Allow specifying visual attributes when creating subset group

CHANGES.md

@@ -4,6 +4,8 @@ Full changelog
 v1.4.0 (unreleased)
 -------------------
 
+* Add support for specifying visual attributes when creating a subset group. [#2297]
+
 * Modify profile viewer so that when in 'Sum' mode, parts of profiles
   with no valid values are NaN rather than zero.
 

glue/core/data_collection.py

@@ -249,7 +249,7 @@ def register_to_hub(self, hub):
                       lambda msg: self._sync_link_manager(),
                       filter=lambda x: x.sender in self._data)
 
-    def new_subset_group(self, label=None, subset_state=None):
+    def new_subset_group(self, label=None, subset_state=None, **kwargs):
         """
         Create and return a new Subset Group.
 
@@ -265,11 +265,11 @@ def new_subset_group(self, label=None, subset_state=None):
         :class:`~glue.core.subset_group.SubsetGroup`
         """
         from glue.core.subset_group import SubsetGroup
-        color = settings.SUBSET_COLORS[self._sg_count % len(settings.SUBSET_COLORS)]
+        kwargs.setdefault("color", settings.SUBSET_COLORS[self._sg_count % len(settings.SUBSET_COLORS)])
         self._sg_count += 1
         label = label or 'Subset %i' % self._sg_count
 
-        result = SubsetGroup(color=color, label=label, subset_state=subset_state)
+        result = SubsetGroup(label=label, subset_state=subset_state, **kwargs)
         self._subset_groups.append(result)
         result.register(self)
         return result

glue/core/subset_group.py

@@ -89,7 +89,7 @@ def __setgluestate__(cls, rec, context):
 
 class SubsetGroup(HubListener):
 
-    def __init__(self, color=settings.SUBSET_COLORS[0], alpha=0.5, label=None, subset_state=None):
+    def __init__(self, label=None, subset_state=None, **kwargs):
         """
         Create a new empty SubsetGroup
 
@@ -105,11 +105,13 @@ def __init__(self, color=settings.SUBSET_COLORS[0], alpha=0.5, label=None, subse
 
         self.label = label
 
-        self.style = VisualAttributes(parent=self)
-        self.style.markersize *= 2.5
-        self.style.linewidth *= 2.5
-        self.style.color = color
-        self.style.alpha = alpha
+        visual_args = {k: v for k, v in kwargs.items() if k in VisualAttributes.DEFAULT_ATTS}
+        visual_args.setdefault("color", settings.SUBSET_COLORS[0])
+        visual_args.setdefault("alpha", 0.5)
+        visual_args.setdefault("linewidth", 2.5)
+        visual_args.setdefault("markersize", 7)
+
+        self.style = VisualAttributes(parent=self, **visual_args)
 
     @contract(data='isinstance(DataCollection)')
     def register(self, data):

glue/core/tests/test_subset_group.py

@@ -174,6 +174,40 @@ def test_deleted_subsets_dont_respawn(self):
         self.dc.append(d)
         assert len(d.subsets) == 0
 
+    def test_visual_attributes_default(self):
+        num_sg = len(self.dc.subset_groups)
+        sg = self.dc.new_subset_group()
+        expected_color = settings.SUBSET_COLORS[num_sg % len(settings.SUBSET_COLORS)]
+
+        # VisualAttributes stores color with lowercase letters
+        # but the values in settings.SUBSET_COLORS use uppercase
+        expected_color = expected_color.lower()
+        assert sg.style.color == expected_color
+        assert sg.style.alpha == 0.5
+        assert sg.style.linewidth == 2.5
+        assert sg.style.markersize == 7
+        assert sg.style.linestyle == 'solid'
+        assert sg.style.marker == 'o'
+        assert sg.style.preferred_cmap is None
+
+    def test_visual_attributes(self):
+        visual_attributes = dict(
+            color="#ff7f00",
+            alpha=0.3,
+            linewidth=4,
+            markersize=10,
+            marker='x',
+            linestyle='dashed',
+            preferred_cmap='viridis'
+        )
+        sg = self.dc.new_subset_group(**visual_attributes)
+        for attr, value in visual_attributes.items():
+            if attr == 'preferred_cmap':
+                from matplotlib.cm import get_cmap
+                assert sg.style.preferred_cmap == get_cmap(visual_attributes[attr])
+            else:
+                assert getattr(sg.style, attr, None) == value
+
 
 class TestSerialze(TestSubsetGroup):
 

glue/core/visual.py

@@ -37,6 +37,9 @@ class VisualAttributes(HasCallbackProperties):
         The size of the marker. Default is 3.
     """
 
+    DEFAULT_ATTS = ['color', 'alpha', 'linewidth', 'linestyle', 'marker',
+                    'markersize', 'preferred_cmap']
+
     def __init__(self, parent=None, color=None, alpha=None, preferred_cmap=None, linewidth=1, linestyle='solid', marker='o', markersize=3):
 
         super(VisualAttributes, self).__init__()
@@ -47,8 +50,7 @@ def __init__(self, parent=None, color=None, alpha=None, preferred_cmap=None, lin
         alpha = alpha or settings.DATA_ALPHA
 
         self.parent = parent
-        self._atts = ['color', 'alpha', 'linewidth', 'linestyle', 'marker',
-                      'markersize', 'preferred_cmap']
+        self._atts = self.DEFAULT_ATTS.copy()
         self.color = color
         self.alpha = alpha
         self.preferred_cmap = preferred_cmap