docs: public static void savePPM(Planar<GrayU8> rgb , String fileName , GrowQueue_I8 temp ) throws IOException {
  		File out = new File(fileName);
  		DataOutputStream os = new DataOutputStream(new FileOutputStream(out));
  
  		String header = String.format("P6\n%d %d\n255\n", rgb.width, rgb.height);
  		os.write(header.getBytes());
  
  		if( temp == null )
  			temp = new GrowQueue_I8();
  		temp.resize(rgb.width*rgb.height*3);
  		byte data[] = temp.data;
  
  		GrayU8 band0 = rgb.getBand(0);
  		GrayU8 band1 = rgb.getBand(1);
  		GrayU8 band2 = rgb.getBand(2);
  
  		int indexOut = 0;
  		for( int y = 0; y < rgb.height; y++ ) {
  			int index = rgb.startIndex + y*rgb.stride;
  			for( int x = 0; x < rgb.width; x++ , index++) {
  				data[indexOut++] = band0.data[index];
  				data[indexOut++] = band1.data[index];
  				data[indexOut++] = band2.data[index];
  			}
  		}
  
  		os.write(data,0,temp.size);
  
  		os.close();
  	}