From 381fe7527308e6a00442de5e26a13c4466911125 Mon Sep 17 00:00:00 2001
From: Kris Stern <krisastern@gmail.com>
Date: Thu, 7 May 2020 03:28:26 +0800
Subject: [PATCH] Debug to make the new preferred_cmap attribute of visual to
 work

Edit files to remove unused imports

Comment out problematic set_preferred_cmap line

Get rid of unneeded set_preferred_cmap lines

Update docstring of preferred_cmap callback property in visual

Clean up after conducting more thorough testing

Fix typo in doctring

Tidy up and debug

Remove preferred_cmap as a DeferredDrawCallbackProperty

Remove unused line

Add preferred_cmap attribute for SunPy SJI maps

Tidy up by removing print statement for testing

Make changes according to reviewer suggestion

Make changes according to reviewer's suggestions

Make changes according to reviewer's suggestions

Make modifications according to reviewer suggestions
---
 glue/core/registry.py       |  2 +-
 glue/core/state.py          |  2 ++
 glue/core/visual.py         | 24 +++++++++++++++++++++---
 glue/viewers/image/state.py |  8 ++++----
 4 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/glue/core/registry.py b/glue/core/registry.py
index 98b983925..b5e325077 100644
--- a/glue/core/registry.py
+++ b/glue/core/registry.py
@@ -37,7 +37,7 @@ def __init__(self):
         self._disable = False
 
     def register(self, obj, label, group=None):
-        """ Register label with object (possibly disamgiguating)
+        """ Register label with object (possibly disambiguating)
 
         :param obj: The object to label
         :param label: The desired label
diff --git a/glue/core/state.py b/glue/core/state.py
index f214b2303..413d00393 100644
--- a/glue/core/state.py
+++ b/glue/core/state.py
@@ -709,6 +709,8 @@ def _save_style(style, context):
 @loader(VisualAttributes)
 def _load_style(rec, context):
     result = VisualAttributes()
+    if 'preferred_cmap' in result._atts:
+        result._atts.remove('preferred_cmap')
     for attr in result._atts:
         setattr(result, attr, rec[attr])
     return result
diff --git a/glue/core/visual.py b/glue/core/visual.py
index bce2ef72b..07b73d1f3 100644
--- a/glue/core/visual.py
+++ b/glue/core/visual.py
@@ -1,6 +1,8 @@
 from matplotlib.colors import ColorConverter
+from matplotlib.cm import get_cmap
 
 from glue.config import settings
+
 from echo import callback_property, HasCallbackProperties
 
 # Define acceptable line styles
@@ -25,7 +27,7 @@ class VisualAttributes(HasCallbackProperties):
 
     """
 
-    def __init__(self, parent=None, washout=False, color=None, alpha=None):
+    def __init__(self, parent=None, washout=False, color=None, alpha=None, preferred_cmap=None):
 
         super(VisualAttributes, self).__init__()
 
@@ -36,9 +38,10 @@ def __init__(self, parent=None, washout=False, color=None, alpha=None):
 
         self.parent = parent
         self._atts = ['color', 'alpha', 'linewidth', 'linestyle', 'marker',
-                      'markersize']
+                      'markersize', 'preferred_cmap']
         self.color = color
         self.alpha = alpha
+        self.preferred_cmap = preferred_cmap
         self.linewidth = 1
         self.linestyle = 'solid'
         self.marker = 'o'
@@ -94,6 +97,20 @@ def color(self, value):
         else:
             self._color = value
 
+    @callback_property
+    def preferred_cmap(self):
+        """
+        A preferred colormap specified using Matplotlib notation
+        """
+        return self._preferred_cmap
+
+    @preferred_cmap.setter
+    def preferred_cmap(self, value):
+        if isinstance(value, str):
+            self._preferred_cmap = get_cmap(value)
+        else:
+            self._preferred_cmap = value
+
     @callback_property
     def alpha(self):
         """
@@ -163,7 +180,8 @@ def __setattr__(self, attribute, value):
 
         # Check that the attribute exists (don't allow new attributes)
         allowed = set(['color', 'linewidth', 'linestyle',
-                       'alpha', 'parent', 'marker', 'markersize'])
+                       'alpha', 'parent', 'marker', 'markersize',
+                       'preferred_cmap'])
         if attribute not in allowed and not attribute.startswith('_'):
             raise Exception("Attribute %s does not exist" % attribute)
 
diff --git a/glue/viewers/image/state.py b/glue/viewers/image/state.py
index 40215b9f5..762676aa0 100644
--- a/glue/viewers/image/state.py
+++ b/glue/viewers/image/state.py
@@ -87,9 +87,9 @@ class ImageViewerState(MatplotlibDataViewerState):
                                             'which the images are shown')
     slices = DDCProperty(docstring='The current slice along all dimensions')
     color_mode = DDSCProperty(0, docstring='Whether each layer can have '
-                                                    'its own colormap (``Colormaps``) or '
-                                                    'whether each layer is assigned '
-                                                    'a single color (``One color per layer``)')
+                                           'its own colormap (``Colormaps``) or '
+                                           'whether each layer is assigned '
+                                           'a single color (``One color per layer``)')
 
     dpi = DDCProperty(72, docstring='The resolution (in dots per inch) of density maps, if present')
 
@@ -544,7 +544,7 @@ def __init__(self, layer=None, viewer_state=None, **kwargs):
         self.update_from_dict(kwargs)
 
         if self.cmap is None:
-            self.cmap = colormaps.members[0][1]
+            self.cmap = self.layer.style.preferred_cmap or colormaps.members[0][1]
 
     def _update_attribute(self, *args):
         if self.layer is not None: