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How to: Encode and Decode a GIF Image

The following examples show how to decode and encode a Graphics Interchange Format (GIF) image using the specific GifBitmapDecoder and GifBitmapEncoder objects.

This example demonstrates how to decode a GIF image using a GifBitmapDecoder from a FileStream.


// Open a Stream and decode a GIF image
Stream^ imageStreamSource = gcnew FileStream("tulipfarm.gif", FileMode::Open, FileAccess::Read, FileShare::Read);
GifBitmapDecoder^ decoder = gcnew GifBitmapDecoder(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 GIF image using a GifBitmapEncoder.

               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::WebPalette;

               // 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 = gcnew FileStream("new.gif", FileMode::Create);
               GifBitmapEncoder^ encoder = gcnew GifBitmapEncoder();
               TextBlock^ myTextBlock = gcnew TextBlock();
               myTextBlock->Text = "Codec Author is: " + encoder->CodecInfo->Author->ToString();
               encoder->Frames->Add(BitmapFrame::Create(image));
               encoder->Save(stream);
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