {
        if (codec.FormatID == format.Guid)
        {
            return codec;
        }
    }
    
    return null;
}

Private Function GetEncoder(ByVal format As ImageFormat) As ImageCodecInfo

    Dim codecs As ImageCodecInfo() = ImageCodecInfo.GetImageEncoders()

    Dim codec As ImageCodecInfo
    For Each codec In codecs
        If codec.FormatID = format.Guid Then
            Return codec
        End If
    Next codec
    Return Nothing

End Function

注解

某些 Save 和 SaveAdd 方法接收 EncoderParameters 对象作为参数。 该 GetEncoderParameterList 方法返回 EncoderParameters 对象。

EncoderParameters(Int32)

Source:

EncoderParameters.cs

初始化可包含指定数量的 EncoderParameters 对象的 EncoderParameter 类的新实例。

public:
 EncoderParameters(int count);

public EncoderParameters (int count);

new System.Drawing.Imaging.EncoderParameters : int -> System.Drawing.Imaging.EncoderParameters

Public Sub New (count As Integer)

参数

count

Int32

一个整数，用以指定 EncoderParameter 对象可包含的 EncoderParameters 对象的数目。