Method readChannel

src/IECoreImage/ImageReader.cpp:324–388

		}

		DataPtr readChannel( const std::string &name, bool raw )
		{
			open( /* throwOnFailure */ true );

			const ImageSpec *spec = m_cache->imagespec( m_inputFileName, /* subimage = */ 0, miplevel() );

			const auto channelIt = find( spec->channelnames.begin(), spec->channelnames.end(), name );
			if( channelIt == spec->channelnames.end() )
			{
				throw InvalidArgumentException( "Image Reader : Non-existent image channel \"" + name + "\" requested." );
			}

			size_t channelIndex = channelIt - spec->channelnames.begin();

			if( raw )
			{
				switch( spec->format.basetype )
				{
					case TypeDesc::UCHAR :
					{
						return readTypedChannel<unsigned char>( channelIndex, spec->format );
					}
					case TypeDesc::CHAR :
					{
						return readTypedChannel<char>( channelIndex, spec->format );
					}
					case TypeDesc::USHORT :
					{
						return readTypedChannel<unsigned short>( channelIndex, spec->format );
					}
					case TypeDesc::SHORT :
					{
						return readTypedChannel<short>( channelIndex, spec->format );
					}
					case TypeDesc::UINT :
					{
						return readTypedChannel<unsigned int>( channelIndex, spec->format );
					}
					case TypeDesc::INT :
					{
						return readTypedChannel<int>( channelIndex, spec->format );
					}
					case TypeDesc::HALF :
					{
						return readTypedChannel<half>( channelIndex, spec->format );
					}
					case TypeDesc::FLOAT :
					{
						return readTypedChannel<float>( channelIndex, spec->format );
					}
					case TypeDesc::DOUBLE :
					{
						return readTypedChannel<double>( channelIndex, spec->format );
					}
					default :
					{
						throw IECore::IOException( ( boost::format( "ImageReader : Unsupported data type \"%d\"" ) % spec->format ).str() );
					}