/*
 *  RImageFromPPM.cpp
 *  FaceCrop
 *
 *  Created by Andrew Salamon on 10/12/06.
 *  Copyright 2006 Machine Perception Laboratory, University of California San Diego.. All rights reserved.
 *
 */

#include "RImageFromPPM.h"

extern "C" {
#include <pam.h>
}

inline float grayFromRGB( unsigned long r, unsigned long g, unsigned long b )
{	
	int theGrayValue = ((306 * (r & 0xff)) +
						(601 * (g & 0xff)) +
						(117 * (b & 0xff))) >> 10;
	
	return ((float)theGrayValue) / 255.0;
}

bool restoreRimageFromPPM( RImage<float> &rimage, const std::string &path )
{
	struct pam inpam;
	unsigned int row;
	
	//	pnm_init(&argc, argv);
	
	FILE *imagePtr = pm_openr( path.c_str() );
	if( !imagePtr )
		return false;
	
	pnm_readpaminit( imagePtr, &inpam, PAM_STRUCT_SIZE(tuple_type));
	
	pm_close( imagePtr );

	if( inpam.depth < 3 )
		return false;
	
	rimage.setSize( inpam.width, inpam.height );
		
	tuple *tuplerow = pnm_allocpamrow(&inpam);
	
	unsigned int ridx = 0;
	for (row = 0; row < inpam.height; row++)
	{
		unsigned int column;
		pnm_readpamrow( &inpam, tuplerow );
		for (column = 0; column < inpam.width; ++column)
		{
			rimage.array[ ridx++ ] = grayFromRGB( tuplerow[column][PAM_RED_PLANE], tuplerow[column][PAM_GRN_PLANE], tuplerow[column][PAM_BLU_PLANE] );
		}
	}
	
	pnm_freepamrow(tuplerow);
	
	return true;
}