color2.c

int api_openwin(char *buf, int xsiz, int ysiz, int col_inv, char *title);
void api_closewin(int win);
void api_refreshwin(int win, int x0, int y0, int x1, int y1);
void api_boxfilwin(int win, int x0, int y0, int x1, int y1, int col);
void api_linewin(int win, int x0, int y0, int x1, int y1, int col);
int api_getkey(int mode);

void api_initmalloc(void);
char *api_malloc(int size);
void api_free(char *addr, int size);

void api_end(void);

unsigned char rgb2pal(int r, int g, int b, int x, int y);

void HariMain(void)
{
  char *buf;
  int win, x, y, r, g, b;

  api_initmalloc();
  buf = api_malloc(144 * 164);
  win = api_openwin(buf, 144, 164, -1, "color2");
  for (y = 0; y < 128; y++) {
    for (x = 0; x < 128; x++) {
      buf[(x + 8) + (y + 28) * 144] = rgb2pal(x * 2, y * 2, 0, x, y);
    }
  }
  api_refreshwin(win, 8, 28, 136, 156);
  api_getkey(1);		/* キー入力でアプリ終了 */

  api_end();
}

unsigned char rgb2pal(int r, int g, int b, int x, int y)
{
  static int table[4] = {3, 1, 0, 2};
  int i;

  x &= 1;			/* 偶数か奇数か */
  y &= 1;
  i = table[x + y * 2];		/* 中間色を作るための定数 */
  r = (r * 21) / 256;		/* これで 0〜20になる */
  g = (g * 21) / 256;
  b = (b * 21) / 256;
  r = (r + i) / 4;		/* これで 0〜5になる */
  g = (g + i) / 4;
  b = (b + i) / 4;

  return 16 + r + g * 6 + b * 36;
}