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

// Bitmap conversion routines

//

// Design and implementation by

// - Floris van den Berg (flvdberg@wxs.nl)

// - Hervé Drolon (drolon@infonie.fr)

// - Jani Kajala (janik@remedy.fi)

//

// 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"

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

#define RGB555(b, g, r) ((((b) >> 3) << FI16_555_BLUE_SHIFT) | (((g) >> 3) << FI16_555_GREEN_SHIFT) | (((r) >> 3) << FI16_555_RED_SHIFT))

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

//  internal conversions X to 16 bits (555)

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

void DLL_CALLCONV

FreeImage_ConvertLine1To16_555(BYTE *target, BYTE *source, int width_in_pixels, RGBQUAD *palette) {

  WORD *new_bits = (WORD *)target;

  for (int cols = 0; cols < width_in_pixels; cols++) {

    int index = (source[cols >> 3] & (0x80 >> (cols & 0x07))) != 0 ? 1 : 0;

    new_bits[cols] = RGB555(palette[index].rgbBlue, palette[index].rgbGreen, palette[index].rgbRed);

  }

}

void DLL_CALLCONV

FreeImage_ConvertLine4To16_555(BYTE *target, BYTE *source, int width_in_pixels, RGBQUAD *palette) {

  WORD *new_bits = (WORD *)target;

  BOOL lonibble = FALSE;

  int x = 0;

  for (int cols = 0; cols < width_in_pixels; cols++) {

    RGBQUAD *grab_palette;

    if (lonibble) {

      grab_palette = palette + LOWNIBBLE(source[x++]);

    } else {

      grab_palette = palette + (HINIBBLE(source[x]) >> 4);                

    }

    new_bits[cols] = RGB555(grab_palette->rgbBlue, grab_palette->rgbGreen, grab_palette->rgbRed);

    lonibble = !lonibble;

  }

}

void DLL_CALLCONV

FreeImage_ConvertLine8To16_555(BYTE *target, BYTE *source, int width_in_pixels, RGBQUAD *palette) {

  WORD *new_bits = (WORD *)target;

  for (int cols = 0; cols < width_in_pixels; cols++) {

    RGBQUAD *grab_palette = palette + source[cols];

    new_bits[cols] = RGB555(grab_palette->rgbBlue, grab_palette->rgbGreen, grab_palette->rgbRed);

  }

}

void DLL_CALLCONV

FreeImage_ConvertLine16_565_To16_555(BYTE *target, BYTE *source, int width_in_pixels) {

  WORD *src_bits = (WORD *)source;

  WORD *new_bits = (WORD *)target;

  for (int cols = 0; cols < width_in_pixels; cols++) {

    new_bits[cols] = RGB555((((src_bits[cols] & FI16_565_BLUE_MASK) >> FI16_565_BLUE_SHIFT) * 0xFF) / 0x1F,

                          (((src_bits[cols] & FI16_565_GREEN_MASK) >> FI16_565_GREEN_SHIFT) * 0xFF) / 0x3F,

                (((src_bits[cols] & FI16_565_RED_MASK) >> FI16_565_RED_SHIFT) * 0xFF) / 0x1F);

  }

}

void DLL_CALLCONV

FreeImage_ConvertLine24To16_555(BYTE *target, BYTE *source, int width_in_pixels) {

  WORD *new_bits = (WORD *)target;

  for (int cols = 0; cols < width_in_pixels; cols++) {

    new_bits[cols] = RGB555(source[FI_RGBA_BLUE], source[FI_RGBA_GREEN], source[FI_RGBA_RED]);

    source += 3;

  }

}

void DLL_CALLCONV

FreeImage_ConvertLine32To16_555(BYTE *target, BYTE *source, int width_in_pixels) {

  WORD *new_bits = (WORD *)target;

  for (int cols = 0; cols < width_in_pixels; cols++) {

    new_bits[cols] = RGB555(source[FI_RGBA_BLUE], source[FI_RGBA_GREEN], source[FI_RGBA_RED]);

    source += 4;

  }

}

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

//   smart convert X to 16 bits

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

FIBITMAP * DLL_CALLCONV

FreeImage_ConvertTo16Bits555(FIBITMAP *dib) {

  if(!FreeImage_HasPixels(dib) || (FreeImage_GetImageType(dib) != FIT_BITMAP)) return NULL;

  const int width = FreeImage_GetWidth(dib);

  const int height = FreeImage_GetHeight(dib);

  const int bpp = FreeImage_GetBPP(dib);

  if(bpp == 16) {

    if ((FreeImage_GetRedMask(dib) == FI16_565_RED_MASK) && (FreeImage_GetGreenMask(dib) == FI16_565_GREEN_MASK) && (FreeImage_GetBlueMask(dib) == FI16_565_BLUE_MASK)) {

      // RGB 565

      FIBITMAP *new_dib = FreeImage_Allocate(width, height, 16, FI16_555_RED_MASK, FI16_555_GREEN_MASK, FI16_555_BLUE_MASK);

      if(new_dib == NULL) {

        return NULL;

      }

      for (int rows = 0; rows < height; rows++) {

        FreeImage_ConvertLine16_565_To16_555(FreeImage_GetScanLine(new_dib, rows), FreeImage_GetScanLine(dib, rows), width);

      }

      // copy metadata from src to dst

      FreeImage_CloneMetadata(new_dib, dib);

      return new_dib;

    } else {

      // RGB 555

      return FreeImage_Clone(dib);

    }

  }

  else {

    // other bpp cases => convert to RGB 555

    FIBITMAP *new_dib = FreeImage_Allocate(width, height, 16, FI16_555_RED_MASK, FI16_555_GREEN_MASK, FI16_555_BLUE_MASK);

    if(new_dib == NULL) {

      return NULL;

    }

    // copy metadata from src to dst

    FreeImage_CloneMetadata(new_dib, dib);

    switch (bpp) {

      case 1 :

      {

        for (int rows = 0; rows < height; rows++) {

          FreeImage_ConvertLine1To16_555(FreeImage_GetScanLine(new_dib, rows), FreeImage_GetScanLine(dib, rows), width, FreeImage_GetPalette(dib));

        }

        return new_dib;

      }

      case 4 :

      {

        for (int rows = 0; rows < height; rows++) {

          FreeImage_ConvertLine4To16_555(FreeImage_GetScanLine(new_dib, rows), FreeImage_GetScanLine(dib, rows), width, FreeImage_GetPalette(dib));

        }

        return new_dib;

      }

      case 8 :

      {

        for (int rows = 0; rows < height; rows++) {

          FreeImage_ConvertLine8To16_555(FreeImage_GetScanLine(new_dib, rows), FreeImage_GetScanLine(dib, rows), width, FreeImage_GetPalette(dib));

        }

        return new_dib;

      }

      case 24 :

      {

        for (int rows = 0; rows < height; rows++) {

          FreeImage_ConvertLine24To16_555(FreeImage_GetScanLine(new_dib, rows), FreeImage_GetScanLine(dib, rows), width);

        }

        return new_dib;

      }

      case 32 :

      {

        for (int rows = 0; rows < height; rows++) {

          FreeImage_ConvertLine32To16_555(FreeImage_GetScanLine(new_dib, rows), FreeImage_GetScanLine(dib, rows), width);

        }

        return new_dib;

      }

      default :

        // unreachable code ...

        FreeImage_Unload(new_dib);

        break;

    }

  }

  return NULL;

}