[WIP] Fix ImageInspectorTool event key (backward INcompatible)

chaco/tools/image_inspector_tool.py

@@ -31,7 +31,7 @@ class ImageInspectorTool(BaseTool):
 
     # Stores the value of self.visible when the mouse leaves the tool,
     # so that it can be restored when the mouse enters again.
-    _old_visible = Enum(None, True, False) #Trait(None, Bool(True))
+    _old_visible = Enum(None, True, False)
 
     def normal_key_pressed(self, event):
         if self.inspector_key.match(event):
@@ -64,19 +64,14 @@ def normal_mouse_move(self, event):
 
                 x_index, y_index = ndx
                 image_data = plot.value
+                new_value = {"indices": ndx,
+                             "data_value": image_data.data[y_index, x_index]}
                 if hasattr(plot, "_cached_mapped_image") and \
                        plot._cached_mapped_image is not None:
-                    self.new_value = \
-                        {"indices": ndx,
-                         "data_value": image_data.data[y_index, x_index],
-                         "color_value": plot._cached_mapped_image[y_index,
-                                                                  x_index]}
-
-                else:
-                    self.new_value = \
-                        {"indices": ndx,
-                         "color_value": image_data.data[y_index, x_index]}
+                    new_value["color_value"] = \
+                        plot._cached_mapped_image[y_index, x_index]
 
+                self.new_value = new_value
                 self.last_mouse_position = (event.x, event.y)
         return
 

examples/demo/basic/dataframe_scatter_inspector.py

@@ -0,0 +1,71 @@
+""" Overlay to display the data attached to a scatter point hovered over.
+"""
+import pandas as pd
+import numpy as np
+
+from traits.api import Callable, Enum, HasTraits, Instance, on_trait_change, \
+    Str
+from traitsui.api import View, Item
+from enable.api import ComponentEditor
+from chaco.api import Plot, ArrayPlotData, ScatterInspectorOverlay
+from chaco.tools.api import ScatterInspector
+from chaco.overlays.api import DataFrameScatterOverlay, TextBoxOverlay
+
+
+def _create_plot_component():
+    # Create a fake dataset from which 2 dimensions will be displayed in a
+    # scatter plot:
+    x = np.random.uniform(0.0, 10.0, 50)
+    y = np.random.uniform(0.0, 5.0, 50)
+    data = pd.DataFrame({"x": x, "y": y,
+                         "dataset": np.random.choice(list("abcdefg"), 50)})
+    plot_data = ArrayPlotData(x=x, y=y)
+    plot = Plot(plot_data)
+    scatter = plot.plot(("x", "y"), type="scatter")[0]
+
+    # Attach the inspector and its overlays
+    inspector = ScatterInspector(component=scatter)
+    scatter.tools.append(inspector)
+
+    text_overlay = DataframeScatterOverlay(component=plot,
+                                           inspector=inspector,
+                                           source_df=data,
+                                           bgcolor="black", alpha=0.6,
+                                           text_color="white",
+                                           border_color='none')
+    plot.overlays.append(text_overlay)
+
+    # Optional: add an overlay on the point to confirm what is hovered over
+    # Note that this overlay magically knows about hovered points by
+    # listening to renderer events rather than inspector events:
+    point_overlay = ScatterInspectorOverlay(component=scatter,
+                                            hover_color="red",
+                                            hover_marker_size=6)
+    scatter.overlays.append(point_overlay)
+    return plot
+
+
+# =============================================================================
+# Demo class that is used by the demo.py application.
+# =============================================================================
+
+size = (900, 500)
+title = "Tooltip demo"
+
+
+class Demo(HasTraits):
+    plot = Instance(Plot)
+
+    traits_view = View(
+        Item('plot', editor=ComponentEditor(size=size), show_label=False),
+        resizable=True, title=title
+    )
+
+    def _plot_default(self):
+        return _create_plot_component()
+
+
+demo = Demo()
+
+if __name__ == "__main__":
+    demo.configure_traits()