void save_to_png(const char * filename)
{
std::FILE * file = fopen(filename, "w+");
dump_png24(file, this->gd.drawable.data, this->gd.drawable.width,
this->gd.drawable.height, this->gd.drawable.rowsize);
fclose(file);
}
void save_to_png(const char * filename)
{
std::FILE * file = fopen(filename, "w+");
dump_png24(file, this->gd.data(), this->gd.width(),
this->gd.height(), this->gd.rowsize(), true);
fclose(file);
}