| public static WriteBytes ( Stream os, byte b ) : void | ||
| os | Stream | |
| b | byte | |
| return | void | |
/// <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);
}
