/// <summary>
/// Parse the colorspace information from the specified colorspace item.
/// </summary>
/// <param name="colorSpace">The external color space object to parse.</param>
public static PdfColorSpace Parse(PdfItem colorSpace)
{
if (colorSpace == null)
{
throw new ArgumentNullException("colorSpace", "The provided color space was null.");
}
Func <PdfItem, PdfColorSpace> defaultAction = (a) => { throw new Exception(String.Format("An unsupported colorspace '{0}' was provided.", GetColorSpaceName(a))); };
IDictionary <string, Func <PdfItem, PdfColorSpace> > map = new Dictionary <string, Func <PdfItem, PdfColorSpace> > {
// An Indexed color space is defined by a four-element array, as follows:
//
// /Indexed base hival lookup
//
// base - an array or name that identifies the base color space in which the values in the color table are to be interpreted
// hival - an integer that specifies the maximum valid index value. I
// lookup - The color table is defined by the lookup parameter, which can be either a stream or (in PDF 1.2) a string
{ "/Indexed", (a) => {
if (a == null)
{
throw new ArgumentNullException("a", "The indexed colorspace cannot be null.");
}
var array = (a as PdfArray) ?? (a.Get() as PdfArray);
if (array == null)
{
throw new ArgumentException("a", "The indexed colorspace not specified as an array.");
}
PdfItem colorBase = array.Elements[1].Get(); // base
int colors = array.Elements.GetInteger(2); // hival
PdfItem lookup = array.Elements[3]; // lookup
// We currently only support DeviceRGB indexed color spaces.
if ((colorBase.IsName() && ((PdfName)colorBase).Value == "/DeviceRGB"))
{
return(new PdfIndexedRGBColorSpace(lookup, colors));
}
throw new NotImplementedException(String.Format("The indexed colorspace '{0}' is not supported.", GetColorSpaceName(colorBase)));
} },
// Standard RGB Colorspace
{ "/DeviceRGB", (a) => new PdfRGBColorSpace() },
// Gray Colorspace
{ "/DeviceGray", (a) => new PdfGrayColorSpace() },
// Standard CMYK Colorspace
{ "/DeviceCMYK", (a) => {
throw new NotImplementedException("CMYK encoded images are not supported.");
return(new PdfCMYKColorSpace());
} },
};
string name = GetColorSpaceName(colorSpace);
var action = (map.ContainsKey(name) ? map[name] : defaultAction);
return(action.Invoke(colorSpace));
}
/// <summary>
/// Get's the colorspace name for the specified item.
/// </summary>
/// <param name="colorSpace">The colorspace to inspect.</param>
/// <returns>The PdfName of the specified item.</returns>
private static string GetColorSpaceName(PdfItem colorSpace)
{
if (colorSpace == null) return(null);
if (colorSpace.IsArray()) return (GetColorSpaceName(((PdfArray)colorSpace).Elements[0]));
if (colorSpace.IsName()) return (((PdfName) colorSpace).Value);
if (colorSpace.IsReference()) {
PdfReference reference = (colorSpace as PdfReference);
if (reference != null) {
return (GetColorSpaceName(reference.Value));
}
}
return (null);
}
/// <summary>
/// Get's the colorspace name for the specified item.
/// </summary>
/// <param name="colorSpace">The colorspace to inspect.</param>
/// <returns>The PdfName of the specified item.</returns>
private static string GetColorSpaceName(PdfItem colorSpace)
{
if (colorSpace == null) return(null);
if (colorSpace.IsArray()) return (GetColorSpaceName(((PdfArray)colorSpace).Elements[0]));
if (colorSpace.IsName()) return (((PdfName) colorSpace).Value);
if (colorSpace.IsReference()) {
PdfReference reference = (colorSpace as PdfReference);
if (reference != null) {
return (GetColorSpaceName(reference.Value));
}
}
return (null);
}
