public void SaveApng(string file, Png [] frames, ushort delay_num, ushort delay_density)
{
using (var w = new BinaryWriter(new FileStream(file, FileMode.Create)))
{
w.Write(signature);
PngIHDRChunk ihdr = (PngIHDRChunk)chunks.Find(d => d.IsType("IHDR"));
w.Write(ihdr.ToBytes());
w.Write(new PngacTLChunk((uint)(frames.Length + 1), 0).ToBytes());
uint sequence = 0;
w.Write(new PngfcTLChunk(ihdr, sequence++, delay_num, delay_density).ToBytes());
foreach (var chunk in chunks.FindAll(d => d.IsType("IDAT")))
{
w.Write(chunk.ToBytes());
}
foreach (Png frame in frames)
{
w.Write(new PngfcTLChunk(ihdr, sequence++, delay_num, delay_density).ToBytes());
foreach (var chunk in frame.chunks.FindAll(d => d.IsType("IDAT")))
{
w.Write(((PngIDATChunk)chunk).TofdATChunk(sequence++).ToBytes());
}
}
w.Write(chunks.Find(d => d.IsType("IEND")).ToBytes());
}
}
private PngChunk ReadChunk(BinaryReader reader, int size)
{
byte[] type = reader.ReadBytes(4);
string _type = Encoding.ASCII.GetString(type);
PngChunk chunk;
byte[] data = reader.ReadBytes(size);
switch (_type)
{
case "IHDR":
chunk = new PngIHDRChunk(data);
break;
case "IDAT":
chunk = new PngIDATChunk(data);
break;
default:
chunk = new PngChunk(type, data);
break;
}
uint read_crc = (uint)ToInteger(reader.ReadBytes(4));
uint calculated_crc = chunk.Crc();
if (read_crc != calculated_crc)
{
throw new Exception("CRCエラー");
}
return(chunk);
}
public PngfcTLChunk(PngIHDRChunk ihdr, uint sequence, ushort delay_num, ushort delay_density) : base("fcTL", new byte[26])
{
Array.Copy(ToBytes(sequence), 0, Data, 0, 4);
Array.Copy(ihdr.WidthBytes, 0, Data, 4, 4);
Array.Copy(ihdr.HeightBytes, 0, Data, 8, 4);
Array.Copy(ToBytes(delay_num), 0, Data, 20, 2);
Array.Copy(ToBytes(delay_density), 0, Data, 22, 2);
}
