/// <summary>
/// For testing, see if we can write a png ourself that can be opened by .Net png.
/// </summary>
/// <param name="image">The image to write to png format</param>
/// <param name="filename">The string filename</param>
public void Write(Bitmap image, string filename)
{
if (File.Exists(filename)) File.Delete(filename);
Stream f = new FileStream(filename, FileMode.CreateNew, FileAccess.Write, FileShare.None, 1000000);
WriteSignature(f);
PngHeader header = new PngHeader(image.Width, image.Height);
header.Write(f);
WriteSrgb(f);
byte[] refImage = GetBytesFromImage(image);
byte[] filtered = Filter(refImage, 0, refImage.Length, image.Width*4);
byte[] compressed = Deflate.Compress(filtered);
WriteIDat(f, compressed);
WriteEnd(f);
f.Flush();
f.Close();
}
/// <summary>
/// Reads the important content from the stream of bytes
/// </summary>
/// <param name="stream"></param>
public static PngHeader FromBytes(Stream stream)
{
byte[] vals = new byte[25];
stream.Read(vals, 0, 25);
int w = (int)BitConverter.ToUInt32(vals, 9);
int h = (int)BitConverter.ToUInt32(vals, 13);
PngHeader result = new PngHeader(w, h);
result.BitDepth = (BitDepths)vals[17];
result.ColorType = (ColorTypes) vals[18];
result.InterlaceMethod = (InterlaceMethods) vals[21];
return result;
}