René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Tainted canvases may not be exported","articleBody":"I'm embedding some plotly graphs into a pyqt application using the QWebEngineView.  Everything seems to work well except for when I click on the \"Download plot as a png\" button in the toolbar.  I get the error:\r\n\r\n\u003e js: Uncaught SecurityError: Failed to execute 'toDataURL' on 'HTMLCanvasElement': Tainted canvases may not be exported.\r\n\r\nNot sure if this is a bug (it seems like it should work), or a feature request (I'd like to be able to do this).  Maybe there's a way around the error?\r\n\r\n```\r\nimport plotly.offline as po\r\nimport plotly.graph_objs as go\r\nimport plotly.express as px\r\n\r\nfrom PyQt5.QtWebEngineWidgets import QWebEngineView\r\nfrom PyQt5 import QtCore, QtWidgets\r\nimport sys\r\n\r\ndef show_qt(fig):\r\n    raw_html = '\u003chtml\u003e\u003chead\u003e\u003cmeta charset=\"utf-8\" /\u003e'\r\n    raw_html += '\u003cscript src=\"https://cdn.plot.ly/plotly-latest.min.js\"\u003e\u003c/script\u003e\u003c/head\u003e'\r\n    raw_html += '\u003cbody\u003e'\r\n    raw_html += po.plot(fig, include_plotlyjs=False, output_type='div')\r\n    raw_html += '\u003c/body\u003e\u003c/html\u003e'\r\n\r\n    fig_view = QWebEngineView()\r\n    # setHtml has a 2MB size limit, need to switch to setUrl on tmp file\r\n    # for large figures.\r\n    fig_view.setHtml(raw_html)\r\n    fig_view.show()\r\n    fig_view.raise_()\r\n    return fig_view\r\n\r\n\r\nif __name__ == '__main__':\r\n    app = QtWidgets.QApplication(sys.argv)\r\n\r\n    df = px.data.election()\r\n    geojson = px.data.election_geojson()\r\n\r\n    fig = px.choropleth(df, geojson=geojson, color=\"Bergeron\",\r\n                        locations=\"district\", featureidkey=\"properties.district\",\r\n                        projection=\"mercator\"\r\n                        )\r\n    fig.update_geos(fitbounds=\"locations\", visible=False)\r\n    fig.update_layout(margin={\"r\":0,\"t\":0,\"l\":0,\"b\":0})\r\n    fig_view = show_qt(fig)\r\n    sys.exit(app.exec_())\r\n```\r\n","author":{"url":"https://github.com/jwebster-LANL","@type":"Person","name":"jwebster-LANL"},"datePublished":"2020-09-22T18:43:46.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":1},"url":"https://github.com/2785/plotly.py/issues/2785"}