Deepcopy settings when creating factories (#356)

* Deepcopy settings when creating factories

Otherwise things get murky when we re-use the same settings
objects with multiple factories, as the factory plot
generation logic modifies settings (eg by recording
the list of found feature ids)

Fixes incomplete plots when used with atlas

* Simpler fix

DataPlotly/core/plot_factory.py

@@ -7,11 +7,13 @@
 (at your option) any later version.
 """
 
+
 import tempfile
 import os
 import re
 import plotly
 import plotly.graph_objs as go
+from copy import deepcopy
 from plotly import subplots
 
 from qgis.core import (
@@ -95,9 +97,9 @@ def __init__(self, settings: PlotSettings = None, context_generator: QgsExpressi
                  visible_region: QgsReferencedRectangle = None, polygon_filter: FilterRegion = None):
         super().__init__()
         if settings is None:
-            settings = PlotSettings('scatter')
-
-        self.settings = settings
+            self.settings = PlotSettings('scatter')
+        else:
+            self.settings = deepcopy(settings)
         self.context_generator = context_generator
         self.raw_plot = None
         self.plot_path = None

DataPlotly/core/plot_settings.py

@@ -6,10 +6,15 @@
 (at your option) any later version.
 """
 
+from copy import deepcopy
 from qgis.PyQt.QtCore import QFile, QIODevice
 from qgis.PyQt.QtXml import QDomDocument, QDomElement
 from qgis.core import QgsXmlUtils, QgsPropertyCollection, QgsPropertyDefinition
 
+def _pc_deepcopy(self, memo):
+    return QgsPropertyCollection(self)
+
+QgsPropertyCollection.__deepcopy__ = _pc_deepcopy
 
 class PlotSettings:  # pylint: disable=too-many-instance-attributes
     """