// AForge Image Processing Library
//
// Copyright © Andrew Kirillov, 2005-2007
// andrew.kirillov@gmail.com
//
// This algorithm was taken from the AForge.NET sourcecodes
// and adopted for the FreeImage library
//
//	Copyright (C) 2007-2008:
//	monday2000	monday2000@yandex.ru

// Resize image using bicubic interpolation

#include "FreeImage.h"
#include "Utilities.h"

////////////////////////////////////////////////////////////////////////////////

double BiCubicKernel(double x)
{
	if ( x > 2.0 )
		return 0.0;
	
	double a, b, c, d;
	double xm1 = x - 1.0;
	double xp1 = x + 1.0;
	double xp2 = x + 2.0;
	
	a = ( xp2 <= 0.0 ) ? 0.0 : xp2 * xp2 * xp2;
	b = ( xp1 <= 0.0 ) ? 0.0 : xp1 * xp1 * xp1;
	c = ( x   <= 0.0 ) ? 0.0 : x * x * x;
	d = ( xm1 <= 0.0 ) ? 0.0 : xm1 * xm1 * xm1;
	
	return ( 0.16666666666666666667 * ( a - ( 4.0 * b ) + ( 6.0 * c ) - ( 4.0 * d ) ) );
}

////////////////////////////////////////////////////////////////////////////////

FIBITMAP* ProcessFilter(FIBITMAP* src_dib, unsigned new_width, unsigned new_height)
{
	// get source image size
	unsigned width = FreeImage_GetWidth(src_dib);
	
	unsigned height = FreeImage_GetHeight(src_dib);
	
	unsigned src_pitch = FreeImage_GetPitch(src_dib);
	
	unsigned bpp = FreeImage_GetBPP(src_dib);
	
	unsigned btpp = bpp/8;
	
	
	FIBITMAP* dst_dib = FreeImage_Allocate(new_width, new_height, bpp);
	
	if(bpp == 8)
	{
		if(FreeImage_GetColorType(src_dib) == FIC_MINISWHITE) {
			// build an inverted greyscale palette
			RGBQUAD *dst_pal = FreeImage_GetPalette(dst_dib);
			for(int i = 0; i < 256; i++) {
				dst_pal[i].rgbRed = dst_pal[i].rgbGreen =
					dst_pal[i].rgbBlue = (BYTE)(255 - i);
			}
		} else {
			// build a greyscale palette
			RGBQUAD *dst_pal = FreeImage_GetPalette(dst_dib);
			for(int i = 0; i < 256; i++) {
				dst_pal[i].rgbRed = dst_pal[i].rgbGreen =
					dst_pal[i].rgbBlue = (BYTE)i;
			}
		}
	}
	
	unsigned dst_pitch = FreeImage_GetPitch(dst_dib);
	
	BYTE* src_bits = (BYTE*)FreeImage_GetBits(src_dib); // The image raster
	
	BYTE* dst_bits = (BYTE*)FreeImage_GetBits(dst_dib); // The image raster
	
	BYTE* linek, *lined;
	
	unsigned d;
	
	
	double xFactor = (double) width / new_width;
	double yFactor = (double) height / new_height;
	
	// coordinates of source points and coefficients
	double  ox, oy, dx, dy, k1, k2;
	int     ox1, oy1, ox2, oy2;
	
	// destination pixel values
	double* p_g = new double[btpp];
	
	// width and height decreased by 1
	int ymax = height - 1;
	int xmax = width - 1;
	
	
	for ( int y = 0; y < new_height; y++ )
	{
		// Y coordinates
		oy  = (double) y * yFactor - 0.5;
		oy1 = (int) oy;
		dy  = oy - (double) oy1;
		
		lined = dst_bits + y * dst_pitch;
		
		for ( int x = 0; x < new_width; x++ )
		{
			// X coordinates
			ox  = (double) x * xFactor - 0.5f;
			ox1 = (int) ox;
			dx  = ox - (double) ox1;
			
			// initial pixel value
			memset(p_g, 0, sizeof(double)*btpp);
			
			for ( int n = -1; n < 3; n++ )
			{
				// get Y coefficient
				k1 = BiCubicKernel( dy - (double) n );
				
				oy2 = oy1 + n;
				if ( oy2 < 0 )
					oy2 = 0;
				if ( oy2 > ymax )
					oy2 = ymax;
				
				linek = src_bits + oy2 * src_pitch;
				
				for ( int m = -1; m < 3; m++ )
				{
					// get X coefficient
					k2 = k1 * BiCubicKernel( (double) m - dx );
					
					ox2 = ox1 + m;
					if ( ox2 < 0 )
						ox2 = 0;
					if ( ox2 > xmax )
						ox2 = xmax;						
					
					for (d=0; d<btpp; d++)
						
						p_g[d] += k2 * linek[ox2 * btpp + d];
				}
			}
			for (d=0; d<btpp; d++)
				
				lined[x * btpp + d] = (BYTE) p_g[d];
		}
	}
	
	// Copying the DPI...
	
	FreeImage_SetDotsPerMeterX(dst_dib, FreeImage_GetDotsPerMeterX(src_dib));
	
	FreeImage_SetDotsPerMeterY(dst_dib, FreeImage_GetDotsPerMeterY(src_dib));
	
	delete [] p_g;
	
	return dst_dib;
}

////////////////////////////////////////////////////////////////////////////////
/**
FreeImage error handler
@param fif Format / Plugin responsible for the error 
@param message Error message
*/
void FreeImageErrorHandler(FREE_IMAGE_FORMAT fif, const char *message) {
	printf("\n*** "); 
	printf("%s Format\n", FreeImage_GetFormatFromFIF(fif));
	printf(message);
	printf(" ***\n");
}

////////////////////////////////////////////////////////////////////////////////

/** Generic image loader

  @param lpszPathName Pointer to the full file name
  @param flag Optional load flag constant
  @return Returns the loaded dib if successful, returns NULL otherwise
*/

FIBITMAP* GenericLoader(const char* lpszPathName, int flag)
{	
	FREE_IMAGE_FORMAT fif = FIF_UNKNOWN;
	// check the file signature and deduce its format
	// (the second argument is currently not used by FreeImage)
	
	fif = FreeImage_GetFileType(lpszPathName, 0);
	
	FIBITMAP* dib;
	
	if(fif == FIF_UNKNOWN)
	{
		// no signature ?
		// try to guess the file format from the file extension
		fif = FreeImage_GetFIFFromFilename(lpszPathName);
	}
	
	// check that the plugin has reading capabilities ...
	if((fif != FIF_UNKNOWN) && FreeImage_FIFSupportsReading(fif))
	{
		// ok, let's load the file
		dib = FreeImage_Load(fif, lpszPathName, flag);
		
		// unless a bad file format, we are done !
		if (!dib)
		{
			printf("%s%s%s\n","File \"", lpszPathName, "\" not found.");
			return NULL;
		}
	}	
	
	return dib;
}

////////////////////////////////////////////////////////////////////////////////

int main(int argc, char *argv[]) {
	
	// call this ONLY when linking with FreeImage as a static library
#ifdef FREEIMAGE_LIB
	FreeImage_Initialise();
#endif // FREEIMAGE_LIB
	
	// initialize your own FreeImage error handler
	
	FreeImage_SetOutputMessage(FreeImageErrorHandler);
	
	if(argc != 3) {
		printf("Usage : res_bic <input_file> <ratio (double)>\n");
		return 0;
	}
	
	FIBITMAP *dib = GenericLoader(argv[1], 0);
	
	double ratio = atof(argv[2]);
	
	unsigned new_width = (unsigned)FreeImage_GetWidth(dib)*ratio;
	
	unsigned new_height = (unsigned)FreeImage_GetHeight(dib)*ratio;	
	
	if (dib)
	{		
		// bitmap is successfully loaded!
		
		if (FreeImage_GetImageType(dib) == FIT_BITMAP)
		{
			if (FreeImage_GetBPP(dib) == 8 || FreeImage_GetBPP(dib) == 24)
			{
				FIBITMAP* dst_dib = ProcessFilter(dib, new_width, new_height);
				
				if (dst_dib)
				{					
					// save the filtered bitmap
					const char *output_filename = "filtered.tif";
					
					// first, check the output format from the file name or file extension
					FREE_IMAGE_FORMAT out_fif = FreeImage_GetFIFFromFilename(output_filename);
					
					if(out_fif != FIF_UNKNOWN)
					{
						// then save the file
						FreeImage_Save(out_fif, dst_dib, output_filename, 0);
					}
					
					// free the loaded FIBITMAP
					FreeImage_Unload(dst_dib);					
				}
			}
			
			else
				
				printf("%s\n", "Unsupported color mode.");
		}
		
		else // non-FIT_BITMAP images are not supported.
			
			printf("%s\n", "Unsupported color mode.");
		
		FreeImage_Unload(dib);
	}	 
	
	// call this ONLY when linking with FreeImage as a static library
#ifdef FREEIMAGE_LIB
	FreeImage_DeInitialise();
#endif // FREEIMAGE_LIB
	
	return 0;
}