Image.Save 方法

Source:

Image.cs

Source:

Image.cs

Source:

Image.cs

public:
 void Save(System::String ^ filename, System::Drawing::Imaging::ImageCodecInfo ^ encoder, System::Drawing::Imaging::EncoderParameters ^ encoderParams);

public void Save (string filename, System.Drawing.Imaging.ImageCodecInfo encoder, System.Drawing.Imaging.EncoderParameters encoderParams);

public void Save (string filename, System.Drawing.Imaging.ImageCodecInfo encoder, System.Drawing.Imaging.EncoderParameters? encoderParams);

member this.Save : string * System.Drawing.Imaging.ImageCodecInfo * System.Drawing.Imaging.EncoderParameters -> unit

Public Sub Save (filename As String, encoder As ImageCodecInfo, encoderParams As EncoderParameters)

参数

例外

示例

以下示例从 BMP 文件创建 Bitmap 对象。 代码将位图保存到三个 JPEG 文件中，每个文件具有不同的质量级别。

#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

注解

不允许将映像保存到从中构造的同一个文件，并引发异常。

另请参阅

• 如何：设置 JPEG 压缩级别

Source:

Image.cs

Source:

Image.cs

Source:

Image.cs

public:
 void Save(System::IO::Stream ^ stream, System::Drawing::Imaging::ImageCodecInfo ^ encoder, System::Drawing::Imaging::EncoderParameters ^ encoderParams);

public void Save (System.IO.Stream stream, System.Drawing.Imaging.ImageCodecInfo encoder, System.Drawing.Imaging.EncoderParameters encoderParams);

public void Save (System.IO.Stream stream, System.Drawing.Imaging.ImageCodecInfo encoder, System.Drawing.Imaging.EncoderParameters? encoderParams);

member this.Save : System.IO.Stream * System.Drawing.Imaging.ImageCodecInfo * System.Drawing.Imaging.EncoderParameters -> unit

Public Sub Save (stream As Stream, encoder As ImageCodecInfo, encoderParams As EncoderParameters)

参数

例外

注解

不要将图像保存到用于构造映像的同一流中。 这样做可能会损坏流。

图像必须以零的偏移量保存到流中。 如果在保存图像之前已将任何其他数据写入流，则流中的图像数据将损坏。

Source:

Image.cs

Source:

Image.cs

Source:

Image.cs

public:
 void Save(System::String ^ filename, System::Drawing::Imaging::ImageFormat ^ format);

public void Save (string filename, System.Drawing.Imaging.ImageFormat format);

member this.Save : string * System.Drawing.Imaging.ImageFormat -> unit

Public Sub Save (filename As String, format As ImageFormat)

参数

例外

示例

下面的代码示例演示如何从类型构造位图，以及如何使用 Save 方法。 若要运行此示例，请将代码粘贴到 Windows 窗体中。 处理窗体的 Paint 事件，并调用 ConstructFromResourceSaveAsGif 方法，作为 e 传递 PaintEventArgs

private:
    void ConstructFromResourceSaveAsGif(PaintEventArgs^ e)
    {
        // Construct a bitmap from the button image resource.
        Bitmap^ bmp1 = gcnew Bitmap(Button::typeid, "Button.bmp");
        String^ savePath =  
            Environment::GetEnvironmentVariable("TEMP") + "\\Button.bmp";

        try
        {
            // Save the image as a GIF.
            bmp1->Save(savePath, System::Drawing::Imaging::ImageFormat::Gif);
        }
        catch (IOException^)
        {
            // Carry on regardless
        }

        // Construct a new image from the GIF file.
        Bitmap^ bmp2 = nullptr;
        if (File::Exists(savePath))
        {
            bmp2 = gcnew Bitmap(savePath);
        }

        // Draw the two images.
        e->Graphics->DrawImage(bmp1, Point(10, 10));

        // If bmp1 did not save to disk, bmp2 may be null
        if (bmp2 != nullptr)
        {
            e->Graphics->DrawImage(bmp2, Point(10, 40));
        }

        // Dispose of the image files.
        delete bmp1;
        if (bmp2 != nullptr)
        {
            delete bmp2;
        }
    }

private void ConstructFromResourceSaveAsGif(PaintEventArgs e)
{

    // Construct a bitmap from the button image resource.
    Bitmap bmp1 = new Bitmap(typeof(Button), "Button.bmp");

    // Save the image as a GIF.
    bmp1.Save("c:\\button.gif", System.Drawing.Imaging.ImageFormat.Gif);

    // Construct a new image from the GIF file.
    Bitmap bmp2 = new Bitmap("c:\\button.gif");

    // Draw the two images.
    e.Graphics.DrawImage(bmp1, new Point(10, 10));
    e.Graphics.DrawImage(bmp2, new Point(10, 40));

    // Dispose of the image files.
    bmp1.Dispose();
    bmp2.Dispose();
}

Private Sub ConstructFromResourceSaveAsGif(ByVal e As PaintEventArgs)

    ' Construct a bitmap from the button image resource.
    Dim bmp1 As New Bitmap(GetType(Button), "Button.bmp")

    ' Save the image as a GIF.
    bmp1.Save("c:\button.gif", System.Drawing.Imaging.ImageFormat.Gif)

    ' Construct a new image from the GIF file.
    Dim bmp2 As New Bitmap("c:\button.gif")

    ' Draw the two images.
    e.Graphics.DrawImage(bmp1, New Point(10, 10))
    e.Graphics.DrawImage(bmp2, New Point(10, 40))

    ' Dispose of the image files.
    bmp1.Dispose()
    bmp2.Dispose()
End Sub

Source:

Image.cs

Source:

Image.cs

Source:

Image.cs

public:
 void Save(System::IO::Stream ^ stream, System::Drawing::Imaging::ImageFormat ^ format);

public void Save (System.IO.Stream stream, System.Drawing.Imaging.ImageFormat format);

member this.Save : System.IO.Stream * System.Drawing.Imaging.ImageFormat -> unit

Public Sub Save (stream As Stream, format As ImageFormat)

参数

例外

注解

应避免将图像保存到用于构造它的同一流。 这样做可能会损坏流。

图像必须以零的偏移量保存到流中。 如果在保存图像之前已将任何其他数据写入流，则流中的图像数据将损坏。

Source:

Image.cs

Source:

Image.cs

Source:

Image.cs

public:
 void Save(System::String ^ filename);

public void Save (string filename);

member this.Save : string -> unit

Public Sub Save (filename As String)

参数

例外

示例

下面的代码示例演示如何调用 Save 方法。 此示例旨在与 Windows 窗体 一起使用。 Create包含名为 的按钮的Button5窗体。 将代码粘贴到窗体中，并将 方法与按钮的事件 Click 相关联。

private:
   void Button5_Click( System::Object^ /*sender*/, System::EventArgs^ /*e*/ )
   {
      try
      {
         if ( image1 != nullptr )
         {
            image1->Save( "c:\\myBitmap.bmp" );
            Button5->Text = "Saved file.";
         }
      }
      catch ( Exception^ ) 
      {
         MessageBox::Show( "There was a problem saving the file."
         "Check the file permissions." );
      }
   }

private void Button5_Click(System.Object sender, System.EventArgs e)
{
    try
    {
        if (image1 != null)
        {
            image1.Save("c:\\myBitmap.bmp");
            Button5.Text = "Saved file.";
        }
    }
    catch(Exception)
    {
        MessageBox.Show("There was a problem saving the file." +
            "Check the file permissions.");
    }
}

Private Sub Button5_Click(ByVal sender As System.Object, _
    ByVal e As System.EventArgs) Handles Button5.Click
    Try
        If (image1 IsNot Nothing) Then
            image1.Save("c:\myBitmap.bmp")
            Button5.Text = "Saved file."
        End If
    Catch ex As Exception
        MessageBox.Show("There was a problem saving the file." _
        & "Check the file permissions.")
    End Try

End Sub

注解

如果图像的文件格式不存在编码器，则使用可移植网络图形 (PNG) 编码器。 使用 Save 方法将图形图像另存为 WINDOWS 图元文件格式 (WMF) 或增强型图元文件格式 (EMF) 文件时，生成的文件将另存为可移植网络图形 (PNG) 文件。 发生此行为的原因是，.NET Framework的 GDI+ 组件没有可用于将文件另存为 .wmf 或.emf文件的编码器。

不允许将映像保存到从中构造的同一个文件，并引发异常。