24位位图bmp转换为字符

 1  #include <cstdio>
 2  #include <cstring>
 3  #include <stdint.h>
 4  #include <windows.h>
 5  int32_t width,height;
 6  RGBQUAD *pixels;
 7  bool OpenBitmap(char const *filename)
 8  {
 9      FILE *file = fopen(filename, "rb");
10      if (file)
11      {
12          width=0;
13          height=0;
14          BITMAPFILEHEADER bf;
15          BITMAPINFOHEADER bi;
16          fread(&bf, sizeof(bf), 1, file);
17          fread(&bi, sizeof(bi), 1, file);
18          if(bi.biBitCount!=24)
19              return false;
20          if(bi.biCompression!=BI_RGB)
21              return false;
22          width=bi.biWidth;
23          height=bi.biHeight;
24          pixels=new RGBQUAD[width*height];
25          uint32_t rowSize = (bi.biBitCount * width + 31) / 32 * 4;
26          uint8_t *line = new uint8_t[rowSize];
27          for (int y = 0; y < height; y++)
28          {
29              fread(line, rowSize, 1, file);
30              for (int x = 0; x < width; x++)
31              {
32                  uint8_t *color = line + x * 3;
33                  RGBQUAD *pixel = &pixels[(height-y-1) * width+x];
34                  pixel->rgbBlue  = color[0];
35                  pixel->rgbGreen = color[1];
36                  pixel->rgbRed   = color[2];
37              }
38          }
39          delete[] line;
40          fclose(file);
41          return true;
42      }
43      return false;
44  }
45  RGBQUAD GetColor(int x, int y, int w, int h)
46  {
47      int r = 0, g = 0, b = 0;
48      for (int i = 0; i < w; i++)
49      {
50          if (i + x >= width) continue;
51          for (int j = 0; j < h; j++)
52          {
53              if (j + y >= height) continue;
54              RGBQUAD const& color = pixels[(y + j) * width + (x + i)];
55              r += color.rgbRed;
56              g += color.rgbGreen;
57              b += color.rgbBlue;
58          }
59      }
60      return RGBQUAD{r / (w * h), g / (w * h),b / (w * h)};
61  }
62  char ColorToCharacter(RGBQUAD const& color)
63  {
64      int brightness = (color.rgbRed + color.rgbGreen + color.rgbBlue) / 3;
65      static char const *characters = "Qo0V1;:*-. ";
66      int len = strlen(characters);
67      int span = 0xFF / len;
68      int cidx = brightness / span;
69      if (cidx == len)
70          cidx--;
71      return characters[cidx];
72  }
73  void OutputAscii(const char* filename, int w, int h)
74  {
75      FILE *file=fopen(filename,"a+");
76      int x = width  / w;
77      int y = height / h;
78      for (int i = 0; i < height; i += y)
79      {
80          for (int j = 0; j < width; j += x)
81          {
82              RGBQUAD color = GetColor(j, i, x, y);
83              fprintf(file, "%c", ColorToCharacter(color));
84              //printf("%c", ColorToCharacter(color));
85          }
86          fprintf(file, "
");
87          //printf("
");
88      }
89      delete [] pixels;
90      fclose(file);
91  }
92  int main()
93  {
94       if(OpenBitmap("a.bmp"))
95          OutputAscii("a.txt",width/6,height/12);
96      return 0;
97  }