How to: Encode and Decode a JPEG Image
The following examples show how to decode and encode a JPEG image using the specific JpegBitmapDecoder and JpegBitmapEncoder objects.
Example
This example demonstrates how to decode a JPEG image using a JpegBitmapDecoder from a FileStream.
' Open a Stream and decode a JPEG image
Dim imageStreamSource As New FileStream("tulipfarm.jpg", FileMode.Open, FileAccess.Read, FileShare.Read)
Dim decoder As New JpegBitmapDecoder(imageStreamSource, BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.Default)
Dim bitmapSource As BitmapSource = decoder.Frames(0)
' Draw the Image
Dim myImage As New Image()
myImage.Source = bitmapSource
myImage.Stretch = Stretch.None
myImage.Margin = New Thickness(20)
// Open a Stream and decode a JPEG image
Stream imageStreamSource = new FileStream("tulipfarm.jpg", FileMode.Open, FileAccess.Read, FileShare.Read);
JpegBitmapDecoder decoder = new JpegBitmapDecoder(imageStreamSource, BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.Default);
BitmapSource bitmapSource = decoder.Frames[0];
// Draw the Image
Image myImage = new Image();
myImage.Source = bitmapSource;
myImage.Stretch = Stretch.None;
myImage.Margin = new Thickness(20);
// Open a Stream and decode a JPEG image
Stream^ imageStreamSource = gcnew FileStream("tulipfarm.jpg", FileMode::Open, FileAccess::Read, FileShare::Read);
JpegBitmapDecoder^ decoder = gcnew JpegBitmapDecoder(imageStreamSource, BitmapCreateOptions::PreservePixelFormat, BitmapCacheOption::Default);
BitmapSource^ bitmapSource = decoder->Frames[0];
// Draw the Image
Image^ myImage = gcnew Image();
myImage->Source = bitmapSource;
myImage->Stretch = Stretch::None;
myImage->Margin = System::Windows::Thickness(20);
This example demonstrates how to encode a BitmapSource into a JPEG image using a JpegBitmapEncoder.
Dim width As Integer = 128
Dim height As Integer = width
Dim stride As Integer = CType(width / 8, Integer)
Dim pixels(height * stride) As Byte
' Define the image palette
Dim myPalette As BitmapPalette = BitmapPalettes.Halftone256
' Creates a new empty image with the pre-defined palette
Dim image As BitmapSource = System.Windows.Media.Imaging.BitmapSource.Create(width, height, 96, 96, PixelFormats.Indexed1, myPalette, pixels, stride)
Dim stream As New FileStream("new.jpg", FileMode.Create)
Dim encoder As New JpegBitmapEncoder()
Dim myTextBlock As New TextBlock()
myTextBlock.Text = "Codec Author is: " + encoder.CodecInfo.Author.ToString()
encoder.FlipHorizontal = True
encoder.FlipVertical = False
encoder.QualityLevel = 30
encoder.Rotation = Rotation.Rotate90
encoder.Frames.Add(BitmapFrame.Create(image))
encoder.Save(stream)
int width = 128;
int height = width;
int stride = width / 8;
byte[] pixels = new byte[height * stride];
// Define the image palette
BitmapPalette myPalette = BitmapPalettes.Halftone256;
// Creates a new empty image with the pre-defined palette
BitmapSource image = BitmapSource.Create(
width,
height,
96,
96,
PixelFormats.Indexed1,
myPalette,
pixels,
stride);
FileStream stream = new FileStream("new.jpg", FileMode.Create);
JpegBitmapEncoder encoder = new JpegBitmapEncoder();
TextBlock myTextBlock = new TextBlock();
myTextBlock.Text = "Codec Author is: " + encoder.CodecInfo.Author.ToString();
encoder.FlipHorizontal = true;
encoder.FlipVertical = false;
encoder.QualityLevel = 30;
encoder.Rotation = Rotation.Rotate90;
encoder.Frames.Add(BitmapFrame.Create(image));
encoder.Save(stream);
int width = 128;
int height = width;
int stride = width / 8;
array<System::Byte>^ pixels = gcnew array<System::Byte>(height * stride);
// Define the image palette
BitmapPalette^ myPalette = BitmapPalettes::Halftone256;
// Creates a new empty image with the pre-defined palette.
BitmapSource^ image = BitmapSource::Create(
width, height,
96, 96,
PixelFormats::Indexed1,
myPalette,
pixels,
stride);
System::IO::FileStream^ stream = gcnew System::IO::FileStream("new.jpg", FileMode::Create);
JpegBitmapEncoder^ encoder = gcnew JpegBitmapEncoder();
TextBlock^ myTextBlock = gcnew System::Windows::Controls::TextBlock();
myTextBlock->Text = "Codec Author is: " + encoder->CodecInfo->Author->ToString();
encoder->FlipHorizontal = true;
encoder->FlipVertical = false;
encoder->QualityLevel = 30;
encoder->Rotation = Rotation::Rotate90;
encoder->Frames->Add(BitmapFrame::Create(image));
encoder->Save(stream);