Show SourceAndConverter

[tischi]

Hi @tpietzsch,

I started working on making it possible to show a SourceAndConverter.

This seems to work:
https://github.com/tischi/bigdataviewer-vistools/blob/displaySourceAndConverter/src/test/java/bdv/util/ExampleSourceAndConverter4D.java#L19

However, it will fail if the converter is not a ColorConverter, see here: #37

I think the solution could be to implement a wrapper like sketched below in net.imglib2.display:

public static class ARGBConverter extends ScaledARGBConverter< ARGBType >
{          
        Converter< ?, ARGBType > converter
		
        public ARGB( final Converter< ?, ARGBType > converter, final double min, final double max )
	{
               this.converter = converter;
 	       super( min, max );
	}

	@Override
	public void convert( final ? input, final ARGBType output )
	{
               converter.convert( input, output );
	       output.set( getScaledColor( output.get() ) );
	}
}

, which would be called in case the provided Converter is not yet a ColorConverter.

What do you think?

[tischi]

To make this PR less complex I, for now, added code that throws an error if the Converter of the SourceAndConverter is not ColorConverter: https://github.com/tischi/bigdataviewer-vistools/blob/16507715f822113a76582ceab98d250774496c9e/src/main/java/bdv/util/BdvFunctions.java#L214

I think this restriction could be removed later by implementing above mentioned changes to net.imglib2.display.

[tpietzsch]

I'm closing this.
In the meantime, BdvFunctions.show(SourceAndConverter, ...) was already added...
I just cherry-picked the ExampleSourceAndConverter4D from this PR (2e0f139).