freeimage-show-in-terminal.c

// show an image in the terminal using ascii colors
// demonstrates raw pixel access
// (only works on certain image file types, though)
#include <stdio.h>
#include <FreeImage.h>

int meta(FIBITMAP *dib) {
  FITAG *tag = NULL;
  FIMETADATA *mdhandle = NULL;
  mdhandle = FreeImage_FindFirstMetadata(FIMD_EXIF_MAIN, dib, &tag);
  if(mdhandle) {
    do {
      // process the tag
      printf("%s\n", FreeImage_GetTagKey(tag));
      // ...
    } while(FreeImage_FindNextMetadata(mdhandle, &tag));

    FreeImage_FindCloseMetadata(mdhandle);
  } else {
    printf("no metadata found for %p \n", dib);
  }
}

int dump (FIBITMAP *dib) {
  unsigned width = FreeImage_GetWidth(dib);
  unsigned height = FreeImage_GetHeight(dib);
  unsigned pitch = FreeImage_GetPitch(dib);
  unsigned line = FreeImage_GetLine(dib);
  int x, y;
  FREE_IMAGE_TYPE image_type = FreeImage_GetImageType(dib);
  BYTE *bits = (BYTE*)FreeImage_GetBits(dib);
  // test pixel access avoiding scanline calculations
  // to speed-up the image processing
  int bytespp = FreeImage_GetLine(dib) / FreeImage_GetWidth(dib);

  if(image_type == FIT_BITMAP) {
    for(y = height-1; y >= 0; y--) {
      printf("\n");
      for(x = 0; x < width; x++) {
        int r,g,b;
        if((bytespp == 3) || (bytespp == 4)) {
          r = bits[y*pitch + x*bytespp + FI_RGBA_RED];
          g = bits[y*pitch + x*bytespp + FI_RGBA_GREEN];
          b = bits[y*pitch + x*bytespp + FI_RGBA_BLUE];
        } else if ((bytespp == 1)) {
          r = g = b = bits[y*pitch + x*bytespp];
        } else {
          printf("unknown bpp %d\n", bytespp);
          return -1;
        }
        // print a full-blown square with the right color (most
        // terminals should support this).
        printf("\x1b[38;2;%d;%d;%dm█", r,g,b);
      }
    }
  } else {
    printf("unknown image type\n");
  }
}

int main(int argc, char** argv) {
  if(argc != 2) {
    printf("missing filename argument\n");
    return -1;
  }
  char *filename = argv[1];
  FREE_IMAGE_FORMAT fif = FreeImage_GetFIFFromFilename(filename);
  FIBITMAP *dib = FreeImage_Load(fif, filename, 0);
  printf("loaded %p\n", dib);
  if(dib) {
    printf("%p is %d x %d x %d\n", dib, FreeImage_GetWidth(dib), FreeImage_GetHeight(dib), FreeImage_GetBPP(dib));
    meta(dib);
    dump(dib);
    FreeImage_Unload(dib);
  }
}