text: // ==========================================================
  // Bitmap conversion routines
  //
  // Design and implementation by
  // - Herv?Drolon (drolon@infonie.fr)
  //
  // This file is part of FreeImage 3
  //
  // COVERED CODE IS PROVIDED UNDER THIS LICENSE ON AN "AS IS" BASIS, WITHOUT WARRANTY
  // OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, WITHOUT LIMITATION, WARRANTIES
  // THAT THE COVERED CODE IS FREE OF DEFECTS, MERCHANTABLE, FIT FOR A PARTICULAR PURPOSE
  // OR NON-INFRINGING. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE COVERED
  // CODE IS WITH YOU. SHOULD ANY COVERED CODE PROVE DEFECTIVE IN ANY RESPECT, YOU (NOT
  // THE INITIAL DEVELOPER OR ANY OTHER CONTRIBUTOR) ASSUME THE COST OF ANY NECESSARY
  // SERVICING, REPAIR OR CORRECTION. THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL
  // PART OF THIS LICENSE. NO USE OF ANY COVERED CODE IS AUTHORIZED HEREUNDER EXCEPT UNDER
  // THIS DISCLAIMER.
  //
  // Use at your own risk!
  // ==========================================================
  
  #include "FreeImage.h"
  #include "Utilities.h"
  #include "MemHelper.h"
  
  // ----------------------------------------------------------
  //   smart convert X to Float
  // ----------------------------------------------------------
  
  FIBITMAP * DLL_CALLCONV
  FreeImage_ConvertToFloat(FreeImageMem* mem, FIBITMAP *dib) {
  	FIBITMAP *src = NULL;
  	FIBITMAP *dst = NULL;
  
  	if(!FreeImage_HasPixels(dib)) return NULL;
  
  	FreeImageMem tmem;
  	FreeImage_MakeTempMem(&tmem,mem);
  
  	FREE_IMAGE_TYPE src_type = FreeImage_GetImageType(dib);
  
  	// check for allowed conversions 
  	switch(src_type) {
  		case FIT_BITMAP:
  		{
  			// allow conversion from 8-bit
  			if((FreeImage_GetBPP(dib) == 8) && (FreeImage_GetColorType(dib) == FIC_MINISBLACK)) {
  				src = dib;
  			} else {
  				src = FreeImage_ConvertToGreyscale(&tmem, dib);
  				if(!src) return NULL;
  			}
  			break;
  		}
  		case FIT_UINT16:
  		case FIT_RGB16:
  		case FIT_RGBA16:
  		case FIT_RGBF:
  		case FIT_RGBAF:
  			src = dib;
  			break;
  		case FIT_FLOAT:
  			// float type : clone the src
  			return FreeImage_Clone(mem, dib);
  		default:
  			return NULL;
  	}
  
  	// allocate dst image
  
  	const unsigned width = FreeImage_GetWidth(src);
  	const unsigned height = FreeImage_GetHeight(src);
  
  	dst = FreeImage_AllocateT(mem, FIT_FLOAT, width, height);
  	if(!dst) {
  		if(src != dib) {
  			FreeImage_Unload(&tmem, src);
  		}
  		return NULL;
  	}
  
  	// copy metadata from src to dst
  	FreeImage_CloneMetadata(mem, dst, src);
  
  	// convert from src type to float
  
  	const unsigned src_pitch = FreeImage_GetPitch(src);
  	const unsigned dst_pitch = FreeImage_GetPitch(dst);
  
  	const BYTE *src_bits = (BYTE*)FreeImage_GetBits(src);
  	BYTE *dst_bits = (BYTE*)FreeImage_GetBits(dst);
  
  	switch(src_type) {
  		case FIT_BITMAP:
  		{
  			for(unsigned y = 0; y < height; y++) {
  				const BYTE *src_pixel = (BYTE*)src_bits;
  				float *dst_pixel = (float*)dst_bits;
  				for(unsigned x = 0; x < width; x++) {
  					// convert and scale to the range [0..1]
  					dst_pixel[x] = (float)(src_pixel[x]) / 255;
  				}
  				src_bits += src_pitch;
  				dst_bits += dst_pitch;
  			}
  		}
  		break;
  
  		case FIT_UINT16:
  		{
  			for(unsigned y = 0; y < height; y++) {
  				const WORD *src_pixel = (WORD*)src_bits;
  				float *dst_pixel = (float*)dst_bits;
  
  				for(unsigned x = 0; x < width; x++) {
  					// convert and scale to the range [0..1]
  					dst_pixel[x] = (float)(src_pixel[x]) / 65535;
  				}
  				src_bits += src_pitch;
  				dst_bits += dst_pitch;
  			}
  		}
  		break;
  
  		case FIT_RGB16:
  		{
  			for(unsigned y = 0; y < height; y++) {
  				const FIRGB16 *src_pixel = (FIRGB16*)src_bits;
  				float *dst_pixel = (float*)dst_bits;
  
  				for(unsigned x = 0; x < width; x++) {
  					// convert and scale to the range [0..1]
  					dst_pixel[x] = LUMA_REC709(src_pixel[x].red, src_pixel[x].green, src_pixel[x].blue) / 65535.0F;
  				}
  				src_bits += src_pitch;
  				dst_bits += dst_pitch;
  			}
  		}
  		break;
  
  		case FIT_RGBA16:
  		{
  			for(unsigned y = 0; y < height; y++) {
  				const FIRGBA16 *src_pixel = (FIRGBA16*)src_bits;
  				float *dst_pixel = (float*)dst_bits;
  
  				for(unsigned x = 0; x < width; x++) {
  					// convert and scale to the range [0..1]
  					dst_pixel[x] = LUMA_REC709(src_pixel[x].red, src_pixel[x].green, src_pixel[x].blue) / 65535.0F;
  				}
  				src_bits += src_pitch;
  				dst_bits += dst_pitch;
  			}
  		}
  		break;
  
  		case FIT_RGBF:
  		{
  			for(unsigned y = 0; y < height; y++) {
  				const FIRGBF *src_pixel = (FIRGBF*)src_bits;
  				float *dst_pixel = (float*)dst_bits;
  
  				for(unsigned x = 0; x < width; x++) {
  					// convert (assume pixel values are in the range [0..1])
  					dst_pixel[x] = LUMA_REC709(src_pixel[x].red, src_pixel[x].green, src_pixel[x].blue);
  				}
  				src_bits += src_pitch;
  				dst_bits += dst_pitch;
  			}
  		}
  		break;
  
  		case FIT_RGBAF:
  		{
  			for(unsigned y = 0; y < height; y++) {
  				const FIRGBAF *src_pixel = (FIRGBAF*)src_bits;
  				float *dst_pixel = (float*)dst_bits;
  
  				for(unsigned x = 0; x < width; x++) {
  					// convert (assume pixel values are in the range [0..1])
  					dst_pixel[x] = LUMA_REC709(src_pixel[x].red, src_pixel[x].green, src_pixel[x].blue);
  				}
  				src_bits += src_pitch;
  				dst_bits += dst_pitch;
  			}
  		}
  		break;
  	}
  
  	if(src != dib) {
  		FreeImage_Unload(&tmem, src);
  	}
  
  	return dst;
  }
  
  