private void WriteImageGamma()
{
using (var chunk = new PngChunkStream(output, PngChunkIdentifier.ImageGamma))
{
chunk.WriteBigEndian(45455);
}
}
private void WriteTextualData(string key, string value)
{
using (var chunk = new PngChunkStream(output, PngChunkIdentifier.TextualData))
{
chunk.Write(key);
chunk.WriteByte(0);
chunk.Write(value);
}
}
private void WriteTransparency()
{
if (palette.Count == 0 || !palette.HasAlphaChannel)
{
return;
}
using (var chunk = new PngChunkStream(output, PngChunkIdentifier.Transparency))
{
for (var i = 0; i < palette.Count; i++)
{
chunk.WriteByte((byte)palette[i].A);
}
}
}
private void WriteImageHeader()
{
using (var chunk = new PngChunkStream(output, PngChunkIdentifier.ImageHeader))
{
var colorType = palette.Count > 0 ?
PngColorType.IndexedColour : PngColorType.TruecolourWithAlpha;
chunk.WriteBigEndian(Width);
chunk.WriteBigEndian(Height);
chunk.WriteByte(8); // Bit depth
chunk.WriteByte(colorType);
chunk.WriteByte(0); // Compression
chunk.WriteByte(0); // Filter
chunk.WriteByte(0); // Interlace
}
}
private void WriteImageData()
{
using (var chunk = new PngChunkStream(output, PngChunkIdentifier.ImageData))
{
using (var deflate = new ZlibStream(chunk))
{
if (palette.Count > 0)
{
WriteIndexed(deflate);
}
else
{
WriteTrueColorWithAlpha(deflate);
}
}
}
}
private void WritePalette()
{
if (palette.Count == 0)
{
return;
}
using (var chunk = new PngChunkStream(output, PngChunkIdentifier.Palette))
{
for (var i = 0; i < palette.Count; i++)
{
chunk.WriteByte((byte)palette[i].R);
chunk.WriteByte((byte)palette[i].G);
chunk.WriteByte((byte)palette[i].B);
}
}
}
