Merge pull request #2467 from astrofrog/fix-default-stretch-density

Fix default stretch density

glue/tests/visual/py311-test-visual.json

@@ -1,7 +1,8 @@
 {
-    "glue.viewers.histogram.tests.test_viewer.test_simple_viewer": "cb08123fbad135ab614bb7ec13475fcc83321057d884fe80c3a32970b2d14762",
-    "glue.viewers.image.tests.test_viewer.test_simple_viewer": "72abd60b484d14f721254f027bb0ab9b36245d5db77eb87693f4dd9998fd28be",
-    "glue.viewers.profile.tests.test_viewer.test_simple_viewer": "f68a21be5080fec513388b2d2b220512e7b0df5498e2489da54e58708de435b3",
-    "glue.viewers.scatter.tests.test_viewer.test_simple_viewer": "1020a7bd3abe40510b9e03047c3b423b75c3c64ac18e6dcd6257173cec1ed53f",
-    "glue.viewers.image.tests.test_viewer.test_region_layer": "b54088d1f31562d309d35c5e90c0a382c7ba4c16cc0db8134e9532f71f047076"
-  }
+  "glue.viewers.histogram.tests.test_viewer.test_simple_viewer": "cb08123fbad135ab614bb7ec13475fcc83321057d884fe80c3a32970b2d14762",
+  "glue.viewers.image.tests.test_viewer.test_simple_viewer": "72abd60b484d14f721254f027bb0ab9b36245d5db77eb87693f4dd9998fd28be",
+  "glue.viewers.image.tests.test_viewer.test_region_layer": "b54088d1f31562d309d35c5e90c0a382c7ba4c16cc0db8134e9532f71f047076",
+  "glue.viewers.profile.tests.test_viewer.test_simple_viewer": "f68a21be5080fec513388b2d2b220512e7b0df5498e2489da54e58708de435b3",
+  "glue.viewers.scatter.tests.test_viewer.test_simple_viewer": "1020a7bd3abe40510b9e03047c3b423b75c3c64ac18e6dcd6257173cec1ed53f",
+  "glue.viewers.scatter.tests.test_viewer.test_scatter_density_map": "3379d655262769a6ccbdbaf1970bffa9237adbec23a93d3ab75da51b9a3e7f8b"
+}

glue/viewers/scatter/state.py

@@ -329,6 +329,7 @@ def __init__(self, viewer_state=None, layer=None, **kwargs):
         ScatterLayerState.vector_origin.set_display_func(self, vector_origin_display.get)
 
         self.setup_stretch_callback()
+        self.stretch = 'log'
 
         if self.viewer_state is not None:
             self.viewer_state.add_callback('x_att', self._on_xy_change, priority=10000)

glue/viewers/scatter/tests/test_viewer.py

@@ -1,11 +1,14 @@
 import numpy as np
 from numpy.testing import assert_allclose
 
+import matplotlib.pyplot as plt
+
 from glue.tests.visual.helpers import visual_test
 
 from glue.viewers.scatter.viewer import SimpleScatterViewer
 from glue.core.application_base import Application
 from glue.core.data import Data
+from glue.core.link_helpers import LinkSame
 
 
 @visual_test
@@ -29,6 +32,47 @@ def test_simple_viewer():
     return viewer.figure
 
 
+@visual_test
+def test_scatter_density_map():
+
+    # Test the scatter density map
+
+    np.random.seed(12345)
+
+    app = Application()
+
+    x = np.random.normal(3, 1, 100)
+    y = np.random.normal(2, 1.5, 100)
+    c = np.hypot(x - 3, y - 2)
+    s = (x - 3)
+
+    data1 = app.add_data(a={"x": x, "y": y, "c": c, "s": s})[0]
+
+    xx = np.random.normal(3, 1, 1000000)
+    yy = np.random.normal(2, 1.5, 1000000)
+
+    data2 = app.add_data(a={"x": xx, "y": yy})[0]
+
+    app.data_collection.add_link(LinkSame(data1.id['x'], data2.id['x']))
+    app.data_collection.add_link(LinkSame(data1.id['y'], data2.id['y']))
+
+    viewer = app.new_data_viewer(SimpleScatterViewer)
+    viewer.add_data(data1)
+    viewer.add_data(data2)
+
+    viewer.state.layers[0].cmap_mode = 'Linear'
+    viewer.state.layers[0].cmap_att = data1.id['c']
+    viewer.state.layers[0].cmap = plt.cm.viridis
+    viewer.state.layers[0].size_mode = 'Linear'
+    viewer.state.layers[0].size_att = data1.id['s']
+
+    viewer.state.layers[1].zorder = 0.5
+
+    app.data_collection.new_subset_group(label='subset1', subset_state=data1.id['x'] > 2)
+
+    return viewer.figure
+
+
 def test_reset_limits():
 
     data1 = Data(x=np.arange(1000), y=np.arange(1000) + 1000, label='data')