public static void Convert(PngHeader header, byte[] inData, byte[] outData)
{
int stride = header.Stride;
PngFilter decoder = new PngFilter(stride,header.BytesPerPixel);
int inOfs=1;
int outOfs= 0;
for(int row = 0; row < header.Height; row++)
{
decoder.Decode(inData,outData,inOfs,outOfs);
inOfs += stride+1;
outOfs += stride;
}
}
private void WritePng(string fileName, PngHeader header, byte[] rawData)
{
using (Stream stream = new FileStream(fileName,FileMode.Create))
{
using (PngBinaryWriter writer = new PngBinaryWriter(stream))
{
writer.WriteSignatur();
writer.WriteHeader(header);
using (Stream ms = new MemoryStream())
{
PngHelper.WriteRows(rawData,header,ms);
writer.WriteData(PngHelper.InflateEncode(ms));
}
writer.WriteEnd();
}
}
}
public void TestWriteCross()
{
string fileName = Path.Combine(desktop,"cross.png");
int n = 100;
PngHeader header = new PngHeader(n,n,1,ColorModel.Gray);
byte[] data = new byte[header.Stride*header.Height];
for(int i=0; i<n; i++)
{
SetPixel(data,i,i,header.Stride);
SetPixel(data,n-i,i,header.Stride);
SetPixel(data,n/2,i,header.Stride);
SetPixel(data,i,n/2,header.Stride);
}
WritePng(fileName,header,data);
}
public void WriteHeader(PngHeader header)
{
byte[] buffer = new byte[13];
Array.Copy(
BitConverter.GetBytes(
PngHelper.DWordToInt(header.Width)),
0,buffer,0,4);
Array.Copy(
BitConverter.GetBytes(
PngHelper.DWordToInt(header.Height)),
0,buffer,4,4);
buffer[8]=header.BitDepth;
buffer[9]=(byte)header.ColorModel;
buffer[10]=0; // compress
buffer[11]=0; // filter
buffer[12]=0; // no interlace
Write(new Chunk(buffer.Length,Png.IHDR,buffer));
}
public static byte[] CreateRawImage(PngHeader header)
{
return new byte[header.Stride*header.Height];
}
public static void WriteRows(byte[] data, PngHeader header, Stream stream)
{
int stride=header.Stride;
if(header.IsMonochrome)
{
int ofs = 0;
for(int row=0; row < header.Height; row++)
{
stream.WriteByte((byte)Filter.None);
stream.Write(data,ofs,stride);
ofs+=stride;
};
}
else
{
var lines=new Dictionary<Filter, byte[]>();
foreach(Filter filter in Enum.GetValues(typeof(Filter)))
lines.Add(filter,new byte[stride]);
PngFilter encoder = new PngFilter(stride,header.BytesPerPixel);
int ofs = 0;
for(int row=0; row < header.Height; row++)
{
Filter filter = encoder.Encode(data,ofs,lines);
stream.WriteByte((byte)filter);
stream.Write(lines[filter],0,stride);
ofs+=stride;
};
}
}
