Method is_open

src/fl/codec/file_system_codecs.cpp.hpp:46–46

        : mDecoder(decoder), mCurrentFrame(nullptr), mFrameSize(pixelsPerFrame * 3),
          mCurrentPos(0), mPath(path), mHasValidFrame(false) { decodeNextFrameIfNeeded(); }
    bool is_open() const override { return mDecoder != nullptr; }
    void close() override { if (mDecoder) mDecoder->end(); }
    fl::size_t read(char* dst, fl::size_t bytesToRead) override {
        if (!mDecoder || !mHasValidFrame) return 0;