Function _qt_app

SLiCAP/schematic/cli.py:25–35

Return (or create) a headless QApplication. Only sets QT_QPA_PLATFORM=offscreen when there is no existing app — never when called from inside a running GUI, because that would corrupt the parent's environment and cause all subsequent subprocesses to be invisible.

()

# ── Qt bootstrap ─────────────────────────────────────────────────────────────

def _qt_app():
    """Return (or create) a headless QApplication.

    Only sets QT_QPA_PLATFORM=offscreen when there is no existing app — never
    when called from inside a running GUI, because that would corrupt the
    parent's environment and cause all subsequent subprocesses to be invisible.
    """
    from PySide6.QtWidgets import QApplication
    if QApplication.instance() is None:
        os.environ.setdefault("QT_QPA_PLATFORM", "offscreen")
    return QApplication.instance() or QApplication(sys.argv[:1])


# ── shared scene loader ───────────────────────────────────────────────────────