/// <summary>
/// Write id signature and also "IHDR" chunk
/// </summary>
///
private void WriteSignatureAndIHDR()
{
CurrentChunkGroup = ChunksList.CHUNK_GROUP_0_IDHR;
PngHelperInternal.WriteBytes(outputStream, Hjg.Pngcs.PngHelperInternal.PNG_ID_SIGNATURE); // signature
PngChunkIHDR ihdr = new PngChunkIHDR(ImgInfo);
// http://www.libpng.org/pub/png/spec/1.2/PNG-Chunks.html
ihdr.Cols = ImgInfo.Cols;
ihdr.Rows = ImgInfo.Rows;
ihdr.Bitspc = ImgInfo.BitDepth;
int colormodel = 0;
if (ImgInfo.Alpha)
{
colormodel += 0x04;
}
if (ImgInfo.Indexed)
{
colormodel += 0x01;
}
if (!ImgInfo.Greyscale)
{
colormodel += 0x02;
}
ihdr.Colormodel = colormodel;
ihdr.Compmeth = 0; // compression method 0=deflate
ihdr.Filmeth = 0; // filter method (0)
ihdr.Interlaced = 0; // never interlace
ihdr.CreateRawChunk().WriteChunk(outputStream);
}
public void WriteSignatureAndIHDR()
{
CurrentChunkGroup = 0;
PngHelperInternal.WriteBytes(outputStream, PngHelperInternal.PNG_ID_SIGNATURE);
PngChunkIHDR obj = new PngChunkIHDR(ImgInfo)
{
Cols = ImgInfo.Cols,
Rows = ImgInfo.Rows,
Bitspc = ImgInfo.BitDepth
};
int num = 0;
if (ImgInfo.Alpha)
{
num += 4;
}
if (ImgInfo.Indexed)
{
num++;
}
if (!ImgInfo.Greyscale)
{
num += 2;
}
obj.Colormodel = num;
obj.Compmeth = 0;
obj.Filmeth = 0;
obj.Interlaced = 0;
obj.CreateRawChunk().WriteChunk(outputStream);
}
private void WriteSignatureAndIHDR()
{
CurrentChunkGroup = ChunksList.CHUNK_GROUP_0_IDHR;
PngHelperInternal.WriteBytes ( outputStream, Hjg.Pngcs.PngHelperInternal.PNG_ID_SIGNATURE ); // signature
PngChunkIHDR ihdr = new PngChunkIHDR ( ImgInfo );
ihdr.Cols = ImgInfo.Cols;
ihdr.Rows = ImgInfo.Rows;
ihdr.Bitspc = ImgInfo.BitDepth;
int colormodel = 0;
if ( ImgInfo.Alpha )
colormodel += 0x04;
if ( ImgInfo.Indexed )
colormodel += 0x01;
if ( !ImgInfo.Greyscale )
colormodel += 0x02;
ihdr.Colormodel = colormodel;
ihdr.Compmeth = 0;
ihdr.Filmeth = 0;
ihdr.Interlaced = 0;
ihdr.CreateRawChunk ().WriteChunk ( outputStream );
}
/// <summary>
/// Constructs a PNGReader objet from a opened Stream
/// </summary>
/// <remarks>The constructor reads the signature and first chunk (IDHR)<seealso cref="FileHelper.CreatePngReader(string)"/>
/// </remarks>
///
/// <param name="inputStream"></param>
/// <param name="filename">Optional, can be the filename or a description.</param>
public PngReader(Stream inputStream, String filename)
{
this.filename = (filename == null) ? "" : filename;
this.inputStream = inputStream;
this.chunksList = new ChunksList(null);
this.metadata = new PngMetadata(chunksList);
this.offset = 0;
// set default options
this.CurrentChunkGroup = -1;
this.ShouldCloseStream = true;
this.MaxBytesMetadata = 5 * 1024 * 1024;
this.MaxTotalBytesRead = 200 * 1024 * 1024; // 200MB
this.SkipChunkMaxSize = 2 * 1024 * 1024;
this.SkipChunkIds = new string[] { "fdAT" };
this.ChunkLoadBehaviour = Hjg.Pngcs.Chunks.ChunkLoadBehaviour.LOAD_CHUNK_ALWAYS;
// starts reading: signature
byte[] pngid = new byte[8];
PngHelperInternal.ReadBytes(inputStream, pngid, 0, pngid.Length);
offset += pngid.Length;
if (!PngCsUtils.arraysEqual(pngid, PngHelperInternal.PNG_ID_SIGNATURE))
{
throw new PngjInputException("Bad PNG signature");
}
CurrentChunkGroup = ChunksList.CHUNK_GROUP_0_IDHR;
// reads first chunk IDHR
int clen = PngHelperInternal.ReadInt4(inputStream);
offset += 4;
if (clen != 13)
{
throw new Exception("IDHR chunk len != 13 ?? " + clen);
}
byte[] chunkid = new byte[4];
PngHelperInternal.ReadBytes(inputStream, chunkid, 0, 4);
if (!PngCsUtils.arraysEqual4(chunkid, ChunkHelper.b_IHDR))
{
throw new PngjInputException("IHDR not found as first chunk??? ["
+ ChunkHelper.ToString(chunkid) + "]");
}
offset += 4;
PngChunkIHDR ihdr = (PngChunkIHDR)ReadChunk(chunkid, clen, false);
bool alpha = (ihdr.Colormodel & 0x04) != 0;
bool palette = (ihdr.Colormodel & 0x01) != 0;
bool grayscale = (ihdr.Colormodel == 0 || ihdr.Colormodel == 4);
// creates ImgInfo and imgLine, and allocates buffers
ImgInfo = new ImageInfo(ihdr.Cols, ihdr.Rows, ihdr.Bitspc, alpha, grayscale, palette);
rowb = new byte[ImgInfo.BytesPerRow + 1];
rowbprev = new byte[rowb.Length];
rowbfilter = new byte[rowb.Length];
interlaced = ihdr.Interlaced == 1;
deinterlacer = interlaced ? new PngDeinterlacer(ImgInfo) : null;
// some checks
if (ihdr.Filmeth != 0 || ihdr.Compmeth != 0 || (ihdr.Interlaced & 0xFFFE) != 0)
{
throw new PngjInputException("compmethod or filtermethod or interlaced unrecognized");
}
if (ihdr.Colormodel < 0 || ihdr.Colormodel > 6 || ihdr.Colormodel == 1 ||
ihdr.Colormodel == 5)
{
throw new PngjInputException("Invalid colormodel " + ihdr.Colormodel);
}
if (ihdr.Bitspc != 1 && ihdr.Bitspc != 2 && ihdr.Bitspc != 4 && ihdr.Bitspc != 8 &&
ihdr.Bitspc != 16)
{
throw new PngjInputException("Invalid bit depth " + ihdr.Bitspc);
}
}
/// <summary>
/// Write id signature and also "IHDR" chunk
/// </summary>
///
private void WriteSignatureAndIHDR()
{
CurrentChunkGroup = ChunksList.CHUNK_GROUP_0_IDHR;
PngHelperInternal.WriteBytes(outputStream, Hjg.Pngcs.PngHelperInternal.PNG_ID_SIGNATURE); // signature
PngChunkIHDR ihdr = new PngChunkIHDR(ImgInfo);
// http://www.libpng.org/pub/png/spec/1.2/PNG-Chunks.html
ihdr.Cols = ImgInfo.Cols;
ihdr.Rows = ImgInfo.Rows;
ihdr.Bitspc = ImgInfo.BitDepth;
int colormodel = 0;
if (ImgInfo.Alpha)
colormodel += 0x04;
if (ImgInfo.Indexed)
colormodel += 0x01;
if (!ImgInfo.Greyscale)
colormodel += 0x02;
ihdr.Colormodel = colormodel;
ihdr.Compmeth = 0; // compression method 0=deflate
ihdr.Filmeth = 0; // filter method (0)
ihdr.Interlaced = 0; // never interlace
ihdr.CreateRawChunk().WriteChunk(outputStream);
}
public PngReader(Stream inputStream, string filename)
{
this.filename = ((filename == null) ? "" : filename);
this.inputStream = inputStream;
chunksList = new ChunksList(null);
metadata = new PngMetadata(chunksList);
offset = 0L;
CurrentChunkGroup = -1;
ShouldCloseStream = true;
MaxBytesMetadata = 5242880L;
MaxTotalBytesRead = 209715200L;
SkipChunkMaxSize = 2097152;
SkipChunkIds = new string[1]
{
"fdAT"
};
ChunkLoadBehaviour = ChunkLoadBehaviour.LOAD_CHUNK_ALWAYS;
byte[] array = new byte[8];
PngHelperInternal.ReadBytes(inputStream, array, 0, array.Length);
offset += array.Length;
if (!PngCsUtils.arraysEqual(array, PngHelperInternal.PNG_ID_SIGNATURE))
{
throw new PngjInputException("Bad PNG signature");
}
CurrentChunkGroup = 0;
int num = PngHelperInternal.ReadInt4(inputStream);
offset += 4L;
if (num != 13)
{
throw new Exception("IDHR chunk len != 13 ?? " + num.ToString());
}
byte[] array2 = new byte[4];
PngHelperInternal.ReadBytes(inputStream, array2, 0, 4);
if (!PngCsUtils.arraysEqual4(array2, ChunkHelper.b_IHDR))
{
throw new PngjInputException("IHDR not found as first chunk??? [" + ChunkHelper.ToString(array2) + "]");
}
offset += 4L;
PngChunkIHDR pngChunkIHDR = (PngChunkIHDR)ReadChunk(array2, num, skipforced: false);
bool alpha = (pngChunkIHDR.Colormodel & 4) != 0;
bool palette = (pngChunkIHDR.Colormodel & 1) != 0;
bool grayscale = pngChunkIHDR.Colormodel == 0 || pngChunkIHDR.Colormodel == 4;
ImgInfo = new ImageInfo(pngChunkIHDR.Cols, pngChunkIHDR.Rows, pngChunkIHDR.Bitspc, alpha, grayscale, palette);
rowb = new byte[ImgInfo.BytesPerRow + 1];
rowbprev = new byte[rowb.Length];
rowbfilter = new byte[rowb.Length];
interlaced = (pngChunkIHDR.Interlaced == 1);
deinterlacer = (interlaced ? new PngDeinterlacer(ImgInfo) : null);
if (pngChunkIHDR.Filmeth != 0 || pngChunkIHDR.Compmeth != 0 || (pngChunkIHDR.Interlaced & 0xFFFE) != 0)
{
throw new PngjInputException("compmethod or filtermethod or interlaced unrecognized");
}
if (pngChunkIHDR.Colormodel < 0 || pngChunkIHDR.Colormodel > 6 || pngChunkIHDR.Colormodel == 1 || pngChunkIHDR.Colormodel == 5)
{
throw new PngjInputException("Invalid colormodel " + pngChunkIHDR.Colormodel.ToString());
}
if (pngChunkIHDR.Bitspc != 1 && pngChunkIHDR.Bitspc != 2 && pngChunkIHDR.Bitspc != 4 && pngChunkIHDR.Bitspc != 8 && pngChunkIHDR.Bitspc != 16)
{
throw new PngjInputException("Invalid bit depth " + pngChunkIHDR.Bitspc.ToString());
}
}
