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

// Bitmap conversion routines

//

// Design and implementation by

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

// - Hervé Drolon (drolon@infonie.fr)

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

// - Karl-Heinz Bussian (khbussian@moss.de)

// - Carsten Klein (cklein05@users.sourceforge.net)

//

// 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"

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

//  internal conversions X to 8 bits

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

void DLL_CALLCONV

FreeImage_ConvertLine1To8(BYTE *target, BYTE *source, int width_in_pixels) {

  for (unsigned cols = 0; cols < (unsigned)width_in_pixels; cols++)

    target[cols] = (source[cols >> 3] & (0x80 >> (cols & 0x07))) != 0 ? 255 : 0; 

}

void DLL_CALLCONV

FreeImage_ConvertLine4To8(BYTE *target, BYTE *source, int width_in_pixels) {

  unsigned count_new = 0;

  unsigned count_org = 0;

  BOOL hinibble = TRUE;

  while (count_new < (unsigned)width_in_pixels) {

    if (hinibble) {

      target[count_new] = (source[count_org] >> 4);

    } else {

      target[count_new] = (source[count_org] & 0x0F);

      count_org++;

    }

    hinibble = !hinibble;

    count_new++;

  }

}

void DLL_CALLCONV

FreeImage_ConvertLine16To8_555(BYTE *target, BYTE *source, int width_in_pixels) {

  const WORD *const bits = (WORD *)source;

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

    target[cols] = GREY((((bits[cols] & FI16_555_RED_MASK) >> FI16_555_RED_SHIFT) * 0xFF) / 0x1F,

                      (((bits[cols] & FI16_555_GREEN_MASK) >> FI16_555_GREEN_SHIFT) * 0xFF) / 0x1F,

              (((bits[cols] & FI16_555_BLUE_MASK) >> FI16_555_BLUE_SHIFT) * 0xFF) / 0x1F);

  }

}

void DLL_CALLCONV

FreeImage_ConvertLine16To8_565(BYTE *target, BYTE *source, int width_in_pixels) {

  const WORD *const bits = (WORD *)source;

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

    target[cols] = GREY((((bits[cols] & FI16_565_RED_MASK) >> FI16_565_RED_SHIFT) * 0xFF) / 0x1F,

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

          (((bits[cols] & FI16_565_BLUE_MASK) >> FI16_565_BLUE_SHIFT) * 0xFF) / 0x1F);

  }

}

void DLL_CALLCONV

FreeImage_ConvertLine24To8(BYTE *target, BYTE *source, int width_in_pixels) {

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

    target[cols] = GREY(source[FI_RGBA_RED], source[FI_RGBA_GREEN], source[FI_RGBA_BLUE]);

    source += 3;

  }

}

void DLL_CALLCONV

FreeImage_ConvertLine32To8(BYTE *target, BYTE *source, int width_in_pixels) {

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

    target[cols] = GREY(source[FI_RGBA_RED], source[FI_RGBA_GREEN], source[FI_RGBA_BLUE]);

    source += 4;

  }

}

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

//   smart convert X to 8 bits

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

FIBITMAP * DLL_CALLCONV

FreeImage_ConvertTo8Bits(FIBITMAP *dib) {

  if (!FreeImage_HasPixels(dib)) {

    return NULL;

  }

  const FREE_IMAGE_TYPE image_type = FreeImage_GetImageType(dib);

  if (image_type != FIT_BITMAP && image_type != FIT_UINT16) {

    return NULL;

  }

  const unsigned bpp = FreeImage_GetBPP(dib);

  if (bpp != 8) {

    const unsigned width = FreeImage_GetWidth(dib);

    const unsigned height = FreeImage_GetHeight(dib);

    // Allocate a destination image

    FIBITMAP *new_dib = FreeImage_Allocate(width, height, 8);

    if (new_dib == NULL) {

      return NULL;

    }

    // Copy metadata from src to dst

    FreeImage_CloneMetadata(new_dib, dib);

    // Palette of destination image has already been initialized

    RGBQUAD *new_pal = FreeImage_GetPalette(new_dib);

    const FREE_IMAGE_COLOR_TYPE color_type = FreeImage_GetColorType(dib);

    if (image_type == FIT_BITMAP) {

      switch(bpp) {

        case 1:

        {

          if (color_type == FIC_PALETTE) {

            // Copy the palette

            RGBQUAD *old_pal = FreeImage_GetPalette(dib);

            new_pal[0] = old_pal[0];

            new_pal[255] = old_pal[1];

          } else if (color_type == FIC_MINISWHITE) {

            // Create a reverse grayscale palette

            CREATE_GREYSCALE_PALETTE_REVERSE(new_pal, 256);

          }

          // Expand and copy the bitmap data

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

            FreeImage_ConvertLine1To8(FreeImage_GetScanLine(new_dib, rows), FreeImage_GetScanLine(dib, rows), width);

          }

          return new_dib;

        }

        case 4 :

        {

          if (color_type == FIC_PALETTE) {

            // Copy the palette

            memcpy(new_pal, FreeImage_GetPalette(dib), 16 * sizeof(RGBQUAD));

          }

          // Expand and copy the bitmap data

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

            FreeImage_ConvertLine4To8(FreeImage_GetScanLine(new_dib, rows), FreeImage_GetScanLine(dib, rows), width);         

          }

          return new_dib;

        }

        case 16 :

        {

          // Expand and copy the bitmap data

          if (IS_FORMAT_RGB565(dib)) {

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

              FreeImage_ConvertLine16To8_565(FreeImage_GetScanLine(new_dib, rows), FreeImage_GetScanLine(dib, rows), width);

            }

          } else {

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

              FreeImage_ConvertLine16To8_555(FreeImage_GetScanLine(new_dib, rows), FreeImage_GetScanLine(dib, rows), width);

            }

          }

          return new_dib;

        }

        case 24 :

        {

          // Expand and copy the bitmap data

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

            FreeImage_ConvertLine24To8(FreeImage_GetScanLine(new_dib, rows), FreeImage_GetScanLine(dib, rows), width);          

          }

          return new_dib;

        }

        case 32 :

        {

          // Expand and copy the bitmap data

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

            FreeImage_ConvertLine32To8(FreeImage_GetScanLine(new_dib, rows), FreeImage_GetScanLine(dib, rows), width);

          }

          return new_dib;

        }

      }

    } else if (image_type == FIT_UINT16) {

      const unsigned src_pitch = FreeImage_GetPitch(dib);

      const unsigned dst_pitch = FreeImage_GetPitch(new_dib);

      const BYTE *src_bits = FreeImage_GetBits(dib);

      BYTE *dst_bits = FreeImage_GetBits(new_dib);

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

        const WORD *const src_pixel = (WORD*)src_bits;

        BYTE *dst_pixel = (BYTE*)dst_bits;

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

          dst_pixel[cols] = (BYTE)(src_pixel[cols] >> 8);

        }

        src_bits += src_pitch;

        dst_bits += dst_pitch;

      }

      return new_dib;

    } 

  } // bpp != 8

  return FreeImage_Clone(dib);

}

FIBITMAP * DLL_CALLCONV

FreeImage_ConvertToGreyscale(FIBITMAP *dib) {

  if (!FreeImage_HasPixels(dib)) {

    return NULL;

  }

  const FREE_IMAGE_COLOR_TYPE color_type = FreeImage_GetColorType(dib);

  if (color_type == FIC_PALETTE || color_type == FIC_MINISWHITE) {

    const unsigned bpp = FreeImage_GetBPP(dib);

    const unsigned width  = FreeImage_GetWidth(dib);

    const unsigned height = FreeImage_GetHeight(dib);

    FIBITMAP *new_dib = FreeImage_Allocate(width, height, 8);

    if (new_dib == NULL) {

      return NULL;

    }

    // Copy metadata from src to dst

    FreeImage_CloneMetadata(new_dib, dib);

    // Create a greyscale palette

    BYTE grey_pal[256];

    const RGBQUAD *pal = FreeImage_GetPalette(dib);

    const unsigned size = CalculateUsedPaletteEntries(bpp);

    for (unsigned i = 0; i < size; i++) {

      grey_pal[i] = GREY(pal->rgbRed, pal->rgbGreen, pal->rgbBlue);

      pal++;

    }

    const BYTE *src_bits = FreeImage_GetBits(dib);

    BYTE *dst_bits = FreeImage_GetBits(new_dib);

    const unsigned src_pitch = FreeImage_GetPitch(dib);

    const unsigned dst_pitch = FreeImage_GetPitch(new_dib);

    switch(bpp) {

      case 1:

      {

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

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

            const unsigned pixel = (src_bits[x >> 3] & (0x80 >> (x & 0x07))) != 0;

            dst_bits[x] = grey_pal[pixel];

          }

          src_bits += src_pitch;

          dst_bits += dst_pitch;

        }

      }

      break;

      case 4:

      {

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

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

            const unsigned pixel = x & 0x01 ? src_bits[x >> 1] & 0x0F : src_bits[x >> 1] >> 4;

            dst_bits[x] = grey_pal[pixel];

          }

          src_bits += src_pitch;

          dst_bits += dst_pitch;

        }

      }

      break;

      case 8:

      {

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

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

            dst_bits[x] = grey_pal[src_bits[x]];

          }

          src_bits += src_pitch;

          dst_bits += dst_pitch;

        }

      }

      break;

    }

    return new_dib;

  } 

  // Convert the bitmap to 8-bit greyscale

  return FreeImage_ConvertTo8Bits(dib);

}