色差による画像処理

ＬＣＤや７ＳＥＧに表示される数字を自動で読み取りたいと思って実験してみた。画像処理はほとんどやったことがないのだがググってみると一般的には複数の画像処理を行い最終的には二値化画像を生成するようなのでまねてやってみたら．．．元画像の品質や外光による影響を大きく受けたりして調整作業がとてもシビアだ。

もっと安直な方法はないものかと．．．外光の映り込みによる影響を受けること、フルカラー画像をグレイスケール変換してしまうと重要な色情報が欠落してしまうこと、などから輝度差を除外した色差による画像処理方法を考えてみた。

色差は隣接するピクセルのＲＧＢ値をそれぞれ減算して求めるが輝度差の影響を排除するため減算結果の最小値／最大値の差を色差とする方法を実験してみた。ＲＧＢの場合、輝度が違う同色は各ＲＧＢ値が一律に変化することに着目した方法である。

【色差の計算方法】

(100, 100, 100) -> (120, 120, 120) = (+20, +20, +20) ... 色差( 0)
(100, 100, 100) -> (120, 110, 100) = (+20, +10,   0) ... 色差(20)
(100, 100, 100) -> (120,  90,  80) = (+20, -10, -20) ... 色差(40)
(100, 100, 100) -> ( 50,  50,  10) = (-50, -50, -90) ... 色差(40)

int diffColor(RGBTRIPLE p1, RGBTRIPLE p2)
{
  int b = (int)p1.rgbtBlue  - (int)p2.rgbtBlue;
  int g = (int)p1.rgbtGreen - (int)p2.rgbtGreen;
  int r = (int)p1.rgbtRed   - (int)p2.rgbtRed;
  int max = r > g ? (r > b ? r : b) : (g > b ? g : b);
  int min = r < g ? (r < b ? r : b) : (g < b ? g : b);
  return max - min;
}

(100, 100, 100) -> (120, 120, 120) = (+20, +20, +20) ... 色差( 0)

(100, 100, 100) -> (120, 110, 100) = (+20, +10, 0) ... 色差(20)

(100, 100, 100) -> (120, 90, 80) = (+20, -10, -20) ... 色差(40)

(100, 100, 100) -> ( 50, 50, 10) = (-50, -50, -90) ... 色差(40)

int diffColor(RGBTRIPLE p1, RGBTRIPLE p2)

{

int b = (int)p1.rgbtBlue - (int)p2.rgbtBlue;

int g = (int)p1.rgbtGreen - (int)p2.rgbtGreen;

int r = (int)p1.rgbtRed - (int)p2.rgbtRed;

int max = r > g ? (r > b ? r : b) : (g > b ? g : b);

int min = r < g ? (r < b ? r : b) : (g < b ? g : b);

return max - min;

}

※単純にするため本プログラムでは人間の目の色感度差等の補正はしていないがカメラ側が補正しているなら同じように補正すべきかも。

最初はカラーエッジ検出だけを考えていたが色差が判断できるのならその逆の同色も判断できるだろうと指定ピクセルと同色のピクセルを検出する実験をしてみたところ想定外にうまくいってしまった。しかも数字認識処理のために画像イメージ全体を前処理する必要もなく極めて高速に処理できるというメリットがある。

【参考情報】
色差式というものがあるが今回は使っていない。

新しい色差式（CIE DE2000）について。
17. 色差について

【元画像】
test.bmp (クリック後に元画像のＤＬが可能)

【カラーエッジ検出】
./icdd test.bmp -e 5

【同色検出】
./icdd test.bmp -f 1950 1140 50

【プログラム (Eclipse-MinGW) 】
目視確認用のモノクロ画像を生成するプログラム。

/*
 main.cpp - Image Color Difference Detector

 Copyright (c) 2023 Sasapea's Lab. All right reserved.

 This library is free software; you can redistribute it and/or
 modify it under the terms of the GNU Lesser General Public
 License as published by the Free Software Foundation; either
 version 2.1 of the License, or (at your option) any later version.

 This library is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 Lesser General Public License for more details.

 You should have received a copy of the GNU Lesser General
 Public License along with this library; if not, write to the
 Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 Boston, MA  02111-1307  USA
 */
#include <stdio.h>
#include "bitmap.h"

#define OFFSET 1

typedef struct __attribute__((packed))
{
  int x, y, threshold;
} fill_t;

typedef struct __attribute__((packed))
{
  int x, y, width, height, count;
} box_t;

bool detect(const char *image, const char *save, int edge, fill_t *fill, box_t *box)
{
  Bitmap source, output;
  int x, y, i;

  if (!source.read(image))
  {
    printf("file not found: \"%s\"\n", image);
    return false;
  }

  int32_t width  = source.width();
  int32_t height = source.height();

  if (source.bitCount() != 24)
  {
    printf("image(\"%s\"): { width=%d, height=%d, bitCount=%u }\n", image, width, height, source.bitCount());
    printf("This program is only 24 bit color mode\n");
    return false;
  }

  width  = abs(width);
  height = abs(height);

  output.create(width, height);

  Bitmap::RGBTRIPLE color = source.getPixelColor(fill->x, fill->y);

  for (y = 0; y < height; ++y)
  {
    for (x = OFFSET; x < width; ++x)
    {
      Bitmap::RGBTRIPLE c = source.getPixelColor(x, y);
      if ((edge && (Bitmap::diffColor(source.getPixelColor(x - OFFSET, y), c) >= edge))
        || (fill && (Bitmap::diffColor(color, c) < fill->threshold)))
        output.setPixel(x, y, true);
    }
  }

  for (x = 0; x < width; ++x)
  {
    for (y = OFFSET; y < height; ++y)
    {
      Bitmap::RGBTRIPLE c = source.getPixelColor(x, y);
      if ((edge && (Bitmap::diffColor(source.getPixelColor(x, y - OFFSET), c) >= edge))
        || (fill && (Bitmap::diffColor(color, c) < fill->threshold)))
        output.setPixel(x, y, true);
    }
  }

  for (i = 0; i < box->count; ++i)
  {
    int off = box->width * i + box->x;
    for (x = 0; x < box->width; ++x)
    {
      output.setPixel(off + x, box->y, true);
      output.setPixel(off + x, box->y + box->height, true);
    }
    for (y = 0; y < box->height; ++y)
    {
      output.setPixel(off, box->y + y, true);
      output.setPixel(off + box->width, box->y + y, true);
    }
  }

  return output.write(save);
}

void usage(void)
{
  printf("Image Color Difference Detector, version 1.00\n");
  printf("Copyright(c) 2023 Sasapea's Lab. All right reserved.\n");
  printf("\n");
  printf("Usage: icdd [options] image-file.bmp\n");
  printf("\n");
  printf("  options:\n");
  printf("    -o filename  ... save file name\n");
  printf("    -e n         ... edge threshold\n");
  printf("    -f x y n     ... paint fill\n");
  printf("    -b x y w h n ... draw box\n");
  printf("    -h           ... this help\n");
  printf("\n");
  exit(1);
}

int main(int argc, char **argv)
{
  const char *name = nullptr;
  const char *save = "save.bmp";
  int edge = 0;
  fill_t fill = {};
  box_t  box  = {};
  for (int i = 1; i < argc; )
  {
    char *p = argv[i++];
    if (*p == '-')
    {
      ++p;
      if (strcmp(p, "o") == 0)
      {
        if (i < argc)
          save = argv[i++];
      }
      else if (strcmp(p, "e") == 0)
      {
        if (i < argc)
          edge = atoi(argv[i++]);
      }
      else if (strcmp(p, "f") == 0)
      {
        if (i < argc)
          fill.x = atoi(argv[i++]);
        if (i < argc)
          fill.y = atoi(argv[i++]);
        if (i < argc)
          fill.threshold = atoi(argv[i++]);
      }
      else if (strcmp(p, "b") == 0)
      {
        if (i < argc)
          box.x = atoi(argv[i++]);
        if (i < argc)
          box.y = atoi(argv[i++]);
        if (i < argc)
          box.width = atoi(argv[i++]);
        if (i < argc)
          box.height = atoi(argv[i++]);
        if (i < argc)
          box.count = atoi(argv[i++]);
      }
      else if (strcmp(p, "h") == 0)
      {
        usage();
      }
    }
    else
    {
      name = p;
    }
  }

  if (!name)
    usage();

  return detect(name, save, edge, &fill, &box) ? 0 : 1;
}

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main.cpp - Image Color Difference Detector

This library is free software; you can redistribute it and/or

modify it under the terms of the GNU Lesser General Public

License as published by the Free Software Foundation; either

version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General

Public License along with this library; if not, write to the

Free Software Foundation, Inc., 59 Temple Place, Suite 330,

Boston, MA 02111-1307 USA

#include <stdio.h>

#include "bitmap.h"

#define OFFSET 1

typedef struct __attribute__((packed))

{

int x, y, threshold;

} fill_t;

typedef struct __attribute__((packed))

{

int x, y, width, height, count;

} box_t;

bool detect(const char *image, const char *save, int edge, fill_t *fill, box_t *box)

{

Bitmap source, output;

int x, y, i;

if (!source.read(image))

{

printf("file not found: \"%s\"\n", image);

return false;

}

int32_t width = source.width();

int32_t height = source.height();

if (source.bitCount() != 24)

{

printf("image(\"%s\"): { width=%d, height=%d, bitCount=%u }\n", image, width, height, source.bitCount());

printf("This program is only 24 bit color mode\n");

return false;

}

width = abs(width);

height = abs(height);

output.create(width, height);

Bitmap::RGBTRIPLE color = source.getPixelColor(fill->x, fill->y);

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

{

for (x = OFFSET; x < width; ++x)

{

Bitmap::RGBTRIPLE c = source.getPixelColor(x, y);

if ((edge && (Bitmap::diffColor(source.getPixelColor(x - OFFSET, y), c) >= edge))

|| (fill && (Bitmap::diffColor(color, c) < fill->threshold)))

output.setPixel(x, y, true);

}

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

{

for (y = OFFSET; y < height; ++y)

{

Bitmap::RGBTRIPLE c = source.getPixelColor(x, y);

if ((edge && (Bitmap::diffColor(source.getPixelColor(x, y - OFFSET), c) >= edge))

|| (fill && (Bitmap::diffColor(color, c) < fill->threshold)))

output.setPixel(x, y, true);

}

for (i = 0; i < box->count; ++i)

{

int off = box->width * i + box->x;

for (x = 0; x < box->width; ++x)

{

output.setPixel(off + x, box->y, true);

output.setPixel(off + x, box->y + box->height, true);

}

for (y = 0; y < box->height; ++y)

{

output.setPixel(off, box->y + y, true);

output.setPixel(off + box->width, box->y + y, true);

}

return output.write(save);

}

void usage(void)

{

printf("Image Color Difference Detector, version 1.00\n");

printf("\n");

printf("Usage: icdd [options] image-file.bmp\n");

printf("\n");

printf(" options:\n");

printf(" -o filename ... save file name\n");

printf(" -e n ... edge threshold\n");

printf(" -f x y n ... paint fill\n");

printf(" -b x y w h n ... draw box\n");

printf(" -h ... this help\n");

printf("\n");

exit(1);

}

int main(int argc, char **argv)

{

const char *name = nullptr;

const char *save = "save.bmp";

int edge = 0;

fill_t fill = {};

box_t box = {};

for (int i = 1; i < argc; )

{

char *p = argv[i++];

if (*p == '-')

{

++p;

if (strcmp(p, "o") == 0)

{

if (i < argc)

save = argv[i++];

}

else if (strcmp(p, "e") == 0)

{

if (i < argc)

edge = atoi(argv[i++]);

}

else if (strcmp(p, "f") == 0)

{

if (i < argc)

fill.x = atoi(argv[i++]);

if (i < argc)

fill.y = atoi(argv[i++]);

if (i < argc)

fill.threshold = atoi(argv[i++]);

}

else if (strcmp(p, "b") == 0)

{

if (i < argc)

box.x = atoi(argv[i++]);

if (i < argc)

box.y = atoi(argv[i++]);

if (i < argc)

box.width = atoi(argv[i++]);

if (i < argc)

box.height = atoi(argv[i++]);

if (i < argc)

box.count = atoi(argv[i++]);

}

else if (strcmp(p, "h") == 0)

{

usage();

}

else

{

name = p;

}

if (!name)

usage();

return detect(name, save, edge, &fill, &box) ? 0 : 1;

}

/*
 bitmap.h - Bitmap Library

 Copyright (c) 2023 Sasapea's Lab. All right reserved.

 This library is free software; you can redistribute it and/or
 modify it under the terms of the GNU Lesser General Public
 License as published by the Free Software Foundation; either
 version 2.1 of the License, or (at your option) any later version.

 This library is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 Lesser General Public License for more details.

 You should have received a copy of the GNU Lesser General
 Public License along with this library; if not, write to the
 Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 Boston, MA  02111-1307  USA
 */
#pragma once

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <sys/stat.h>

#define BITMAPFILETYPE "BM"

class Bitmap
{
  public:

    typedef struct __attribute__((packed))
    {
      uint8_t rgbtBlue;
      uint8_t rgbtGreen;
      uint8_t rgbtRed;
    } RGBTRIPLE;

    typedef struct __attribute__((packed))
    {
      uint8_t rgbBlue;
      uint8_t rgbGreen;
      uint8_t rgbRed;
      uint8_t rgbReserved;
    } RGBQUAD;

    const RGBTRIPLE COLOR_BLACK = { 0x00, 0x00, 0x00 };
    const RGBTRIPLE COLOR_WHITE = { 0xFF, 0xFF, 0xFF };

    Bitmap(void)
    : _bitmap(nullptr)
    {
      clear();
    }

    Bitmap(Bitmap& from) : Bitmap()
    {
      copy(from);
    }

    Bitmap(int32_t width, int32_t height, uint16_t bitCount) : Bitmap()
    {
      create(width, height, bitCount);
    }

    ~Bitmap(void)
    {
      clear();
    }

    void clear(void)
    {
      bitmap(nullptr);
    }

    bool copy(Bitmap& from)
    {
      BITMAPHEADER *bh = nullptr;

      if (from._bitmap)
      {
        if ((bh = (BITMAPHEADER *)malloc(from._bitmap->bfSize)))
        {
          memcpy(bh, from._bitmap, from._bitmap->bfSize);
          bitmap(bh);
        }
      }
      return bh != nullptr;
    }

    int32_t width(void)
    {
      return _width;
    }

    int32_t height(void)
    {
      return _height;
    }

    uint32_t bitCount(void)
    {
      return _bitCount;
    }

    size_t size(void)
    {
      return _sizeImage;
    }

    int32_t lineBytes(void)
    {
      return _lineBytes;
    }

    uint8_t *image(void)
    {
      return _images;
    }

    bool read(const char *file)
    {
      bool rv = false;
      BITMAPHEADER *bh;
      struct stat stb;
      FILE *fp;

      if ((fp = fopen(file, "rb")))
      {
        if (fstat(fileno(fp), &stb) != -1)
        {
          if ((size_t)stb.st_size >= sizeof(BITMAPHEADER))
          {
            if ((bh = (BITMAPHEADER *)malloc(stb.st_size)))
            {
              if (fread(bh, 1, stb.st_size, fp) != (size_t)stb.st_size)
              {
                free(bh);
                fprintf(stderr, "[Error] [%s] file read error\n", file);
              }
              else if (memcmp(&bh->bfType, BITMAPFILETYPE, sizeof(bh->bfType)) != 0)
              {
                free(bh);
                fprintf(stderr, "[Error] [%s] invalid BITMAPFILEHEADER.bfType\n", file);
              }
              else if (bh->bfOffBits < sizeof(BITMAPHEADER) + sizeof(RGBQUAD) * bh->biClrUsed)
              {
                free(bh);
                fprintf(stderr, "[Error] [%s] invalid BITMAPFILEHEADER.bfOffBits\n", file);
              }
              else if ((bh->biCompression == 0) && ((bh->bfOffBits + abs(lineBytes(bh) * bh->biHeight) > (size_t)stb.st_size)))
              {
                free(bh);
                fprintf(stderr, "[Error] [%s] invalid BITMAPFILEHEADER.bfOffBits\n", file);
              }
              else
              {
                bh->bfSize   = stb.st_size;
                bh->biPlanes = 1;
                if (bh->biCompression == 0)
                  bh->biSizeImage = abs(lineBytes(bh) * bh->biHeight);
                bitmap(bh);
                rv = true;
              }
            }
          }
        }
        fclose(fp);
      }
      return rv;
    }

    bool write(const char *file)
    {
      bool rv = false;
      FILE *fp;

      if (_bitmap)
      {
        if ((fp = fopen(file, "wb")))
        {
          rv = fwrite(_bitmap, 1, _bitmap->bfSize, fp) == _bitmap->bfSize;
          fclose(fp);
        }
      }
      return rv;
    }

    void create(int32_t width, int32_t height, uint16_t bitCount = 1)
    {
      BITMAPHEADER *bh;

      if (bitCount == 0)
        bitCount = 1;

      size_t hs = sizeof(BITMAPHEADER) + (bitCount > 8 ? 0 : sizeof(RGBQUAD) * (1 << bitCount));
      size_t is = abs(lineBytes(width, height, bitCount) * height);
      size_t fs = hs + is;

      if ((bh = (BITMAPHEADER *)calloc(fs, 1)))
      {
        memcpy(&bh->bfType, BITMAPFILETYPE, sizeof(bh->bfType));
        bh->bfSize      = fs;
        bh->bfOffBits   = hs;
        bh->biSize      = sizeof(BITMAPHEADER) - offsetof(BITMAPHEADER, biSize);
        bh->biWidth     = width;
        bh->biHeight    = height;
        bh->biPlanes    = 1;
        bh->biBitCount  = bitCount;
        bh->biSizeImage = is;
        bh->biClrUsed   = bitCount > 8 ? 0 : 1 << bitCount;
        bitmap(bh);
        if (bh->biClrUsed)
        {
          for (uint32_t i = 0; i < bh->biClrUsed - 1; ++i)
            setColorPallte(i, i, i, i);
          setColorPallte(bh->biClrUsed - 1, 0xFF, 0xFF, 0xFF);
        }
      }
    }

    void setColorPallte(uint8_t index, uint8_t blue, uint8_t green, uint8_t red)
    {
      RGBQUAD rgb = { .rgbBlue = blue, .rgbGreen = green, .rgbRed = red };
      setColorPallte(index, rgb);
    }

    void setColorPallte(uint8_t index, RGBTRIPLE rgbt)
    {
      RGBQUAD rgb = { .rgbBlue = rgbt.rgbtBlue, .rgbGreen = rgbt.rgbtGreen, .rgbRed = rgbt.rgbtRed };
      setColorPallte(index, rgb);
    }

    void setColorPallte(uint8_t index, RGBQUAD rgb)
    {
      if (_bitmap)
      {
        if (index < _bitmap->biClrUsed)
          _bitmap->biColors[index] = rgb;
      }
    }

    void setPixel(int x, int y, bool on)
    {
      if (confirm(x, y, 1))
      {
        uint8_t *img = &_images[(_lineBytes * y) + (x >> 3)];
        uint8_t  bit = 1 << (7 - (x & 7));
        if (on)
          *img |=  bit;
        else
          *img &= ~bit;
      }
    }

    bool getPixel(int x, int y)
    {
      return confirm(x, y, 1) && (_images[_lineBytes * y + (x >> 3)] & (1 << (7 - (x & 7))));
    }

    void setPixelColorIndex(int x, int y, uint8_t index)
    {
      if (confirm(x, y, 8) && (index < _bitmap->biClrUsed))
        _images[_lineBytes * y + x] = index;
    }

    uint8_t getPixelColorIndex(int x, int y)
    {
      return confirm(x, y, 8) ? _images[_lineBytes * y + x] : 0;
    }

    void setPixelColor(int x, int y, RGBTRIPLE color)
    {
      if (confirm(x, y, 24))
        *((RGBTRIPLE *)(_images + _lineBytes * y) + x) = color;
    }

    RGBTRIPLE getPixelColor(int x, int y)
    {
      return confirm(x, y, 24) ? *((RGBTRIPLE *)(_images + _lineBytes * y) + x) : COLOR_BLACK;
    }

    static
    int diffColor(RGBTRIPLE p1, RGBTRIPLE p2)
    {
      int b = (int)p1.rgbtBlue  - (int)p2.rgbtBlue;
      int g = (int)p1.rgbtGreen - (int)p2.rgbtGreen;
      int r = (int)p1.rgbtRed   - (int)p2.rgbtRed;
      int max = r > g ? (r > b ? r : b) : (g > b ? g : b);
      int min = r < g ? (r < b ? r : b) : (g < b ? g : b);
      return max - min;
    }

  protected:

    typedef struct __attribute__((packed))
    {
      //
      // BITMAPFILEHEADER
      //
      uint16_t bfType;
      uint32_t bfSize;
      uint16_t bfReserved1;
      uint16_t bfReserved2;
      uint32_t bfOffBits;
      //
      // BITMAPINFOHEADER
      //
      uint32_t biSize;
      int32_t  biWidth;
      int32_t  biHeight;
      uint16_t biPlanes;
      uint16_t biBitCount;
      uint32_t biCompression;
      uint32_t biSizeImage;
      int32_t  biXPelsPerMeter;
      int32_t  biYPelsPerMeter;
      uint32_t biClrUsed;
      uint32_t biClrImportant;
      RGBQUAD  biColors[0];
    } BITMAPHEADER;

    BITMAPHEADER *_bitmap;
    int32_t       _width;
    int32_t       _height;
    uint16_t      _bitCount;
    size_t        _sizeImage;
    int           _lineBytes;
    uint8_t      *_images;

    void bitmap(BITMAPHEADER *bh)
    {
      if (_bitmap)
        free(_bitmap);
      _bitmap = bh;
      if (bh)
      {
        _width     = bh->biWidth;
        _height    = bh->biHeight;
        _bitCount  = bh->biBitCount;
        _sizeImage = bh->biSizeImage;
        _lineBytes = lineBytes(bh);
        _images    = (uint8_t *)bh + bh->bfOffBits - (bh->biHeight > 0 ? (bh->biHeight - 1) * _lineBytes : 0);
      }
      else
      {
        _width     = 0;
        _height    = 0;
        _bitCount  = 0;
        _sizeImage = 0;
        _lineBytes = 0;
        _images    = nullptr;
      }
    }

    inline
    int32_t lineBytes(int32_t width, int32_t height, uint16_t bitCount)
    {
      int32_t bytes = ((abs(width) * (bitCount ? bitCount : 1) + 31) & ~31) >> 3;
      return height > 0 ? - bytes : bytes;
    }

    inline
    int32_t lineBytes(BITMAPHEADER *bh)
    {
      return lineBytes(bh->biWidth, bh->biHeight, bh->biBitCount);
    }

    bool confirm(int x, int y, uint16_t bitCount)
    {
      return (x >= 0) && (x < abs(_width)) && (y >= 0) && (y < abs(_height)) && (bitCount == _bitCount);
    }
};

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bitmap.h - Bitmap Library

This library is free software; you can redistribute it and/or

modify it under the terms of the GNU Lesser General Public

License as published by the Free Software Foundation; either

version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General

Public License along with this library; if not, write to the

Free Software Foundation, Inc., 59 Temple Place, Suite 330,

Boston, MA 02111-1307 USA

#pragma once

#include <stdio.h>

#include <stdlib.h>

#include <stdint.h>

#include <sys/stat.h>

#define BITMAPFILETYPE "BM"

class Bitmap

{

public:

typedef struct __attribute__((packed))

{

uint8_t rgbtBlue;

uint8_t rgbtGreen;

uint8_t rgbtRed;

} RGBTRIPLE;

typedef struct __attribute__((packed))

{

uint8_t rgbBlue;

uint8_t rgbGreen;

uint8_t rgbRed;

uint8_t rgbReserved;

} RGBQUAD;

const RGBTRIPLE COLOR_BLACK = { 0x00, 0x00, 0x00 };

const RGBTRIPLE COLOR_WHITE = { 0xFF, 0xFF, 0xFF };

Bitmap(void)

: _bitmap(nullptr)

{

clear();

}

Bitmap(Bitmap& from) : Bitmap()

{

copy(from);

}

Bitmap(int32_t width, int32_t height, uint16_t bitCount) : Bitmap()

{

create(width, height, bitCount);

}

~Bitmap(void)

{

clear();

}

void clear(void)

{

bitmap(nullptr);

}

bool copy(Bitmap& from)

{

BITMAPHEADER *bh = nullptr;

if (from._bitmap)

{

if ((bh = (BITMAPHEADER *)malloc(from._bitmap->bfSize)))

{

memcpy(bh, from._bitmap, from._bitmap->bfSize);

bitmap(bh);

}

return bh != nullptr;

}

int32_t width(void)

{

return _width;

}

int32_t height(void)

{

return _height;

}

uint32_t bitCount(void)

{

return _bitCount;

}

size_t size(void)

{

return _sizeImage;

}

int32_t lineBytes(void)

{

return _lineBytes;

}

uint8_t *image(void)

{

return _images;

}

bool read(const char *file)

{

bool rv = false;

BITMAPHEADER *bh;

struct stat stb;

FILE *fp;

if ((fp = fopen(file, "rb")))

{

if (fstat(fileno(fp), &stb) != -1)

{

if ((size_t)stb.st_size >= sizeof(BITMAPHEADER))

{

if ((bh = (BITMAPHEADER *)malloc(stb.st_size)))

{

if (fread(bh, 1, stb.st_size, fp) != (size_t)stb.st_size)

{

free(bh);

fprintf(stderr, "[Error] [%s] file read error\n", file);

}

else if (memcmp(&bh->bfType, BITMAPFILETYPE, sizeof(bh->bfType)) != 0)

{

free(bh);

fprintf(stderr, "[Error] [%s] invalid BITMAPFILEHEADER.bfType\n", file);

}

else if (bh->bfOffBits < sizeof(BITMAPHEADER) + sizeof(RGBQUAD) * bh->biClrUsed)

{

free(bh);

fprintf(stderr, "[Error] [%s] invalid BITMAPFILEHEADER.bfOffBits\n", file);

}

else if ((bh->biCompression == 0) && ((bh->bfOffBits + abs(lineBytes(bh) * bh->biHeight) > (size_t)stb.st_size)))

{

free(bh);

fprintf(stderr, "[Error] [%s] invalid BITMAPFILEHEADER.bfOffBits\n", file);

}

else

{

bh->bfSize = stb.st_size;

bh->biPlanes = 1;

if (bh->biCompression == 0)

bh->biSizeImage = abs(lineBytes(bh) * bh->biHeight);

bitmap(bh);

rv = true;

}

fclose(fp);

}

return rv;

}

bool write(const char *file)

{

bool rv = false;

FILE *fp;

if (_bitmap)

{

if ((fp = fopen(file, "wb")))

{

rv = fwrite(_bitmap, 1, _bitmap->bfSize, fp) == _bitmap->bfSize;

fclose(fp);

}

return rv;

}

void create(int32_t width, int32_t height, uint16_t bitCount = 1)

{

BITMAPHEADER *bh;

if (bitCount == 0)

bitCount = 1;

size_t hs = sizeof(BITMAPHEADER) + (bitCount > 8 ? 0 : sizeof(RGBQUAD) * (1 << bitCount));

size_t is = abs(lineBytes(width, height, bitCount) * height);

size_t fs = hs + is;

if ((bh = (BITMAPHEADER *)calloc(fs, 1)))

{

memcpy(&bh->bfType, BITMAPFILETYPE, sizeof(bh->bfType));

bh->bfSize = fs;

bh->bfOffBits = hs;

bh->biSize = sizeof(BITMAPHEADER) - offsetof(BITMAPHEADER, biSize);

bh->biWidth = width;

bh->biHeight = height;

bh->biPlanes = 1;

bh->biBitCount = bitCount;

bh->biSizeImage = is;

bh->biClrUsed = bitCount > 8 ? 0 : 1 << bitCount;

bitmap(bh);

if (bh->biClrUsed)

{

for (uint32_t i = 0; i < bh->biClrUsed - 1; ++i)

setColorPallte(i, i, i, i);

setColorPallte(bh->biClrUsed - 1, 0xFF, 0xFF, 0xFF);

}

void setColorPallte(uint8_t index, uint8_t blue, uint8_t green, uint8_t red)

{

RGBQUAD rgb = { .rgbBlue = blue, .rgbGreen = green, .rgbRed = red };

setColorPallte(index, rgb);

}

void setColorPallte(uint8_t index, RGBTRIPLE rgbt)

{

RGBQUAD rgb = { .rgbBlue = rgbt.rgbtBlue, .rgbGreen = rgbt.rgbtGreen, .rgbRed = rgbt.rgbtRed };

setColorPallte(index, rgb);

}

void setColorPallte(uint8_t index, RGBQUAD rgb)

{

if (_bitmap)

{

if (index < _bitmap->biClrUsed)

_bitmap->biColors[index] = rgb;

}

void setPixel(int x, int y, bool on)

{

if (confirm(x, y, 1))

{

uint8_t *img = &_images[(_lineBytes * y) + (x >> 3)];

uint8_t bit = 1 << (7 - (x & 7));

if (on)

*img |= bit;

else

*img &= ~bit;

}

bool getPixel(int x, int y)

{

return confirm(x, y, 1) && (_images[_lineBytes * y + (x >> 3)] & (1 << (7 - (x & 7))));

}

void setPixelColorIndex(int x, int y, uint8_t index)

{

if (confirm(x, y, 8) && (index < _bitmap->biClrUsed))

_images[_lineBytes * y + x] = index;

}

uint8_t getPixelColorIndex(int x, int y)

{

return confirm(x, y, 8) ? _images[_lineBytes * y + x] : 0;

}

void setPixelColor(int x, int y, RGBTRIPLE color)

{

if (confirm(x, y, 24))

*((RGBTRIPLE *)(_images + _lineBytes * y) + x) = color;

}

RGBTRIPLE getPixelColor(int x, int y)

{

return confirm(x, y, 24) ? *((RGBTRIPLE *)(_images + _lineBytes * y) + x) : COLOR_BLACK;

}

static

int diffColor(RGBTRIPLE p1, RGBTRIPLE p2)

{

int b = (int)p1.rgbtBlue - (int)p2.rgbtBlue;

int g = (int)p1.rgbtGreen - (int)p2.rgbtGreen;

int r = (int)p1.rgbtRed - (int)p2.rgbtRed;

int max = r > g ? (r > b ? r : b) : (g > b ? g : b);

int min = r < g ? (r < b ? r : b) : (g < b ? g : b);

return max - min;

}

protected:

typedef struct __attribute__((packed))

{

// BITMAPFILEHEADER

uint16_t bfType;

uint32_t bfSize;

uint16_t bfReserved1;

uint16_t bfReserved2;

uint32_t bfOffBits;

// BITMAPINFOHEADER

uint32_t biSize;

int32_t biWidth;

int32_t biHeight;

uint16_t biPlanes;

uint16_t biBitCount;

uint32_t biCompression;

uint32_t biSizeImage;

int32_t biXPelsPerMeter;

int32_t biYPelsPerMeter;

uint32_t biClrUsed;

uint32_t biClrImportant;

RGBQUAD biColors[0];

} BITMAPHEADER;

BITMAPHEADER *_bitmap;

int32_t _width;

int32_t _height;

uint16_t _bitCount;

size_t _sizeImage;

int _lineBytes;

uint8_t *_images;

void bitmap(BITMAPHEADER *bh)

{

if (_bitmap)

free(_bitmap);

_bitmap = bh;

if (bh)

{

_width = bh->biWidth;

_height = bh->biHeight;

_bitCount = bh->biBitCount;

_sizeImage = bh->biSizeImage;

_lineBytes = lineBytes(bh);

_images = (uint8_t *)bh + bh->bfOffBits - (bh->biHeight > 0 ? (bh->biHeight - 1) * _lineBytes : 0);

}

else

{

_width = 0;

_height = 0;

_bitCount = 0;

_sizeImage = 0;

_lineBytes = 0;

_images = nullptr;

}

inline

int32_t lineBytes(int32_t width, int32_t height, uint16_t bitCount)

{

int32_t bytes = ((abs(width) * (bitCount ? bitCount : 1) + 31) & ~31) >> 3;

return height > 0 ? - bytes : bytes;

}

inline

int32_t lineBytes(BITMAPHEADER *bh)

{

return lineBytes(bh->biWidth, bh->biHeight, bh->biBitCount);

}

bool confirm(int x, int y, uint16_t bitCount)

{

return (x >= 0) && (x < abs(_width)) && (y >= 0) && (y < abs(_height)) && (bitCount == _bitCount);

}

};

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