package de.desy.video.sw;
   
   /**
   * <code>CColorLookupTable</code> creates, prepares and maintains a false colour table 
   * necessary to decode pure grayscale image data to true colour display. Three false colour
   * tables (mappings) are supported at the moment:
   * <ul>
   * <li>PITZ false colour (was invented at PITZ Video System v2, Velizar Miltchev)
   * <li>MATLAB jet false colour (taken from Matlab)
  * <li>GRAYSCALE simple grayscale conversion 
  * </ul>
  * 
  * An important criteria to mention is that these mappings support scaling to physical and 
  * effective bits per pixel settings. For example if source grayscale data is 16bpp physically 
  * encoded (for performance reason) but only 12 of these bits are effectively used, the false 
  * colour table is designed to support 0 as darkest and 4195 (12 bit max) as brightest value. 
  * All other value (for 16 bit: 4096 to 65535) are encoded in magenta to easily detect them as 
  * being illegal. In comparison to that, the output format is always java TYPE_INT_ARGB for 
  * sake of simplicity.<br>
  * The main use is to generate a 1-dimensional false-colour-mapping table that accepts as 
  * index any physically valid grayscale number and returns the matched pixel ready for being
  * placed to the output drawing buffer.    
  *    
  * @author <a href="mailto:stefan.weisse@desy.de">Stefan Weisse</a>
  * @version $Id: Templates.xml,v 1.10 2008/06/20 16:31:13 sweisse Exp $
  *
  */
  
  public final class CColorLookupTable 
  {
  	/**
  	 * array for currently used false colour mapping table 
  	 */
  	private int [] m_ColorLookupTable=null;
  	/**
  	 * buffer currently used false colour mode inside (caching)
  	 */
  	private int m_iColorMode = FALSEPITZ;
  	/**
  	 * buffer currently used maximum number of colours inside (caching), reflects
  	 * bytes per pixel setting (1 => 255, 2 => 65535, 3 => 16777215)
  	 */
  	private int m_iCurMaxColors=0;
  	/**
  	 * buffer currently used effective bits per pixel inside (caching)
  	 */
  	private int m_iEBitPP = 0;
  		
  	/** grayscale mode id */
  	public static final int GRAYSCALE=1;
  	/** PITZ false colour mode id */
  	public static final int FALSEPITZ=2;
  	/** MATLAB JET false colour mode id */
  	public static final int FALSEJET=3;		
  	
  	/**
  	 * initializes default false colour table (1 byte per pixel, 8 effective bits, 
  	 * PITZ false colour) 
  	 * 
  	 */
  	public CColorLookupTable()
  	{
  		AdjustTable( FALSEPITZ, 1, 8);
  	}
  
  	/**
  	 * user code can obtain a reference to the internal memory buffer that contains 
  	 * the current false colour mapping
  	 * 
  	 * @return reference to internal memory buffer
  	 */
  	public int[] getColorLookupTable()
  	{
  		return m_ColorLookupTable;		
  	}
  
  	/**
  	 *  performs recalculation of the mapped false colour table in case the parameters have
  	 *  been changed. If no parameters change in between, nothing is done for sake of caching.
  	 *  
  	 *  @param aMode false colour mode CColorLookupTable.GRAYSCALE, CColorLookupTable.FALSEPITZ 
  	 *  or CColorLookupTable.FALSEJET
  	 *  @param aByPP bytes per pixel setting for new table to calculate 
  	 *  (allowed values are 1, 2, 3)
  	 *  @param aEBitPP effective bits per pixel setting (effective bits must fit inside 
  	 *  bytes per pixel)
  	 *  @return true  mapping table recalculated<br>
  	 *          false mapping table not recalculated (parameters have not changed)
  	 *          
  	 */
  	public boolean AdjustTable( int aMode, int aByPP, int aEBitPP)
  	{
  		int numColors = aByPP << 8;
  		
  		if ((m_iCurMaxColors != numColors) || (m_iEBitPP != aEBitPP) || (aMode != m_iColorMode))
  		{
  			// update private class variables	
  			m_iCurMaxColors = numColors;
  			m_iEBitPP = aEBitPP;
 			m_iColorMode = aMode;
 			m_ColorLookupTable = new int[1 << (aByPP*8)];
     			
 			if (m_iColorMode == FALSEPITZ) 
 				fillColorLookupTablePITZFalseColors();
 			else if (m_iColorMode == FALSEJET)
 				fillColorLookupTableJETFalseColors();
 			else 
 				fillColorLookupTableGrayscale();
 
     		// fill left colours (if effective bpp < physical bpp)
     		// with magenta for easy spotting of illegal values
     		int maxval = 1 << aEBitPP;
     		int maxval_total = 1 << (aByPP*8);
     		int left = maxval_total-maxval;
 
     		if (left > 0)
     		{
     			try 
     			{
     			for (int i=0;i<left;i++)
     			{
     				// put magenta for bad colors that must not happen!
     				// 	alpha24 Red16 Green8 Blue
     				m_ColorLookupTable[i+maxval] = (255 << 24) | (255 << 16) | (255);
     			}
     			}
     			catch( ArrayIndexOutOfBoundsException ex) {}
     			
     		}
     		
     		return true;
 		}
 		return false;
 	}
 	
 	/* no_java_doc
 	 * 
 	 * fills the lookup table using PITZ false colours based on current private class
 	 * variables 
 	 */
 	private void fillColorLookupTablePITZFalseColors()
 	{
 		// fill in PITZ false colors
 
 		int dec = (int) (1 << m_iEBitPP);
 		double decdbl = (double) dec;
 		int i;
 
 		// 	alpha24 Red16 Green8 Blue
 		m_ColorLookupTable[0] = (255 << 24); // black 0-0-0
 
 		// 	alpha24 Red16 Green8 Blue // white 255-255-255
 		m_ColorLookupTable[dec-1] = (255 << 24) | (255 << 16) | (255 << 8) | (255); 
 		
 		int step1min = 1;
 		int step1max = (int) (decdbl/3);
 		
 		int step2min = step1max + 1;
 		int step2max = (int) ((decdbl*293)/500);
 		
 		int step3min = step2max + 1;
 		int step3max = (int) ((decdbl*2)/3);
 		
 		int step4min = step3max + 1;
 		int step4max = (int) decdbl-1;
 
 		for (i=step1min;i<step2min;i++)
 		{
 			double m = -0.5608 / (dec/3-1.0);
 			double n = 1.0 - m*1.0;
 
 			m_ColorLookupTable[i] = (255 << 24) | ((int)((m*i+n)*255.0));
 		}
 
 		for (i=step2min;i<step3min;i++)
 		{
 			double m1= 0.561 / ( (dec*293/500)-(dec/3));
 			double n1 = 0.263 - (m1 * (dec/3));
 		
 			double m2= -0.4314 / ( (dec*293/500)-(dec/3));
 			double n2 = 0 - (m2 * (dec*293/500));
 
 			//	alpha24 Red16 Green8 Blue
 			m_ColorLookupTable[i] = (255 << 24) | (((int)((m1*i+n1)*255.0))<<8) | ((int)((m2*i+n2)*255.0));
 		}
 
 		for (i=step3min;i<step4min;i++)
 		{
 			double m1= 0.176 / ( (dec*2/3)-(dec*293/500));
 			double n1 = 1 - (m1 * (dec*2/3));
 
 			m_ColorLookupTable[i] = (255 << 24) | (((int)((m1*i+n1)*255.0))<<8);
 		}
 		
 		for (i=step4min;i<step4max;i++)
 		{
 			double m1= 0.737 / (dec-(dec*2/3));
 			double n1 = 1 - (m1 * dec);
 
 			m_ColorLookupTable[i] = (255 << 24) | (((int)((m1*i+n1)*255.0))<<16);
 		}
 		
 	}
 	
 	
 	/* no_java_doc
 	 * 
 	 * fills the lookup table using MATLAB Jet false colours based on current private class
 	 * variables
 	 *  
 	 */
 	private void fillColorLookupTableJETFalseColors()
 	{
 		int dec = (int) (1 << m_iEBitPP);
 		int i;
 		
 		int step1min = 0;
 		int step1max = (int) ((dec/8)-1);
 		
 		int step2min = step1max + 1;
 		int step2max = (int) (((dec*3)/8)-1);
 		
 		int step3min = step2max + 1;
 		int step3max = (int) (((dec*5)/8)-1);
 		
 		int step4min = step3max + 1;
 		int step4max = (int) (((dec*7)/8)-1);
 		
 		int step5min = step4max + 1;
 		int step5max = (int) (dec-1);
 
 		// 	alpha24 Red16 Green8 Blue // white 255-255-255
 		m_ColorLookupTable[dec-1] = (255 << 24) | (255 << 16) | (255 << 8) | (255);
 
 		double Dstep2min = (double) step2min;
 		
 		for (i=step1min;i<step2min;i++)
 		{
 			double Di= (double) i;
 			double blue = (((Di/2.0)/Dstep2min)+0.5)*255.0;
 
 			// 	alpha24 Red16 Green8 Blue			
 			m_ColorLookupTable[i] = (255 << 24) | (int) blue;
 		}
 
 		for (i=step2min;i<step3min;i++)
 		{
 			double Di = (double) i;
 			double green = ((Di/(Dstep2min*2.0))-0.5)*255.0;
 			
 			// alpha24 Red16 Green8 Blue
 			m_ColorLookupTable[i] = (255 << 24) | (((int)green)<<8) | 255;
 		}
 
 		for (i=step3min;i<step4min;i++)
 		{
 			double Di = (double) i;
 			double red = ((Di/(Dstep2min*2.0))-1.5) *255.0;
 			double blue = ((1.0-((Di/(Dstep2min*2.0))-1.5))*255.0);
 			
 			// alpha24 Red16 Green8 Blue
 			m_ColorLookupTable[i] = (255 << 24) | (((int)red)<<16) | (255<<8) | ((int) blue);
 		}
 		
 		for (i=step4min;i<step5min;i++)
 		{
 			double Di = (double) i;
 			double green = (((Di/(-(Dstep2min*2.0)))+3.5) *255.0);
 
 			// alpha24 Red16 Green8 Blue
 			m_ColorLookupTable[i] = (255 << 24) | (255<<16) | (((int)green)<<8);
 		}
 
 		for (i=step5min;i<step5max;i++)
 		{
 			double Di = (double) i;
 			double red = (((Di/(-(Dstep2min*2.0)))+4.5) *255.0); 
 
 			// alpha24 Red16 Green8 Blue			
 			m_ColorLookupTable[i] = (255 << 24) | (((int)red)<<16);
 		}
 		
 	}
 
 	
 	/* no_java_doc
 	 * 
 	 * fills the lookup table using grayscales based on current private class
 	 * variables
 	 * 
 	 */
 	private void fillColorLookupTableGrayscale()
 	{
 		int maxval = (int) (1 << m_iEBitPP);
 		
 		try 
 		{
 		for (int i=0;i<maxval;i++)
 		{
 			int gray = (int) ((255.0*i)/maxval);
 			// 	alpha24 Green16 Red8 Blue
 			m_ColorLookupTable[i] = (255 << 24) | (gray << 16) | (gray << 8) | (gray);
 		}
 		}
 		catch( ArrayIndexOutOfBoundsException ex) {}
 		
 	}	
 }