gistfile1.c

uint8* dest = malloc(width * height * 4);
short* src = imgData;
for (int i = 0; i < width * height; ++i) {
  short x = *src++;
  *dest++ = (x >> 8) & 0xFF;
  *dest++ = x & 0xFF;
  *dest++ = 0;
  *dest++ = 0;
}

        uint8* dest = (uint8*) malloc(width * height * 4);
        short* subscript = (short*) imgData;
        for (int i = 0; i < width * height; ++i) {
            short x = *subscript++;
            *dest++ = (x >> 8) & 0xFF;
            *dest++ = x & 0xFF;
            *dest++ = 255;
            *dest++ = 255;
        }
        uint8 *fourchan = dest;

        uint8 *fourchan = (uint8*) malloc(sizeof(uint8) * width * height * 4);
        short cur;
        short *subscript = (short*) imgData;
        for (int i = 0; i < width * height; i++) {
            cur = subscript[i] + 1000;
            fourchan[i*4] = cur;
        }