public virtual string GetColorTypeDescription()
{
int?value = _directory.GetInteger(PngDirectory.TagColorType);
if (value == null)
{
return(null);
}
PngColorType colorType = PngColorType.FromNumericValue((int)value);
if (colorType == null)
{
return(null);
}
return(colorType.GetDescription());
}
public static Metadata ParsePngDirectory(PngDirectory directory, Metadata metadata)
{
if (directory.TryGetInt32(PngDirectory.TagImageWidth, out var width))
{
metadata.Image.Width = width;
}
if (directory.TryGetInt32(PngDirectory.TagImageHeight, out var height))
{
metadata.Image.Height = height;
}
if (directory.TryGetInt32(PngDirectory.TagColorType, out var colorTypeId))
{
var colorType = PngColorType.FromNumericValue(colorTypeId);
metadata.Image.PngColorType = colorType.Description;
int?numberOfComponents = null;
if (colorType == PngColorType.Greyscale)
{
numberOfComponents = 1;
}
else if (colorType == PngColorType.TrueColor)
{
numberOfComponents = 3;
}
else if (colorType == PngColorType.GreyscaleWithAlpha)
{
numberOfComponents = 2;
}
else if (colorType == PngColorType.TrueColorWithAlpha)
{
numberOfComponents = 4;
}
int?dataPrecision = null;
if (directory.TryGetInt32(PngDirectory.TagBitsPerSample, out var bitsPerSample))
{
dataPrecision = bitsPerSample;
}
if (dataPrecision != null)
{
if (numberOfComponents != null)
{
metadata.Image.BitDepth = (int)(numberOfComponents * dataPrecision);
}
else
{
metadata.Image.DataPrecision = (int)dataPrecision;
}
}
}
if (directory.TryGetDouble(PngDirectory.TagGamma, out var gamma))
{
metadata.Image.Gamma = gamma;
}
if (directory.ContainsTag(PngDirectory.TagCompressionType))
{
metadata.Image.CompressionType = directory.GetDescription(PngDirectory.TagCompressionType);
}
if (directory.ContainsTag(PngDirectory.TagInterlaceMethod))
{
metadata.Image.InterlaceMethod = directory.GetDescription(PngDirectory.TagInterlaceMethod);
}
return(metadata);
}
