Defines a decoder for Portable Network Graphics (PNG) encoded images.
(in PresentationCore.dll)
Visual Basic (Declaration)
Public NotInheritable Class PngBitmapDecoder _
Inherits BitmapDecoder
Dim instance As PngBitmapDecoder
public sealed class PngBitmapDecoder : BitmapDecoder
public ref class PngBitmapDecoder sealed : public BitmapDecoder
public final class PngBitmapDecoder extends BitmapDecoder
You cannot directly create an instance of this class in XAML.
The following examples show how to decode and encode a Portable Network Graphics (PNG) image using the specific PngBitmapDecoder and PngBitmapEncoder objects. For the complete sample, see PNG Encoder and Decoder Sample.
This example demonstrates how to decode a PNG image using a PngBitmapDecoder from a FileStream.
' Open a Stream and decode a PNG image
Dim imageStreamSource As New FileStream("smiley.png", FileMode.Open, FileAccess.Read, FileShare.Read)
Dim decoder As New PngBitmapDecoder(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 PNG image
Stream imageStreamSource = new FileStream("smiley.png", FileMode.Open, FileAccess.Read, FileShare.Read);
PngBitmapDecoder decoder = new PngBitmapDecoder(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 PNG image
Stream^ imageStreamSource = gcnew FileStream("smiley.png", FileMode::Open, FileAccess::Read, FileShare::Read);
PngBitmapDecoder^ decoder = gcnew PngBitmapDecoder(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 PNG image using a PngBitmapEncoder.
Dim width As Integer = 128
Dim height As Integer = 128
Dim stride As Integer = width
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.Indexed8, myPalette, pixels, stride)
Dim stream As New FileStream("new.png", FileMode.Create)
Dim encoder As New PngBitmapEncoder()
Dim myTextBlock As New TextBlock()
myTextBlock.Text = "Codec Author is: " + encoder.CodecInfo.Author.ToString()
encoder.Interlace = PngInterlaceOption.On
encoder.Frames.Add(BitmapFrame.Create(image))
encoder.Save(stream)
int width = 128;
int height = 128;
int stride = width;
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.Indexed8,
myPalette,
pixels,
stride);
FileStream stream = new FileStream("new.png", FileMode.Create);
PngBitmapEncoder encoder = new PngBitmapEncoder();
TextBlock myTextBlock = new TextBlock();
myTextBlock.Text = "Codec Author is: " + encoder.CodecInfo.Author.ToString();
encoder.Interlace = PngInterlaceOption.On;
encoder.Frames.Add(BitmapFrame.Create(image));
encoder.Save(stream);
int width = 128;
int height = 128;
int stride = width;
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::Indexed8,
myPalette,
pixels,
stride);
FileStream^ stream = gcnew FileStream("new.png", FileMode::Create);
PngBitmapEncoder^ encoder = gcnew PngBitmapEncoder();
TextBlock^ myTextBlock = gcnew TextBlock();
myTextBlock->Text = "Codec Author is: " + encoder->CodecInfo->Author->ToString();
encoder->Interlace = PngInterlaceOption::On;
encoder->Frames->Add(BitmapFrame::Create(image));
encoder->Save(stream);
System..::.Object
System.Windows.Threading..::.DispatcherObject
System.Windows.Media.Imaging..::.BitmapDecoder
System.Windows.Media.Imaging..::.PngBitmapDecoder
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
.NET Framework
Supported in: 3.5, 3.0
Reference
Other Resources