An image encoder for Gamebuino Classic bitmaps

bmpenc.cpp

#include <stdio.h>
#include <stdint.h>

/*---------------------------------------------------------------------------*/
/* stb_image config and inclusion */

#define STBI_ASSERT( x )

#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"
/*---------------------------------------------------------------------------*/

int main(int argc, const char* argv[]) {
  if (argc != 3) {
    fprintf(stderr, "USAGE: bmpenc inputfile arrayname\n");
    return 1;
  }

  int width, height;
  uint32_t* image = (uint32_t*)stbi_load(argv[1], &width, &height, NULL, STBI_rgb_alpha);

  printf("static const byte %sBlack[] PROGMEM = {\n", argv[2]);
  printf("  /* width  */ %d,\n", (width + 7) & ~7);
  printf("  /* height */ %d,\n", height);

  for (int y = 0; y < height; y++) {
    printf("  /* row %2d */", y);
    uint32_t* row = image + y * width;

    for (int x = 0; x < width; x += 8) {
      int byte = 0;

      for (int i = 0; i < 8; i++) {
        uint32_t color = (x + i) < width ? row[x + i] : 0;
        uint8_t  a = color >> 24;
        uint8_t  b = (color >> 16) & 255;
        uint8_t  g = (color >> 8) & 255;
        uint8_t  r = color & 255;

        if (a == 255) {
          byte |= 128 >> i;
        }
      }

      printf(" 0x%02x,", byte);
    }

    printf("\n");
  }

  printf("};\n\n");

  printf("static const byte %sWhite[] PROGMEM = {\n", argv[2]);
  printf("  /* width  */ %d,\n", (width + 7) & ~7);
  printf("  /* height */ %d,\n", height);

  for (int y = 0; y < height; y++) {
    printf("  /* row %2d */", y);
    uint32_t* row = image + y * width;

    for (int x = 0; x < width; x += 8) {
      int byte = 0;

      for (int i = 0; i < 8; i++) {
        uint32_t color = (x + i) < width ? row[x + i] : 0;
        uint8_t  a = color >> 24;
        uint8_t  b = (color >> 16) & 255;
        uint8_t  g = (color >> 8) & 255;
        uint8_t  r = color & 255;

        if (a == 255 && r == 255 && g == 255 && b == 255) {
          byte |= 128 >> i;
        }
      }

      printf(" 0x%02x,", byte);
    }

    printf("\n");
  }

  printf("};\n\n");

  printf("#if 0\n");
  printf("  gb.display.setColor(BLACK);\n");
  printf("  gb.display.drawBitmap(x, y, %sBlack);\n", argv[2]);
  printf("  gb.display.setColor(WHITE);\n");
  printf("  gb.display.drawBitmap(x, y, %sWhite);\n", argv[2]);
  printf("#endif\n");

  free((void*)image);
  return 0;
}