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- """A qt exporter."""
- import os
- import sys
- import tempfile
- import time
- from traitlets import default
- from .html import HTMLExporter
- class QtExporter(HTMLExporter):
- """A qt exporter."""
- paginate = None
- format = ""
- @default("file_extension")
- def _file_extension_default(self):
- return ".html"
- def _check_launch_reqs(self):
- if sys.platform.startswith("win") and self.format == "png":
- msg = "Exporting to PNG using Qt is currently not supported on Windows."
- raise RuntimeError(msg)
- from .qt_screenshot import QT_INSTALLED # noqa: PLC0415
- if not QT_INSTALLED:
- msg = (
- f"PyQtWebEngine is not installed to support Qt {self.format.upper()} conversion. "
- f"Please install `nbconvert[qt{self.format}]` to enable."
- )
- raise RuntimeError(msg)
- from .qt_screenshot import QtScreenshot # noqa: PLC0415
- return QtScreenshot
- def _run_pyqtwebengine(self, html):
- ext = ".html"
- temp_file = tempfile.NamedTemporaryFile( # noqa: SIM115
- suffix=ext, delete=False
- )
- filename = f"{temp_file.name[: -len(ext)]}.{self.format}"
- with temp_file:
- temp_file.write(html.encode("utf-8"))
- try:
- QtScreenshot = self._check_launch_reqs()
- s = QtScreenshot()
- s.capture(f"file://{temp_file.name}", filename, self.paginate)
- finally:
- # Ensure the file is deleted even if pyqtwebengine raises an exception
- os.unlink(temp_file.name)
- # Prefer Qt's in-memory bytes, but fall back to reading the file on disk
- data = getattr(s, "data", b"")
- if (not data) and os.path.exists(filename):
- deadline = time.time() + 5.0
- while time.time() < deadline:
- try:
- if os.path.getsize(filename) > 0:
- break
- except OSError:
- pass
- time.sleep(0.05)
- if os.path.exists(filename) and os.path.getsize(filename) > 0:
- with open(filename, "rb") as f:
- data = f.read()
- # Best-effort cleanup of the generated output file
- try:
- if os.path.exists(filename):
- os.unlink(filename)
- except OSError:
- pass
- return data
- def from_notebook_node(self, nb, resources=None, **kw):
- """Convert from notebook node."""
- self._check_launch_reqs()
- html, resources = super().from_notebook_node(nb, resources=resources, **kw)
- self.log.info("Building %s", self.format.upper())
- data = self._run_pyqtwebengine(html)
- self.log.info("%s successfully created", self.format.upper())
- # convert output extension
- # the writer above required it to be html
- resources["output_extension"] = f".{self.format}"
- return data, resources
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