Method showPixels

src/fl/channels/channel.cpp.hpp:449–673

}

void Channel::showPixels(PixelController<RGB, 1, 0xFFFFFFFF> &pixels) {
    FL_SCOPED_TRACE;

    // Safety check: don't modify buffer if driver is currently transmitting it
    if (mChannelData->isInUse()) {
        FL_WARN("Channel '" << mName << "': showPixels() called while mChannelData is in use by driver, attempting to wait");
        auto driver = mDriver.lock();
        if (!driver) {
            FL_ERROR("Channel '" << mName << "': No driver bound yet the mChannelData is in use - cannot transmit");
            return;
        }
        // wait until the driver is in a READY state.
        bool ok = driver->waitForReady();
        if (!ok) {
            FL_ERROR("Channel '" << mName << "': Timeout occurred while waiting for driver to become READY");
            return;
        }
        FL_WARN("Channel '" << mName << "': Engine became READY after waiting");
    }

    // Phase 5b of #2428: if the driver was pre-bound via setDriver() (legacy
    // addLeds<>-style controllers naming BusTraits<Bus::X>::instancePtr() in
    // their constructor), bypass ChannelManager entirely. Channels created via
    // the manager-based API (Channel::create(cfg) without affinity) keep their
    // existing per-frame re-selection so users can swap drivers at runtime.
    //
    // **Fast path (#2773 item 2.1):** the legacy `addLeds<NEOPIXEL>` flow is
    // by far the hot per-frame path on stock Blink. It needs no busKey
    // construction, no dynamic driver lookup, no busKey-miss diagnostics,
    // and no fallback `FL_ERROR` reporting — the driver was already pre-bound
    // in the controller's constructor. Pulling all of that boilerplate out
    // of `showPixels` lets the compiler keep the hot path compact and lets
    // the slow path's `fl::string` ops / `ChannelManager::selectDriverForChannel`
    // / diagnostic literals tree-shake on the slow-path branch's coldness.
    fl::shared_ptr<IChannelDriver> driver;
    if (mDriverPreBound) {
        driver = mDriver.lock();
        if (!driver) {
            // Pre-bound driver got destroyed (singleton shutdown, etc.). Silent
            // bail — this is unrecoverable from showPixels.
            return;
        }
    } else {
#if !defined(FASTLED_DISABLE_DYNAMIC_DRIVER) || !FASTLED_DISABLE_DYNAMIC_DRIVER
        driver = resolveDynamicDriver();
        if (!driver) {
            return;
        }
#else
        // Dynamic-driver lookup gated out via FASTLED_DISABLE_DYNAMIC_DRIVER
        // (#2926). The else branch is dead at runtime for every legacy
        // `addLeds<>` flavor — those pre-bind their driver in the ctor. The
        // gate lets `--gc-sections` drop the resolveDynamicDriver body plus
        // the ChannelManager::findDriverByName / selectDriverForChannel
        // chain (~400-900 B). Channels created via `Channel::create(cfg)`
        // without a pre-bound driver silently emit nothing under this flag —
        // user accepts the constraint.
        return;