/// <summary>
/// Load the specified stream.
/// </summary>
/// <param name="stream">Stream representation of the png file.</param>
internal void Load(MemoryStream stream)
{
ms = stream;
// check file signature.
if (!Helper.IsBytesEqual(ms.ReadBytes(Frame.Signature.Length), Frame.Signature))
{
throw new Exception("File signature incorrect.");
}
// Read IHDR chunk.
IHDRChunk = new IHDRChunk(ms);
if (IHDRChunk.ChunkType != "IHDR")
{
throw new Exception("IHDR chunk must located before any other chunks.");
}
viewSize = new Size(IHDRChunk.Width, IHDRChunk.Height);
// Now let's loop in chunks
Chunk chunk;
Frame frame = null;
var otherChunks = new List <OtherChunk>();
bool isIDATAlreadyParsed = false;
do
{
if (ms.Position == ms.Length)
{
throw new Exception("IEND chunk expected.");
}
chunk = new Chunk(ms);
switch (chunk.ChunkType)
{
case "IHDR":
throw new Exception("Only single IHDR is allowed.");
case "acTL":
if (IsSimplePNG)
{
throw new Exception("acTL chunk must located before any IDAT and fdAT");
}
acTLChunk = new acTLChunk(chunk);
break;
case "IDAT":
// To be an APNG, acTL must located before any IDAT and fdAT.
if (acTLChunk == null)
{
IsSimplePNG = true;
}
// Only default image has IDAT.
defaultImage.IHDRChunk = IHDRChunk;
defaultImage.AddIDATChunk(new IDATChunk(chunk));
isIDATAlreadyParsed = true;
break;
case "fcTL":
// Simple PNG should ignore this.
if (IsSimplePNG)
{
continue;
}
if (frame != null && frame.IDATChunks.Count == 0)
{
throw new Exception("One frame must have only one fcTL chunk.");
}
// IDAT already parsed means this fcTL is used by FRAME IMAGE.
if (isIDATAlreadyParsed)
{
// register current frame object and build a new frame object
// for next use
if (frame != null)
{
frames.Add(frame);
}
frame = new Frame
{
IHDRChunk = IHDRChunk,
fcTLChunk = new fcTLChunk(chunk)
};
}
// Otherwise this fcTL is used by the DEFAULT IMAGE.
else
{
defaultImage.fcTLChunk = new fcTLChunk(chunk);
}
break;
case "fdAT":
// Simple PNG should ignore this.
if (IsSimplePNG)
{
continue;
}
// fdAT is only used by frame image.
if (frame == null || frame.fcTLChunk == null)
{
throw new Exception("fcTL chunk expected.");
}
frame.AddIDATChunk(new fdATChunk(chunk).ToIDATChunk());
break;
case "IEND":
// register last frame object
if (frame != null)
{
frames.Add(frame);
}
if (DefaultImage.IDATChunks.Count != 0)
{
DefaultImage.IENDChunk = new IENDChunk(chunk);
}
foreach (Frame f in frames)
{
f.IENDChunk = new IENDChunk(chunk);
}
break;
default:
otherChunks.Add(new OtherChunk(chunk));
break;
}
} while (chunk.ChunkType != "IEND");
// We have one more thing to do:
// If the default image is part of the animation,
// we should insert it into frames list.
if (defaultImage.fcTLChunk != null)
{
frames.Insert(0, defaultImage);
DefaultImageIsAnimated = true;
}
else //If it isn't animated it still needs the other chunks.
{
otherChunks.ForEach(defaultImage.AddOtherChunk);
}
// Now we should apply every chunk in otherChunks to every frame.
frames.ForEach(f => otherChunks.ForEach(f.AddOtherChunk));
}
public void Load(Stream stream)
{
chunks = new List <APNGChunk>();
pngs = new List <PNG>();
// Create a new header (should be 1 per file) and
// read it from the stream
var header = new APNGHeader();
try
{
header.Read(stream);
}
catch (Exception)
{
stream.Close();
throw;
}
APNGChunk chunk;
PNG png = null;
// Read chunks from the stream until we reach the MEND chunk
do
{
// Read a generic Chunk
chunk = new APNGChunk();
try
{
chunk.Read(stream);
}
catch (Exception)
{
stream.Close();
throw;
}
// Take a look at the chunk type and decide what derived class to
// use to create a specific chunk
switch (chunk.ChunkType)
{
case acTLChunk.NAME:
if (headerChunk != null)
{
throw new ApplicationException(String.Format(
"Only one chunk of type {0} is allowed", chunk.ChunkType));
}
chunk = headerChunk = new acTLChunk(chunk);
break;
case MENDChunk.NAME:
chunk = new MENDChunk(chunk);
break;
case TERMChunk.NAME:
chunk = new TERMChunk(chunk);
break;
case BACKChunk.NAME:
chunk = new BACKChunk(chunk);
break;
case BKGDChunk.NAME:
chunk = new BKGDChunk(chunk);
break;
case fcTLChunk.NAME:
// This is the beginning of a new embedded PNG
chunk = new fcTLChunk(chunk);
png = new PNG {
FCTL = chunk as fcTLChunk, IHDR = ihdrChunk
};
pngs.Add(png);
break;
case IHDRChunk.NAME:
chunk = new IHDRChunk(chunk);
ihdrChunk = chunk as IHDRChunk;
break;
case IDATChunk.NAME:
chunk = new IDATChunk(chunk);
if (png != null)
{
png.IDAT = chunk as IDATChunk;
}
break;
case fdATChunk.NAME:
chunk = new fdATChunk(chunk);
if (png != null)
{
chunk.ChunkType = IDATChunk.NAME;
png.IDAT = new IDATChunk(chunk);
}
break;
case IENDChunk.NAME:
chunk = new IENDChunk(chunk);
for (var i = 0; i < pngs.Count; i++)
{
pngs[i].IEND = chunk as IENDChunk;
}
break;
default:
break;
}
// Add the chunk to our list of chunks
chunks.Add(chunk);
}while (chunk.ChunkType != IENDChunk.NAME);
}
/// <summary>
/// Adds an image as the next frame.
/// </summary>
/// <param name="image">Png frame.</param>
public void AddFrame(Image image)
{
//TODO: Handle different sizes
//Temporarily reject improper sizes.
if (IHDRChunk != null && (image.Width > IHDRChunk.Width || image.Height > IHDRChunk.Height))
{
throw new InvalidDataException("Frame must be less than or equal to the size of the other frames.");
}
APNG apng = APNG.FromImage(image);
if (IHDRChunk == null)
{
IHDRChunk = apng.IHDRChunk;
}
//Create acTL Chunk.
if (acTLChunk == null)
{
acTLChunk = new acTLChunk();
acTLChunk.PlayCount = 0;
}
uint sequenceNumber = (frames.Count == 0) ? 0 : (uint)(frames[frames.Count - 1].fcTLChunk.SequenceNumber + frames[frames.Count - 1].IDATChunks.Count);
//Create fcTL Chunk
fcTLChunk fctl = new fcTLChunk
{
SequenceNumber = sequenceNumber,
Width = (uint)image.Width,
Height = (uint)image.Height,
XOffset = 0,
YOffset = 0,
DelayNumerator = 100,
DelayDenominator = 1000,
DisposeOp = DisposeOps.APNGDisposeOpNone,
BlendOp = BlendOps.APNGBlendOpSource
};
//Set the default image if needed.
if (defaultImage.IDATChunks.Count == 0)
{
defaultImage = apng.DefaultImage;
defaultImage.fcTLChunk = fctl;
DefaultImageIsAnimated = true;
}
//Add all the frames from the png.
if (apng.IsSimplePNG)
{
Frame frame = apng.DefaultImage;
frame.fcTLChunk = fctl;
foreach (OtherChunk chunk in frame.OtherChunks)
{
if (!defaultImage.OtherChunks.Contains(chunk))
{
defaultImage.OtherChunks.Add(chunk);
}
}
frame.OtherChunks.Clear();
frames.Add(frame);
}
else
{
for (int i = 0; i < apng.FrameCount; ++i)
{
Frame frame = apng.Frames[i];
frame.fcTLChunk.SequenceNumber = sequenceNumber;
foreach (OtherChunk chunk in frame.OtherChunks)
{
if (!defaultImage.OtherChunks.Contains(chunk))
{
defaultImage.OtherChunks.Add(chunk);
}
}
frame.OtherChunks.Clear();
frames.Add(frame);
}
}
List <OtherChunk> otherChunks = defaultImage.OtherChunks;
// Now we should apply every chunk in otherChunks to every frame.
if (defaultImage != frames[0])
{
frames.ForEach(f => otherChunks.ForEach(f.AddOtherChunk));
}
else
{
for (int i = 1; i < frames.Count; ++i)
{
otherChunks.ForEach(frames[i].AddOtherChunk);
}
}
acTLChunk.FrameCount = (uint)frames.Count;
}
