// ==========================================================

// Bitmap conversion routines

//

// Design and implementation by

// - Hervé 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"

// ----------------------------------------------------------

//   smart convert X to RGBF

// ----------------------------------------------------------

FIBITMAP * DLL_CALLCONV

FreeImage_ConvertToRGBF(FIBITMAP *dib) {

  FIBITMAP *src = NULL;

  FIBITMAP *dst = NULL;

  if(!FreeImage_HasPixels(dib)) return NULL;

  const FREE_IMAGE_TYPE src_type = FreeImage_GetImageType(dib);

  // check for allowed conversions 

  switch(src_type) {

    case FIT_BITMAP:

    {

      // allow conversion from 24- and 32-bit

      const FREE_IMAGE_COLOR_TYPE color_type = FreeImage_GetColorType(dib);

      if((color_type != FIC_RGB) && (color_type != FIC_RGBALPHA)) {

        src = FreeImage_ConvertTo24Bits(dib);

        if(!src) return NULL;

      } else {

        src = dib;

      }

      break;

    }

    case FIT_UINT16:

      // allow conversion from 16-bit

      src = dib;

      break;

    case FIT_RGB16:

      // allow conversion from 48-bit RGB

      src = dib;

      break;

    case FIT_RGBA16:

      // allow conversion from 64-bit RGBA (ignore the alpha channel)

      src = dib;

      break;

    case FIT_FLOAT:

      // allow conversion from 32-bit float

      src = dib;

      break;

    case FIT_RGBAF:

      // allow conversion from 128-bit RGBAF

      src = dib;

      break;

    case FIT_RGBF:

      // RGBF type : clone the src

      return FreeImage_Clone(dib);

      break;

    default:

      return NULL;

  }

  // allocate dst image

  const unsigned width = FreeImage_GetWidth(src);

  const unsigned height = FreeImage_GetHeight(src);

  dst = FreeImage_AllocateT(FIT_RGBF, width, height);

  if(!dst) {

    if(src != dib) {

      FreeImage_Unload(src);

    }

    return NULL;

  }

  // copy metadata from src to dst

  FreeImage_CloneMetadata(dst, src);

  // convert from src type to RGBF

  const unsigned src_pitch = FreeImage_GetPitch(src);

  const unsigned dst_pitch = FreeImage_GetPitch(dst);

  switch(src_type) {

    case FIT_BITMAP:

    {

      // calculate the number of bytes per pixel (3 for 24-bit or 4 for 32-bit)

      const unsigned bytespp = FreeImage_GetLine(src) / FreeImage_GetWidth(src);

      const BYTE *src_bits = (BYTE*)FreeImage_GetBits(src);

      BYTE *dst_bits = (BYTE*)FreeImage_GetBits(dst);

      for(unsigned y = 0; y < height; y++) {

        const BYTE   *src_pixel = (BYTE*)src_bits;

        FIRGBF *dst_pixel = (FIRGBF*)dst_bits;

        for(unsigned x = 0; x < width; x++) {

          // convert and scale to the range [0..1]

          dst_pixel->red   = (float)(src_pixel[FI_RGBA_RED])   / 255.0F;

          dst_pixel->green = (float)(src_pixel[FI_RGBA_GREEN]) / 255.0F;

          dst_pixel->blue  = (float)(src_pixel[FI_RGBA_BLUE])  / 255.0F;

          src_pixel += bytespp;

          dst_pixel ++;

        }

        src_bits += src_pitch;

        dst_bits += dst_pitch;

      }

    }

    break;

    case FIT_UINT16:

    {

      const BYTE *src_bits = (BYTE*)FreeImage_GetBits(src);

      BYTE *dst_bits = (BYTE*)FreeImage_GetBits(dst);

      for(unsigned y = 0; y < height; y++) {

        const WORD *src_pixel = (WORD*)src_bits;

        FIRGBF *dst_pixel = (FIRGBF*)dst_bits;

        for(unsigned x = 0; x < width; x++) {

          // convert and scale to the range [0..1]

          const float dst_value = (float)src_pixel[x] / 65535.0F;

          dst_pixel[x].red   = dst_value;

          dst_pixel[x].green = dst_value;

          dst_pixel[x].blue  = dst_value;

        }

        src_bits += src_pitch;

        dst_bits += dst_pitch;

      }

    }

    break;

    case FIT_RGB16:

    {

      const BYTE *src_bits = (BYTE*)FreeImage_GetBits(src);

      BYTE *dst_bits = (BYTE*)FreeImage_GetBits(dst);

      for(unsigned y = 0; y < height; y++) {

        const FIRGB16 *src_pixel = (FIRGB16*) src_bits;

        FIRGBF  *dst_pixel = (FIRGBF*)  dst_bits;

        for(unsigned x = 0; x < width; x++) {

          // convert and scale to the range [0..1]

          dst_pixel[x].red   = (float)(src_pixel[x].red)   / 65535.0F;

          dst_pixel[x].green = (float)(src_pixel[x].green) / 65535.0F;

          dst_pixel[x].blue  = (float)(src_pixel[x].blue)  / 65535.0F;

        }

        src_bits += src_pitch;

        dst_bits += dst_pitch;

      }

    }

    break;

    case FIT_RGBA16:

    {

      const BYTE *src_bits = (BYTE*)FreeImage_GetBits(src);

      BYTE *dst_bits = (BYTE*)FreeImage_GetBits(dst);

      for(unsigned y = 0; y < height; y++) {

        const FIRGBA16 *src_pixel = (FIRGBA16*) src_bits;

        FIRGBF  *dst_pixel = (FIRGBF*)  dst_bits;

        for(unsigned x = 0; x < width; x++) {

          // convert and scale to the range [0..1]

          dst_pixel[x].red   = (float)(src_pixel[x].red)   / 65535.0F;

          dst_pixel[x].green = (float)(src_pixel[x].green) / 65535.0F;

          dst_pixel[x].blue  = (float)(src_pixel[x].blue)  / 65535.0F;

        }

        src_bits += src_pitch;

        dst_bits += dst_pitch;

      }

    }

    break;

    case FIT_FLOAT:

    {

      const BYTE *src_bits = (BYTE*)FreeImage_GetBits(src);

      BYTE *dst_bits = (BYTE*)FreeImage_GetBits(dst);

      for(unsigned y = 0; y < height; y++) {

        const float *src_pixel = (float*) src_bits;

        FIRGBF  *dst_pixel = (FIRGBF*)  dst_bits;

        for(unsigned x = 0; x < width; x++) {

          // convert by copying greyscale channel to each R, G, B channels

          // assume float values are in [0..1]

          const float value = CLAMP(src_pixel[x], 0.0F, 1.0F);

          dst_pixel[x].red   = value;

          dst_pixel[x].green = value;

          dst_pixel[x].blue  = value;

        }

        src_bits += src_pitch;

        dst_bits += dst_pitch;

      }

    }

    break;

    case FIT_RGBAF:

    {

      const BYTE *src_bits = (BYTE*)FreeImage_GetBits(src);

      BYTE *dst_bits = (BYTE*)FreeImage_GetBits(dst);

      for(unsigned y = 0; y < height; y++) {

        const FIRGBAF *src_pixel = (FIRGBAF*) src_bits;

        FIRGBF  *dst_pixel = (FIRGBF*)  dst_bits;

        for(unsigned x = 0; x < width; x++) {

          // convert and skip alpha channel

          dst_pixel[x].red   = CLAMP(src_pixel[x].red, 0.0F, 1.0F);

          dst_pixel[x].green = CLAMP(src_pixel[x].green, 0.0F, 1.0F);

          dst_pixel[x].blue  = CLAMP(src_pixel[x].blue, 0.0F, 1.0F);

        }

        src_bits += src_pitch;

        dst_bits += dst_pitch;

      }

    }

    break;

  }

  if(src != dib) {

    FreeImage_Unload(src);

  }

  return dst;

}