Fix issues with getting/calling stretches.

glue_plotly/common/image.py

@@ -139,9 +139,9 @@ def image_size_info(layer_state):
 
 def get_stretch(stretch_name):
     try:
-        return stretches(stretch_name)
+        return stretches.members[stretch_name]
     except TypeError:
-        return stretches[stretch_name]
+        return stretches[stretch_name]()
 
 
 def colorscale_info(layer_state, interval, contrast_bias):
@@ -151,7 +151,7 @@ def colorscale_info(layer_state, interval, contrast_bias):
     else:
         cmap = layer_state.cmap
         bounds = [layer_state.v_min, layer_state.v_max]
-    mapped_bounds = get_stretch(layer_state.stretch)()(contrast_bias(interval(bounds)))
+    mapped_bounds = get_stretch(layer_state.stretch)(contrast_bias(interval(bounds)))
     unmapped_space = np.linspace(0, 1, 60)
     mapped_space = np.linspace(mapped_bounds[0], mapped_bounds[1], 60)
     color_space = [cmap(b)[:3] for b in mapped_space]
@@ -329,7 +329,7 @@ def traces_for_image_layer(layer):
     if np.isscalar(array):
         array = np.atleast_2d(array)
 
-    img = get_stretch(layer_state.stretch)()(constrast_bias(interval(array)))
+    img = get_stretch(layer_state.stretch)(constrast_bias(interval(array)))
     img[np.isnan(img)] = 0
 
     z_bounds, colorscale = colorscale_info(layer_state, interval, constrast_bias)