Convert HEIC to PNG programatically using System.Windows.Media.Imaging.WriteableBitmap

heic-to-png.cs

// Open the HEIC file named "filename.heic" in read mode using FileStream.
using (var fs = new FileStream("filename.heic", FileMode.Open))
{
    // Load the HEIC image from the file stream into a HeicImage object.
    HeicImage image = HeicImage.Load(fs);
    
    // Extract the pixel data from the HEIC image in the BGRA32 format, storing it in a byte array.
    var pixels = image.GetByteArray(Heic.Decoder.PixelFormat.Bgra32);
    // Retrieve the width and height of the HEIC image.
    var width = (int)image.Width;
    var height = (int)image.Height;
    
    // Create a WriteableBitmap object with the specified width, height, DPI, pixel format, and palette.
    var wbitmap = new WriteableBitmap(width, height, 72, 72, PixelFormats.Bgra32, null);
    // Define a rectangle covering the entire bitmap area.
    var rect = new Int32Rect(0, 0, width, height);
    // Write the extracted pixel data to the WriteableBitmap object.
    wbitmap.WritePixels(rect, pixels, 4 * width, 0);
    
    // Create or open a file stream for saving the converted image as "output.png".
    using FileStream saveStream = new FileStream("output.png", FileMode.OpenOrCreate);
    // Create a PngBitmapEncoder object to encode the bitmap as a JPEG image.
    PngBitmapEncoder encoder = new PngBitmapEncoder();
    // Add the bitmap frame to the encoder.
    encoder.Frames.Add(BitmapFrame.Create(wbitmap));
    // Save the encoded image to the file stream.
    encoder.Save(saveStream);
}