Function writeSignature

depends/lodepng/lodepng.cpp:5090–5097

static unsigned writeSignature(ucvector* out) {
  size_t pos = out->size;
  const unsigned char signature[] = {137, 80, 78, 71, 13, 10, 26, 10};
  /*8 bytes PNG signature, aka the magic bytes*/
  if(!ucvector_resize(out, out->size + 8)) return 83; /*alloc fail*/
  lodepng_memcpy(out->data + pos, signature, 8);
  return 0;
}

static unsigned addChunk_IHDR(ucvector* out, unsigned w, unsigned h,
                              LodePNGColorType colortype, unsigned bitdepth, unsigned interlace_method) {