Don't sync color and transparency of image layers by default

CHANGES.md

@@ -4,6 +4,8 @@ Full changelog
 v0.16.0 (unreleased)
 --------------------
 
+* Don't sync color and transparency of image layers by default. [#2116]
+
 * Python 2.7 and 3.5 are no longer supported. [#2075]
 
 * Fixed bugs in the profile viewer that occurred when using the profile viewer and

glue/viewers/image/qt/tests/test_data_viewer.py

@@ -44,6 +44,19 @@ def init_data(self):
     def test_double_add_ignored(self):
         pass
 
+    def test_update_data_processed_if_data_present(self):
+
+        # Patch for the main test of the same name - we need to explicilty set
+        # global_sync to True here for things to work correctly.
+
+        self.init_draw_count()
+        self.data_collection.append(self.data)
+        self.viewer.add_data(self.data)
+        ct0 = self.draw_count
+        self.viewer.state.layers[0].global_sync = True
+        self.data.style.color = 'blue'
+        assert self.draw_count > ct0
+
     def test_slice_change_single_draw(self):
 
         # Regression test for a bug that caused Matplotlib to draw once per

glue/viewers/image/state.py

@@ -493,9 +493,9 @@ class ImageLayerState(BaseImageLayerState):
     stretch = DDSCProperty(docstring='The stretch used to render the layer, '
                                      'which should be one of ``linear``, '
                                      '``sqrt``, ``log``, or ``arcsinh``')
-    global_sync = DDCProperty(True, docstring='Whether the color and transparency '
-                                              'should be synced with the global '
-                                              'color and transparency for the data')
+    global_sync = DDCProperty(False, docstring='Whether the color and transparency '
+                                               'should be synced with the global '
+                                               'color and transparency for the data')
 
     def __init__(self, layer=None, viewer_state=None, **kwargs):