From 1f7a059846d6921ba4f34a3671d412093bbb37ab Mon Sep 17 00:00:00 2001
From: Aaron Ayres <aayres@enthought.com>
Date: Tue, 4 May 2021 12:00:40 -0500
Subject: [PATCH 01/25] make return types of map_screen consistent

---
 chaco/barplot.py       |  6 +++++-
 chaco/base_1d_plot.py  |  2 +-
 chaco/base_2d_plot.py  |  2 +-
 chaco/base_xy_plot.py  |  7 ++++++-
 chaco/data_view.py     |  9 +++++++--
 chaco/errorbar_plot.py |  2 +-
 chaco/grid_mapper.py   |  5 +++++
 chaco/horizon_plot.py  |  2 ++
 chaco/jitterplot.py    |  2 +-
 chaco/linear_mapper.py |  2 ++
 chaco/lineplot.py      |  4 ++--
 chaco/segment_plot.py  | 22 ++++++++++++++++++++++
 12 files changed, 55 insertions(+), 10 deletions(-)

diff --git a/chaco/barplot.py b/chaco/barplot.py
index 5749f5bf9..4e8b6363e 100644
--- a/chaco/barplot.py
+++ b/chaco/barplot.py
@@ -2,6 +2,7 @@
 """
 import logging
 
+import numpy as np
 from numpy import (
     array,
     compress,
@@ -166,9 +167,12 @@ def map_screen(self, data_array):
 
         Implements the AbstractPlotRenderer interface.
         """
+        # ensure data_array is an Nx2 ndarray
+        data_array = np.asarray(data_array)
+        data_array = data_array.reshape(-1,2)
         # data_array is Nx2 array
         if len(data_array) == 0:
-            return []
+            return np.empty(shape=(0,2))
         x_ary, y_ary = transpose(data_array)
         sx = self.index_mapper.map_screen(x_ary)
         sy = self.value_mapper.map_screen(y_ary)
diff --git a/chaco/base_1d_plot.py b/chaco/base_1d_plot.py
index 8fbb8f237..66dae6aea 100644
--- a/chaco/base_1d_plot.py
+++ b/chaco/base_1d_plot.py
@@ -111,7 +111,7 @@ def map_screen(self, data_array):
         """
         # data_array is 1D array of length N
         if len(data_array) == 0:
-            return []
+            return empty(shape=(0,))
         return asarray(self.index_mapper.map_screen(data_array))
 
     def map_data(self, screen_pts):
diff --git a/chaco/base_2d_plot.py b/chaco/base_2d_plot.py
index 469b3a43c..082053e8a 100644
--- a/chaco/base_2d_plot.py
+++ b/chaco/base_2d_plot.py
@@ -111,7 +111,7 @@ def map_screen(self, data_pts):
         """
         # data_pts is Nx2 array
         if len(data_pts) == 0:
-            return []
+            return np.empty(shape=(0,2))
         return asarray(self.index_mapper.map_screen(data_pts))
 
     def map_data(self, screen_pts):
diff --git a/chaco/base_xy_plot.py b/chaco/base_xy_plot.py
index d73571132..f287a8ec0 100644
--- a/chaco/base_xy_plot.py
+++ b/chaco/base_xy_plot.py
@@ -1,6 +1,7 @@
 """ Defines the base class for XY plots.
 """
 from math import sqrt
+import numpy as np
 from numpy import around, array, isnan, transpose
 
 # Enthought library imports
@@ -343,9 +344,13 @@ def map_screen(self, data_array):
 
         Implements the AbstractPlotRenderer interface.
         """
+        # ensure data_array is an Nx2 ndarray
+        data_array = np.asarray(data_array)
+        data_array = data_array.reshape(-1,2)
+
         # data_array is Nx2 array
         if len(data_array) == 0:
-            return []
+            return np.empty(shape=(0,2))
 
         x_ary, y_ary = transpose(data_array)
 
diff --git a/chaco/data_view.py b/chaco/data_view.py
index 53c300fef..3fd4ceaa3 100644
--- a/chaco/data_view.py
+++ b/chaco/data_view.py
@@ -1,6 +1,7 @@
 """ Defines the DataView class, and associated property traits and property
 functions.
 """
+import numpy as np
 from numpy import array, transpose
 
 from traits.api import Bool, Enum, Instance, Property
@@ -232,9 +233,13 @@ def map_screen(self, data_array):
         """Maps an array of data points to screen space and returns an array
         of screen space points.
         """
-        # data_array is Nx2 array
+
+        # ensure data_array is an Nx2 ndarray
+        data_array = np.asarray(data_array)
+        data_array = data_array.reshape(-1,2)
+
         if len(data_array) == 0:
-            return []
+            return np.empty(shape=(0,2))
         x_ary, y_ary = transpose(data_array)
         sx = self.index_mapper.map_screen(x_ary)
         sy = self.value_mapper.map_screen(y_ary)
diff --git a/chaco/errorbar_plot.py b/chaco/errorbar_plot.py
index 94c80d18e..b0e4fcb37 100644
--- a/chaco/errorbar_plot.py
+++ b/chaco/errorbar_plot.py
@@ -39,7 +39,7 @@ def map_screen(self, data_array):
         or (y, xlow, xhigh) depending on self.orientation.
         """
         if len(data_array) == 0:
-            return []
+            return np.empty(shape=(0,2))
         elif data_array.shape[1] == 2:
             return LinePlot.map_screen(self, data_array)
         else:
diff --git a/chaco/grid_mapper.py b/chaco/grid_mapper.py
index 9a810a03e..9d1f5a3bd 100644
--- a/chaco/grid_mapper.py
+++ b/chaco/grid_mapper.py
@@ -7,6 +7,7 @@
 from contextlib import contextmanager
 
 # Major library imports
+import numpy as np
 from numpy import column_stack, transpose
 
 # Enthought library imports
@@ -116,6 +117,10 @@ def map_screen(self, data_pts):
 
         Maps values from data space into screen space.
         """
+        # ensure data_array is an Nx2 ndarray
+        data_pts = np.asarray(data_pts)
+        data_pts = data_pts.reshape(-1,2)
+    
         xs, ys = transpose(data_pts)
         screen_xs = self._xmapper.map_screen(xs)
         screen_ys = self._ymapper.map_screen(ys)
diff --git a/chaco/horizon_plot.py b/chaco/horizon_plot.py
index 069b04888..7e1e7713b 100644
--- a/chaco/horizon_plot.py
+++ b/chaco/horizon_plot.py
@@ -20,6 +20,8 @@ def map_screen(self, data_array):
                 return array([self.low_pos])
         else:
             # Scale the data by the number of bands
+            if not isinstance(data_array, ndarray):
+                data_array = array(data_array, ndmin=1)
             return (
                 data_array * self.bands - self.range.low
             ) * self._scale + self.low_pos
diff --git a/chaco/jitterplot.py b/chaco/jitterplot.py
index 79a56e654..dbfe561c1 100644
--- a/chaco/jitterplot.py
+++ b/chaco/jitterplot.py
@@ -36,7 +36,7 @@ def map_screen(self, data_array):
         Implements the AbstractPlotRenderer interface.
         """
         if len(data_array) == 0:
-            return np.zeros(0)
+            return np.empty(shape=(0,))
 
         if self._screen_cache_valid:
             sm = self._cached_screen_map
diff --git a/chaco/linear_mapper.py b/chaco/linear_mapper.py
index 16dd61e46..7f48baf79 100644
--- a/chaco/linear_mapper.py
+++ b/chaco/linear_mapper.py
@@ -49,6 +49,8 @@ def map_screen(self, data_array):
             else:
                 return array([self.low_pos])
         else:
+            if not isinstance(data_array, ndarray):
+                data_array = array(data_array, ndmin=1)
             return (data_array - self.range.low) * self._scale + self.low_pos
 
     def map_data(self, screen_val):
diff --git a/chaco/lineplot.py b/chaco/lineplot.py
index 6a7861521..a12c6a2b8 100644
--- a/chaco/lineplot.py
+++ b/chaco/lineplot.py
@@ -114,8 +114,8 @@ def hittest(self, screen_pt, threshold=7.0, return_distance=False):
             if return_distance:
                 scrn_pt = self.map_screen(data_pt)
                 dist = sqrt(
-                    (screen_pt[0] - scrn_pt[0]) ** 2
-                    + (screen_pt[1] - scrn_pt[1]) ** 2
+                    (screen_pt[0] - scrn_pt[0, 0]) ** 2
+                    + (screen_pt[1] - scrn_pt[0, 1]) ** 2
                 )
                 return (data_pt[0], data_pt[1], dist)
             else:
diff --git a/chaco/segment_plot.py b/chaco/segment_plot.py
index 633ba05e2..613b3cd97 100644
--- a/chaco/segment_plot.py
+++ b/chaco/segment_plot.py
@@ -132,6 +132,28 @@ def hittest(self, *args, **kwargs):
     def map_index(self, *args, **kwargs):
         raise NotImplementedError()
 
+    def map_screen(self, data_array):
+        """Maps an Nx2x2 array of data points into screen space and returns it
+        as an array.
+
+        Implements the AbstractPlotRenderer interface.
+        """
+        # ensure data_array is an Nx2x2 ndarray
+        data_array = np.asarray(data_array)
+        data_array = data_array.reshape(-1,2, 2)
+
+        if len(data_array) == 0:
+            return np.empty(shape=(0, 2, 2))
+
+        x_ary, y_ary = np.transpose(data_array)
+
+        sx = self.index_mapper.map_screen(x_ary)
+        sy = self.value_mapper.map_screen(y_ary)
+        if self.orientation == "h":
+            return np.transpose(np.array((sx, sy)))
+        else:
+            return np.transpose(np.array((sy, sx)))
+
     def _gather_points(self):
         """Collects the data points that are within the bounds of the plot and
         caches them.

From 9e219a04377cbf35191b86f360750184c7cf56c9 Mon Sep 17 00:00:00 2001
From: Aaron Ayres <aayres@enthought.com>
Date: Tue, 4 May 2021 12:10:55 -0500
Subject: [PATCH 02/25] use np for numpy

---
 chaco/barplot.py      | 36 +++++++++++++--------------------
 chaco/base_xy_plot.py | 21 ++++++++++----------
 chaco/data_view.py    |  9 ++++-----
 chaco/grid_mapper.py  |  9 ++++-----
 chaco/log_mapper.py   | 46 ++++++++++++++++---------------------------
 5 files changed, 49 insertions(+), 72 deletions(-)

diff --git a/chaco/barplot.py b/chaco/barplot.py
index 4e8b6363e..5e017268b 100644
--- a/chaco/barplot.py
+++ b/chaco/barplot.py
@@ -3,15 +3,7 @@
 import logging
 
 import numpy as np
-from numpy import (
-    array,
-    compress,
-    column_stack,
-    invert,
-    isnan,
-    transpose,
-    zeros,
-)
+
 from traits.api import (
     Any,
     Bool,
@@ -173,14 +165,14 @@ def map_screen(self, data_array):
         # data_array is Nx2 array
         if len(data_array) == 0:
             return np.empty(shape=(0,2))
-        x_ary, y_ary = transpose(data_array)
+        x_ary, y_ary = np.transpose(data_array)
         sx = self.index_mapper.map_screen(x_ary)
         sy = self.value_mapper.map_screen(y_ary)
 
         if self.orientation == "h":
-            return transpose(array((sx, sy)))
+            return np.transpose(np.array((sx, sy)))
         else:
-            return transpose(array((sy, sx)))
+            return np.transpose(np.array((sy, sx)))
 
     def map_data(self, screen_pt):
         """Maps a screen space point into the "index" space of the plot.
@@ -224,7 +216,7 @@ def map_index(
         x = index_data[ndx]
         y = value_data[ndx]
 
-        result = self.map_screen(array([[x, y]]))
+        result = self.map_screen(np.array([[x, y]]))
         if result is None:
             return None
 
@@ -257,7 +249,7 @@ def _gather_points(self):
                 "Chaco: using empty dataset; index_len=%d, value_len=%d."
                 % (len(index), len(value))
             )
-            self._cached_data_pts = array([])
+            self._cached_data_pts = np.array([])
             self._cache_valid = True
             return
 
@@ -270,17 +262,17 @@ def _gather_points(self):
         #              index_range_mask & value_range_mask
 
         index_range_mask = self.index_mapper.range.mask_data(index)
-        nan_mask = invert(isnan(index_mask))
+        nan_mask = np.invert(np.isnan(index_mask))
         point_mask = index_mask & nan_mask & index_range_mask
 
         if self.starting_value is None:
-            starting_values = zeros(len(index))
+            starting_values = np.zeros(len(index))
         else:
             starting_values = self.starting_value.get_data()
 
         if self.bar_width_type == "data":
             half_width = self.bar_width / 2.0
-            points = column_stack(
+            points = np.column_stack(
                 (
                     index - half_width,
                     index + half_width,
@@ -289,8 +281,8 @@ def _gather_points(self):
                 )
             )
         else:
-            points = column_stack((index, starting_values, value))
-        self._cached_data_pts = compress(point_mask, points, axis=0)
+            points = np.column_stack((index, starting_values, value))
+        self._cached_data_pts = np.compress(point_mask, points, axis=0)
 
         self._cache_valid = True
 
@@ -325,7 +317,7 @@ def _draw_plot(self, gc, view_bounds=None, mode="normal"):
                 upper_right_pts[:, 0] += half_width
 
             bounds = upper_right_pts - lower_left_pts
-            gc.rects(column_stack((lower_left_pts, bounds)))
+            gc.rects(np.column_stack((lower_left_pts, bounds)))
             gc.draw_path()
 
     def _draw_default_axes(self, gc):
@@ -341,10 +333,10 @@ def _draw_default_axes(self, gc):
                 if (range.low < 0) and (range.high > 0):
                     if range == self.index_mapper.range:
                         dual = self.value_mapper.range
-                        data_pts = array([[0.0, dual.low], [0.0, dual.high]])
+                        data_pts = np.array([[0.0, dual.low], [0.0, dual.high]])
                     else:
                         dual = self.index_mapper.range
-                        data_pts = array([[dual.low, 0.0], [dual.high, 0.0]])
+                        data_pts = np.array([[dual.low, 0.0], [dual.high, 0.0]])
                     start, end = self.map_screen(data_pts)
                     gc.move_to(int(start[0]) + 0.5, int(start[1]) + 0.5)
                     gc.line_to(int(end[0]) + 0.5, int(end[1]) + 0.5)
diff --git a/chaco/base_xy_plot.py b/chaco/base_xy_plot.py
index f287a8ec0..ed44ff3be 100644
--- a/chaco/base_xy_plot.py
+++ b/chaco/base_xy_plot.py
@@ -2,7 +2,6 @@
 """
 from math import sqrt
 import numpy as np
-from numpy import around, array, isnan, transpose
 
 # Enthought library imports
 from enable.api import black_color_trait
@@ -352,14 +351,14 @@ def map_screen(self, data_array):
         if len(data_array) == 0:
             return np.empty(shape=(0,2))
 
-        x_ary, y_ary = transpose(data_array)
+        x_ary, y_ary = np.transpose(data_array)
 
         sx = self.index_mapper.map_screen(x_ary)
         sy = self.value_mapper.map_screen(y_ary)
         if self.orientation == "h":
-            return transpose(array((sx, sy)))
+            return np.transpose(np.array((sx, sy)))
         else:
-            return transpose(array((sy, sx)))
+            return np.transpose(np.array((sy, sx)))
 
     def map_data(self, screen_pt, all_values=False):
         """Maps a screen space point into the "index" space of the plot.
@@ -373,7 +372,7 @@ def map_data(self, screen_pt, all_values=False):
         if self.orientation == "v":
             x, y = y, x
         if all_values:
-            return array(
+            return np.array(
                 (self.index_mapper.map_data(x), self.value_mapper.map_data(y))
             )
         else:
@@ -442,14 +441,14 @@ def map_index(
 
         x = index_data[ndx]
         y = value_data[ndx]
-        if isnan(x) or isnan(y):
+        if np.isnan(x) or np.isnan(y):
             return None
 
         # transform x,y in a 1x2 array, which is the preferred format of
         # map_screen. this makes it robust against differences in
         # the map_screen methods of logmapper and linearmapper
         # when passed a scalar
-        xy = array([[x, y]])
+        xy = np.array([[x, y]])
         sx, sy = self.map_screen(xy).T
         if index_only and (threshold == 0.0 or screen_pt[0] - sx < threshold):
             return ndx
@@ -501,13 +500,13 @@ def _draw_default_axes(self, gc):
                 if (range.low < 0) and (range.high > 0):
                     if range == self.index_mapper.range:
                         dual = self.value_mapper.range
-                        data_pts = array([[0.0, dual.low], [0.0, dual.high]])
+                        data_pts = np.array([[0.0, dual.low], [0.0, dual.high]])
                     else:
                         dual = self.index_mapper.range
-                        data_pts = array([[dual.low, 0.0], [dual.high, 0.0]])
+                        data_pts = np.array([[dual.low, 0.0], [dual.high, 0.0]])
                     start, end = self.map_screen(data_pts)
-                    start = around(start)
-                    end = around(end)
+                    start = np.around(start)
+                    end = np.around(end)
                     gc.move_to(int(start[0]), int(start[1]))
                     gc.line_to(int(end[0]), int(end[1]))
                     gc.stroke_path()
diff --git a/chaco/data_view.py b/chaco/data_view.py
index 3fd4ceaa3..e6b5720ed 100644
--- a/chaco/data_view.py
+++ b/chaco/data_view.py
@@ -2,7 +2,6 @@
 functions.
 """
 import numpy as np
-from numpy import array, transpose
 
 from traits.api import Bool, Enum, Instance, Property
 from enable.api import color_table
@@ -240,13 +239,13 @@ def map_screen(self, data_array):
 
         if len(data_array) == 0:
             return np.empty(shape=(0,2))
-        x_ary, y_ary = transpose(data_array)
+        x_ary, y_ary = np.transpose(data_array)
         sx = self.index_mapper.map_screen(x_ary)
         sy = self.value_mapper.map_screen(y_ary)
         if self.orientation == "h":
-            return transpose(array((sx, sy)))
+            return np.transpose(np.array((sx, sy)))
         else:
-            return transpose(array((sy, sx)))
+            return np.transpose(np.array((sy, sx)))
 
     def map_data(self, screen_pt):
         """Maps a screen space point into the 2D data space of this plot.
@@ -256,7 +255,7 @@ def map_data(self, screen_pt):
         # At some point it would be good to change the DataView to use
         # the GridMapper, and then use its map_data() method.
         x, y = screen_pt
-        return array(
+        return np.array(
             (self.index_mapper.map_data(x), self.value_mapper.map_data(y))
         )
 
diff --git a/chaco/grid_mapper.py b/chaco/grid_mapper.py
index 9d1f5a3bd..b46b081ae 100644
--- a/chaco/grid_mapper.py
+++ b/chaco/grid_mapper.py
@@ -8,7 +8,6 @@
 
 # Major library imports
 import numpy as np
-from numpy import column_stack, transpose
 
 # Enthought library imports
 from traits.api import Bool, DelegatesTo, Instance, Float, Property
@@ -121,10 +120,10 @@ def map_screen(self, data_pts):
         data_pts = np.asarray(data_pts)
         data_pts = data_pts.reshape(-1,2)
     
-        xs, ys = transpose(data_pts)
+        xs, ys = np.transpose(data_pts)
         screen_xs = self._xmapper.map_screen(xs)
         screen_ys = self._ymapper.map_screen(ys)
-        screen_pts = column_stack([screen_xs, screen_ys])
+        screen_pts = np.column_stack([screen_xs, screen_ys])
         return screen_pts
 
     def map_data(self, screen_pts):
@@ -132,10 +131,10 @@ def map_data(self, screen_pts):
 
         Maps values from screen space into data space.
         """
-        screen_xs, screen_ys = transpose(screen_pts)
+        screen_xs, screen_ys = np.transpose(screen_pts)
         xs = self._xmapper.map_data(screen_xs)
         ys = self._ymapper.map_data(screen_ys)
-        data_pts = column_stack([xs, ys])
+        data_pts = np.column_stack([xs, ys])
         return data_pts
 
     def map_data_array(self, screen_pts):
diff --git a/chaco/log_mapper.py b/chaco/log_mapper.py
index 4316576dd..7aff2408e 100644
--- a/chaco/log_mapper.py
+++ b/chaco/log_mapper.py
@@ -1,18 +1,6 @@
 """ Defines the LogMapper and InvalidDataRangeException classes.
 """
 # Major library imports
-from numpy import (
-    array,
-    isnan,
-    log,
-    log10,
-    exp,
-    zeros,
-    sometrue,
-    floor,
-    ceil,
-    ndarray,
-)
 import numpy as np
 
 # Enthought library imports
@@ -58,8 +46,8 @@ def map_screen(self, data_array):
         Overrides AbstractMapper. Maps values from data space to screen space.
         """
         # Ensure that data_array is actually an array.
-        if not isinstance(data_array, ndarray):
-            data_array = array(data_array, ndmin=1)
+        if not isinstance(data_array, np.ndarray):
+            data_array = np.array(data_array, ndmin=1)
         # First convert to a [0,1] space, then to the screen space.
         if not self._cache_valid:
             self._compute_scale()
@@ -68,15 +56,15 @@ def map_screen(self, data_array):
         else:
             try:
                 with np.errstate(invalid="ignore"):
-                    mask = (data_array <= LOG_MINIMUM) | isnan(data_array)
-                if sometrue(mask):
-                    data_array = array(data_array, copy=True, ndmin=1)
+                    mask = (data_array <= LOG_MINIMUM) | np.isnan(data_array)
+                if np.sometrue(mask):
+                    data_array = np.array(data_array, copy=True, ndmin=1)
                     data_array[mask] = self.fill_value
                 intermediate = (
-                    log(data_array) - self._inter_offset
+                    np.log(data_array) - self._inter_offset
                 ) / self._inter_scale
             except ValueError:
-                intermediate = zeros(len(data_array))
+                intermediate = np.zeros(len(data_array))
 
         result = intermediate * self._screen_scale + self._screen_offset
         return result
@@ -89,10 +77,10 @@ def map_data(self, screen_val):
         if not self._cache_valid:
             self._compute_scale()
         if self._null_screen_range or self._null_data_range:
-            return array([self.range.low])
+            return np.array([self.range.low])
         # First convert to a [0,1] space, then to the data space
         intermediate = (screen_val - self._screen_offset) / self._screen_scale
-        return exp(self._inter_scale * intermediate + self._inter_offset)
+        return np.exp(self._inter_scale * intermediate + self._inter_offset)
 
     def map_data_array(self, screen_vals):
         return self.map_data(screen_vals)
@@ -119,12 +107,12 @@ def _get_safe_scale(self, range):
                 low = 1.0
                 high = 10.0
             else:
-                log_val = log10(low)
-                low = pow(10, floor(log_val))
-                if ceil(log_val) != floor(log_val):
-                    high = pow(10, ceil(log_val))
+                log_val = np.log10(low)
+                low = pow(10, np.floor(log_val))
+                if np.ceil(log_val) != np.floor(log_val):
+                    high = pow(10, np.ceil(log_val))
                 else:
-                    high = pow(10, ceil(log_val) + 1)
+                    high = pow(10, np.ceil(log_val) + 1)
 
         return (low, high)
 
@@ -147,11 +135,11 @@ def _compute_scale(self):
             self._null_data_range = True
         else:
             if low == LOG_MINIMUM:
-                self._inter_scale = log(high)
+                self._inter_scale = np.log(high)
                 self._inter_offset = 0.0
             else:
-                self._inter_scale = log(high) - log(low)
-                self._inter_offset = log(low)
+                self._inter_scale = np.log(high) - np.log(low)
+                self._inter_offset = np.log(low)
             self._screen_scale = screen_range
             self._screen_offset = self.low_pos
 

From 8eedf6c964aec71600ce1fbc279f49176186994d Mon Sep 17 00:00:00 2001
From: Aaron Ayres <aayres@enthought.com>
Date: Tue, 4 May 2021 12:27:08 -0500
Subject: [PATCH 03/25] flake8

---
 chaco/base_xy_plot.py  | 12 ++++++++----
 chaco/errorbar_plot.py |  4 ++--
 chaco/grid_mapper.py   |  4 ++--
 chaco/segment_plot.py  |  2 +-
 4 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/chaco/base_xy_plot.py b/chaco/base_xy_plot.py
index ed44ff3be..b7802c727 100644
--- a/chaco/base_xy_plot.py
+++ b/chaco/base_xy_plot.py
@@ -345,11 +345,11 @@ def map_screen(self, data_array):
         """
         # ensure data_array is an Nx2 ndarray
         data_array = np.asarray(data_array)
-        data_array = data_array.reshape(-1,2)
+        data_array = data_array.reshape(-1, 2)
 
         # data_array is Nx2 array
         if len(data_array) == 0:
-            return np.empty(shape=(0,2))
+            return np.empty(shape=(0, 2))
 
         x_ary, y_ary = np.transpose(data_array)
 
@@ -500,10 +500,14 @@ def _draw_default_axes(self, gc):
                 if (range.low < 0) and (range.high > 0):
                     if range == self.index_mapper.range:
                         dual = self.value_mapper.range
-                        data_pts = np.array([[0.0, dual.low], [0.0, dual.high]])
+                        data_pts = np.array(
+                            [[0.0, dual.low], [0.0, dual.high]]
+                        )
                     else:
                         dual = self.index_mapper.range
-                        data_pts = np.array([[dual.low, 0.0], [dual.high, 0.0]])
+                        data_pts = np.array(
+                            [[dual.low, 0.0], [dual.high, 0.0]]
+                        )
                     start, end = self.map_screen(data_pts)
                     start = np.around(start)
                     end = np.around(end)
diff --git a/chaco/errorbar_plot.py b/chaco/errorbar_plot.py
index b0e4fcb37..9ef4a560e 100644
--- a/chaco/errorbar_plot.py
+++ b/chaco/errorbar_plot.py
@@ -1,5 +1,5 @@
 # Major library imports
-from numpy import column_stack, compress, invert, isnan, transpose
+from numpy import column_stack, compress, empty, invert, isnan, transpose
 import logging
 
 # Enthought library imports
@@ -39,7 +39,7 @@ def map_screen(self, data_array):
         or (y, xlow, xhigh) depending on self.orientation.
         """
         if len(data_array) == 0:
-            return np.empty(shape=(0,2))
+            return empty(shape=(0, 2))
         elif data_array.shape[1] == 2:
             return LinePlot.map_screen(self, data_array)
         else:
diff --git a/chaco/grid_mapper.py b/chaco/grid_mapper.py
index b46b081ae..d192545a1 100644
--- a/chaco/grid_mapper.py
+++ b/chaco/grid_mapper.py
@@ -118,8 +118,8 @@ def map_screen(self, data_pts):
         """
         # ensure data_array is an Nx2 ndarray
         data_pts = np.asarray(data_pts)
-        data_pts = data_pts.reshape(-1,2)
-    
+        data_pts = data_pts.reshape(-1, 2)
+
         xs, ys = np.transpose(data_pts)
         screen_xs = self._xmapper.map_screen(xs)
         screen_ys = self._ymapper.map_screen(ys)
diff --git a/chaco/segment_plot.py b/chaco/segment_plot.py
index 613b3cd97..e49435235 100644
--- a/chaco/segment_plot.py
+++ b/chaco/segment_plot.py
@@ -140,7 +140,7 @@ def map_screen(self, data_array):
         """
         # ensure data_array is an Nx2x2 ndarray
         data_array = np.asarray(data_array)
-        data_array = data_array.reshape(-1,2, 2)
+        data_array = data_array.reshape(-1, 2, 2)
 
         if len(data_array) == 0:
             return np.empty(shape=(0, 2, 2))

From 32f6c07c9e4c548dd118c42f0fe0bf9a9cbcf8f9 Mon Sep 17 00:00:00 2001
From: Aaron Ayres <aayres@enthought.com>
Date: Tue, 4 May 2021 12:31:37 -0500
Subject: [PATCH 04/25] update cursor_tool.py to expect Nx2 array output from
 map_screen

---
 chaco/tools/cursor_tool.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/chaco/tools/cursor_tool.py b/chaco/tools/cursor_tool.py
index 4002861d1..86cc3eacb 100644
--- a/chaco/tools/cursor_tool.py
+++ b/chaco/tools/cursor_tool.py
@@ -190,7 +190,7 @@ def draw(self, gc, view_bounds=None):
         if plot is None:
             return
 
-        sx, sy = plot.map_screen(self.current_position)
+        sx, sy = plot.map_screen(self.current_position)[0]
         orientation = plot.orientation
 
         if orientation == "h" and sx is not None:
@@ -211,7 +211,7 @@ def is_draggable(self, x, y):
         plot = self.component
         if plot is not None:
             orientation = plot.orientation
-            sx, sy = plot.map_screen(self.current_position)
+            sx, sy = plot.map_screen(self.current_position)[0]
             if orientation == "h" and numpy.abs(sx - x) <= self.threshold:
                 return True
             elif orientation == "v" and numpy.abs(sy - y) <= self.threshold:

From 886198458ac74c37fcea9edacf12a395100ae4da Mon Sep 17 00:00:00 2001
From: Aaron Ayres <aayres@enthought.com>
Date: Tue, 4 May 2021 15:52:06 -0500
Subject: [PATCH 05/25] expect correct return type

---
 chaco/barplot.py               | 2 +-
 chaco/tools/data_label_tool.py | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/chaco/barplot.py b/chaco/barplot.py
index 5e017268b..2299c3eaa 100644
--- a/chaco/barplot.py
+++ b/chaco/barplot.py
@@ -337,7 +337,7 @@ def _draw_default_axes(self, gc):
                     else:
                         dual = self.index_mapper.range
                         data_pts = np.array([[dual.low, 0.0], [dual.high, 0.0]])
-                    start, end = self.map_screen(data_pts)
+                    start, end = self.map_screen(data_pts)[0]
                     gc.move_to(int(start[0]) + 0.5, int(start[1]) + 0.5)
                     gc.line_to(int(end[0]) + 0.5, int(end[1]) + 0.5)
                     gc.stroke_path()
diff --git a/chaco/tools/data_label_tool.py b/chaco/tools/data_label_tool.py
index dabf0242f..582f20837 100644
--- a/chaco/tools/data_label_tool.py
+++ b/chaco/tools/data_label_tool.py
@@ -61,7 +61,7 @@ def drag_start(self, event):
         """
         if self.component:
             label = self.component
-            pointx, pointy = label.component.map_screen(label.data_point)
+            pointx, pointy = label.component.map_screen(label.data_point)[0]
             self._original_offset = (label.x - pointx, label.y - pointy)
             event.window.set_mouse_owner(self, event.net_transform())
             event.handled = True

From 74175b8ea3a3eeda051feb44451bd98d63908a5b Mon Sep 17 00:00:00 2001
From: Aaron Ayres <aayres@enthought.com>
Date: Wed, 5 May 2021 13:46:21 -0500
Subject: [PATCH 06/25] add a regression test for 272

---
 chaco/tests/test_plot.py | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/chaco/tests/test_plot.py b/chaco/tests/test_plot.py
index b7be564f5..5d2559683 100644
--- a/chaco/tests/test_plot.py
+++ b/chaco/tests/test_plot.py
@@ -1,5 +1,6 @@
 import unittest
 
+import numpy as np
 from numpy import alltrue, arange, array
 
 from enable.api import ComponentEditor
@@ -109,6 +110,25 @@ def test_text_plot(self):
         actual = gc.bmp_array[:, :, :]
         self.assertFalse(alltrue(actual == 255))
 
+    def check_map_screen(self, renderer):
+        arr = arange(10)
+        data = ArrayPlotData(x=arr, y=arr)
+        plot = Plot(data)
+        plot_renderer = plot.add_xy_plot(
+            'x', 'y', plot.renderer_map[renderer]
+        )[0]
+        
+        screen_point = plot_renderer.map_screen((-1, 1))
+
+        self.assertEqual(type(screen_point), np.ndarray)
+        self.assertEqual(screen_point.shape, (1,2))
+
+    # serves as a regression test for enthought/chaco#272
+    def test_map_screen(self):
+        renderers = ["line", "scatter"]
+        for renderer in renderers:
+            self.check_map_screen(renderer)
+
 
 class EmptyLinePlot(HasTraits):
     plot = Instance(Plot)

From 9c85c5ac2ada15b9f4a80bcd9283431c3cee947e Mon Sep 17 00:00:00 2001
From: Aaron Ayres <aayres@enthought.com>
Date: Wed, 5 May 2021 13:54:46 -0500
Subject: [PATCH 07/25] run same test on a couple more renderers

---
 chaco/tests/test_plot.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/chaco/tests/test_plot.py b/chaco/tests/test_plot.py
index 5d2559683..e01f57476 100644
--- a/chaco/tests/test_plot.py
+++ b/chaco/tests/test_plot.py
@@ -124,8 +124,8 @@ def check_map_screen(self, renderer):
         self.assertEqual(screen_point.shape, (1,2))
 
     # serves as a regression test for enthought/chaco#272
-    def test_map_screen(self):
-        renderers = ["line", "scatter"]
+    def test_xy_plot_map_screen(self):
+        renderers = ["line", "scatter", "bar", "polygon"]
         for renderer in renderers:
             self.check_map_screen(renderer)
 

From ad93274d8605cef247ea5328a143cd2643da9a6a Mon Sep 17 00:00:00 2001
From: Aaron Ayres <aayres@enthought.com>
Date: Wed, 5 May 2021 14:03:28 -0500
Subject: [PATCH 08/25] add a test for SegmentPlot which does its own thing

---
 chaco/tests/test_plot.py | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/chaco/tests/test_plot.py b/chaco/tests/test_plot.py
index e01f57476..4301b0e52 100644
--- a/chaco/tests/test_plot.py
+++ b/chaco/tests/test_plot.py
@@ -110,6 +110,19 @@ def test_text_plot(self):
         actual = gc.bmp_array[:, :, :]
         self.assertFalse(alltrue(actual == 255))
 
+    def test_segment_plot_map_screen(self):
+        x = arange(10)
+        y = arange(1, 11)
+        data = ArrayPlotData(x=x, y=y)
+        plot = Plot(data)
+        plot_renderer = plot.plot(("x", "y"), "segment")[0]
+
+        screen_point = plot_renderer.map_screen([(0, 1), (1, 2)])
+
+        self.assertEqual(type(screen_point), np.ndarray)
+        self.assertEqual(screen_point.shape, (1,2,2))
+
+
     def check_map_screen(self, renderer):
         arr = arange(10)
         data = ArrayPlotData(x=arr, y=arr)

From 527bdb9a220592ed806f5f5f3ee15509c9419c53 Mon Sep 17 00:00:00 2001
From: Aaron Ayres <aayres@enthought.com>
Date: Wed, 5 May 2021 14:26:52 -0500
Subject: [PATCH 09/25] add explicit map_screen specific test for ImagePlot

---
 chaco/tests/test_image_plot.py | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/chaco/tests/test_image_plot.py b/chaco/tests/test_image_plot.py
index 9bed8f7cb..7aa3546ed 100644
--- a/chaco/tests/test_image_plot.py
+++ b/chaco/tests/test_image_plot.py
@@ -185,6 +185,21 @@ def test_vertical_bottom_right(self):
             RGB, (IMAGE.T)[::-1, ::-1], origin="bottom right", orientation="v"
         )
 
+    def test_map_screen(self):
+        data_source = ImageData(data=RGB)
+        index, index_mapper = get_image_index_and_mapper(RGB)
+        renderer = ImagePlot(
+            value=data_source,
+            index=index,
+            index_mapper=index_mapper,
+        )
+
+        # ImagePlot map screen is used tto find the screen_bbox, not on data
+        # itself.
+        screen_pt = renderer.map_screen([(0, 0)])
+        self.assertEqual(type(screen_pt), np.ndarray)
+        self.assertEqual(screen_pt.shape, (1,2))
+
     # regression test for enthought/chaco#528
     @unittest.skipIf(is_null or is_qt4(), "Skip on 'null' or 'qt4' toolkit")
     def test_resize_to_zero(self):

From db31b7b3df9ee04fce53539698ce070d27605b65 Mon Sep 17 00:00:00 2001
From: Aaron Ayres <aayres@enthought.com>
Date: Wed, 5 May 2021 14:30:53 -0500
Subject: [PATCH 10/25] test map screen on no data points ImagePlot

---
 chaco/base_2d_plot.py          | 4 ++--
 chaco/tests/test_image_plot.py | 4 ++++
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/chaco/base_2d_plot.py b/chaco/base_2d_plot.py
index 082053e8a..9cec58048 100644
--- a/chaco/base_2d_plot.py
+++ b/chaco/base_2d_plot.py
@@ -1,7 +1,7 @@
 """ Defines the base class for 2-D plots.
 """
 # Standard library imports
-from numpy import asarray, isnan
+from numpy import asarray, empty, isnan
 
 # Enthought library imports.
 from traits.api import Enum, Event, Instance, Property, Range, Trait
@@ -111,7 +111,7 @@ def map_screen(self, data_pts):
         """
         # data_pts is Nx2 array
         if len(data_pts) == 0:
-            return np.empty(shape=(0,2))
+            return empty(shape=(0,2))
         return asarray(self.index_mapper.map_screen(data_pts))
 
     def map_data(self, screen_pts):
diff --git a/chaco/tests/test_image_plot.py b/chaco/tests/test_image_plot.py
index 7aa3546ed..1d150c221 100644
--- a/chaco/tests/test_image_plot.py
+++ b/chaco/tests/test_image_plot.py
@@ -200,6 +200,10 @@ def test_map_screen(self):
         self.assertEqual(type(screen_pt), np.ndarray)
         self.assertEqual(screen_pt.shape, (1,2))
 
+        screen_pt = renderer.map_screen([])
+        self.assertEqual(type(screen_pt), np.ndarray)
+        self.assertEqual(screen_pt.shape, (0,2))
+
     # regression test for enthought/chaco#528
     @unittest.skipIf(is_null or is_qt4(), "Skip on 'null' or 'qt4' toolkit")
     def test_resize_to_zero(self):

From 206bc724209274a8ad244805b50f52e7c66297a2 Mon Sep 17 00:00:00 2001
From: Aaron Ayres <aayres@enthought.com>
Date: Wed, 5 May 2021 14:33:31 -0500
Subject: [PATCH 11/25] have Plot tests also test map_screen on no data points

---
 chaco/scatterplot.py     | 3 ++-
 chaco/tests/test_plot.py | 5 +++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/chaco/scatterplot.py b/chaco/scatterplot.py
index e3cb16f03..b5d73b61d 100644
--- a/chaco/scatterplot.py
+++ b/chaco/scatterplot.py
@@ -11,6 +11,7 @@
     array,
     asarray,
     column_stack,
+    empty,
     isfinite,
     isnan,
     nanargmin,
@@ -289,7 +290,7 @@ def map_screen(self, data_array):
         """
         # data_array is Nx2 array
         if len(data_array) == 0:
-            return []
+            return empty(shape=(0,2))
 
         data_array = asarray(data_array)
         if len(data_array.shape) == 1:
diff --git a/chaco/tests/test_plot.py b/chaco/tests/test_plot.py
index 4301b0e52..fe6dd94ff 100644
--- a/chaco/tests/test_plot.py
+++ b/chaco/tests/test_plot.py
@@ -136,6 +136,11 @@ def check_map_screen(self, renderer):
         self.assertEqual(type(screen_point), np.ndarray)
         self.assertEqual(screen_point.shape, (1,2))
 
+        screen_point = plot_renderer.map_screen([])
+
+        self.assertEqual(type(screen_point), np.ndarray)
+        self.assertEqual(screen_point.shape, (0,2))
+
     # serves as a regression test for enthought/chaco#272
     def test_xy_plot_map_screen(self):
         renderers = ["line", "scatter", "bar", "polygon"]

From d85658a0ce0e47565569fa6a4f23bcebb14fa965 Mon Sep 17 00:00:00 2001
From: Aaron Ayres <aayres@enthought.com>
Date: Wed, 5 May 2021 14:41:25 -0500
Subject: [PATCH 12/25] Revert "use np for numpy"

This reverts commit 9e219a04377cbf35191b86f360750184c7cf56c9.
---
 chaco/barplot.py      | 36 ++++++++++++++++++++-------------
 chaco/base_xy_plot.py | 25 +++++++++++------------
 chaco/data_view.py    |  9 +++++----
 chaco/grid_mapper.py  | 13 ++++++------
 chaco/log_mapper.py   | 46 +++++++++++++++++++++++++++----------------
 5 files changed, 74 insertions(+), 55 deletions(-)

diff --git a/chaco/barplot.py b/chaco/barplot.py
index 2299c3eaa..46a30e70e 100644
--- a/chaco/barplot.py
+++ b/chaco/barplot.py
@@ -3,7 +3,15 @@
 import logging
 
 import numpy as np
-
+from numpy import (
+    array,
+    compress,
+    column_stack,
+    invert,
+    isnan,
+    transpose,
+    zeros,
+)
 from traits.api import (
     Any,
     Bool,
@@ -165,14 +173,14 @@ def map_screen(self, data_array):
         # data_array is Nx2 array
         if len(data_array) == 0:
             return np.empty(shape=(0,2))
-        x_ary, y_ary = np.transpose(data_array)
+        x_ary, y_ary = transpose(data_array)
         sx = self.index_mapper.map_screen(x_ary)
         sy = self.value_mapper.map_screen(y_ary)
 
         if self.orientation == "h":
-            return np.transpose(np.array((sx, sy)))
+            return transpose(array((sx, sy)))
         else:
-            return np.transpose(np.array((sy, sx)))
+            return transpose(array((sy, sx)))
 
     def map_data(self, screen_pt):
         """Maps a screen space point into the "index" space of the plot.
@@ -216,7 +224,7 @@ def map_index(
         x = index_data[ndx]
         y = value_data[ndx]
 
-        result = self.map_screen(np.array([[x, y]]))
+        result = self.map_screen(array([[x, y]]))
         if result is None:
             return None
 
@@ -249,7 +257,7 @@ def _gather_points(self):
                 "Chaco: using empty dataset; index_len=%d, value_len=%d."
                 % (len(index), len(value))
             )
-            self._cached_data_pts = np.array([])
+            self._cached_data_pts = array([])
             self._cache_valid = True
             return
 
@@ -262,17 +270,17 @@ def _gather_points(self):
         #              index_range_mask & value_range_mask
 
         index_range_mask = self.index_mapper.range.mask_data(index)
-        nan_mask = np.invert(np.isnan(index_mask))
+        nan_mask = invert(isnan(index_mask))
         point_mask = index_mask & nan_mask & index_range_mask
 
         if self.starting_value is None:
-            starting_values = np.zeros(len(index))
+            starting_values = zeros(len(index))
         else:
             starting_values = self.starting_value.get_data()
 
         if self.bar_width_type == "data":
             half_width = self.bar_width / 2.0
-            points = np.column_stack(
+            points = column_stack(
                 (
                     index - half_width,
                     index + half_width,
@@ -281,8 +289,8 @@ def _gather_points(self):
                 )
             )
         else:
-            points = np.column_stack((index, starting_values, value))
-        self._cached_data_pts = np.compress(point_mask, points, axis=0)
+            points = column_stack((index, starting_values, value))
+        self._cached_data_pts = compress(point_mask, points, axis=0)
 
         self._cache_valid = True
 
@@ -317,7 +325,7 @@ def _draw_plot(self, gc, view_bounds=None, mode="normal"):
                 upper_right_pts[:, 0] += half_width
 
             bounds = upper_right_pts - lower_left_pts
-            gc.rects(np.column_stack((lower_left_pts, bounds)))
+            gc.rects(column_stack((lower_left_pts, bounds)))
             gc.draw_path()
 
     def _draw_default_axes(self, gc):
@@ -333,10 +341,10 @@ def _draw_default_axes(self, gc):
                 if (range.low < 0) and (range.high > 0):
                     if range == self.index_mapper.range:
                         dual = self.value_mapper.range
-                        data_pts = np.array([[0.0, dual.low], [0.0, dual.high]])
+                        data_pts = array([[0.0, dual.low], [0.0, dual.high]])
                     else:
                         dual = self.index_mapper.range
-                        data_pts = np.array([[dual.low, 0.0], [dual.high, 0.0]])
+                        data_pts = array([[dual.low, 0.0], [dual.high, 0.0]])
                     start, end = self.map_screen(data_pts)[0]
                     gc.move_to(int(start[0]) + 0.5, int(start[1]) + 0.5)
                     gc.line_to(int(end[0]) + 0.5, int(end[1]) + 0.5)
diff --git a/chaco/base_xy_plot.py b/chaco/base_xy_plot.py
index b7802c727..f1198dfb6 100644
--- a/chaco/base_xy_plot.py
+++ b/chaco/base_xy_plot.py
@@ -2,6 +2,7 @@
 """
 from math import sqrt
 import numpy as np
+from numpy import around, array, isnan, transpose
 
 # Enthought library imports
 from enable.api import black_color_trait
@@ -351,14 +352,14 @@ def map_screen(self, data_array):
         if len(data_array) == 0:
             return np.empty(shape=(0, 2))
 
-        x_ary, y_ary = np.transpose(data_array)
+        x_ary, y_ary = transpose(data_array)
 
         sx = self.index_mapper.map_screen(x_ary)
         sy = self.value_mapper.map_screen(y_ary)
         if self.orientation == "h":
-            return np.transpose(np.array((sx, sy)))
+            return transpose(array((sx, sy)))
         else:
-            return np.transpose(np.array((sy, sx)))
+            return transpose(array((sy, sx)))
 
     def map_data(self, screen_pt, all_values=False):
         """Maps a screen space point into the "index" space of the plot.
@@ -372,7 +373,7 @@ def map_data(self, screen_pt, all_values=False):
         if self.orientation == "v":
             x, y = y, x
         if all_values:
-            return np.array(
+            return array(
                 (self.index_mapper.map_data(x), self.value_mapper.map_data(y))
             )
         else:
@@ -441,14 +442,14 @@ def map_index(
 
         x = index_data[ndx]
         y = value_data[ndx]
-        if np.isnan(x) or np.isnan(y):
+        if isnan(x) or isnan(y):
             return None
 
         # transform x,y in a 1x2 array, which is the preferred format of
         # map_screen. this makes it robust against differences in
         # the map_screen methods of logmapper and linearmapper
         # when passed a scalar
-        xy = np.array([[x, y]])
+        xy = array([[x, y]])
         sx, sy = self.map_screen(xy).T
         if index_only and (threshold == 0.0 or screen_pt[0] - sx < threshold):
             return ndx
@@ -500,17 +501,13 @@ def _draw_default_axes(self, gc):
                 if (range.low < 0) and (range.high > 0):
                     if range == self.index_mapper.range:
                         dual = self.value_mapper.range
-                        data_pts = np.array(
-                            [[0.0, dual.low], [0.0, dual.high]]
-                        )
+                        data_pts = array([[0.0, dual.low], [0.0, dual.high]])
                     else:
                         dual = self.index_mapper.range
-                        data_pts = np.array(
-                            [[dual.low, 0.0], [dual.high, 0.0]]
-                        )
+                        data_pts = array([[dual.low, 0.0], [dual.high, 0.0]])
                     start, end = self.map_screen(data_pts)
-                    start = np.around(start)
-                    end = np.around(end)
+                    start = around(start)
+                    end = around(end)
                     gc.move_to(int(start[0]), int(start[1]))
                     gc.line_to(int(end[0]), int(end[1]))
                     gc.stroke_path()
diff --git a/chaco/data_view.py b/chaco/data_view.py
index e6b5720ed..3fd4ceaa3 100644
--- a/chaco/data_view.py
+++ b/chaco/data_view.py
@@ -2,6 +2,7 @@
 functions.
 """
 import numpy as np
+from numpy import array, transpose
 
 from traits.api import Bool, Enum, Instance, Property
 from enable.api import color_table
@@ -239,13 +240,13 @@ def map_screen(self, data_array):
 
         if len(data_array) == 0:
             return np.empty(shape=(0,2))
-        x_ary, y_ary = np.transpose(data_array)
+        x_ary, y_ary = transpose(data_array)
         sx = self.index_mapper.map_screen(x_ary)
         sy = self.value_mapper.map_screen(y_ary)
         if self.orientation == "h":
-            return np.transpose(np.array((sx, sy)))
+            return transpose(array((sx, sy)))
         else:
-            return np.transpose(np.array((sy, sx)))
+            return transpose(array((sy, sx)))
 
     def map_data(self, screen_pt):
         """Maps a screen space point into the 2D data space of this plot.
@@ -255,7 +256,7 @@ def map_data(self, screen_pt):
         # At some point it would be good to change the DataView to use
         # the GridMapper, and then use its map_data() method.
         x, y = screen_pt
-        return np.array(
+        return array(
             (self.index_mapper.map_data(x), self.value_mapper.map_data(y))
         )
 
diff --git a/chaco/grid_mapper.py b/chaco/grid_mapper.py
index d192545a1..9d1f5a3bd 100644
--- a/chaco/grid_mapper.py
+++ b/chaco/grid_mapper.py
@@ -8,6 +8,7 @@
 
 # Major library imports
 import numpy as np
+from numpy import column_stack, transpose
 
 # Enthought library imports
 from traits.api import Bool, DelegatesTo, Instance, Float, Property
@@ -118,12 +119,12 @@ def map_screen(self, data_pts):
         """
         # ensure data_array is an Nx2 ndarray
         data_pts = np.asarray(data_pts)
-        data_pts = data_pts.reshape(-1, 2)
-
-        xs, ys = np.transpose(data_pts)
+        data_pts = data_pts.reshape(-1,2)
+    
+        xs, ys = transpose(data_pts)
         screen_xs = self._xmapper.map_screen(xs)
         screen_ys = self._ymapper.map_screen(ys)
-        screen_pts = np.column_stack([screen_xs, screen_ys])
+        screen_pts = column_stack([screen_xs, screen_ys])
         return screen_pts
 
     def map_data(self, screen_pts):
@@ -131,10 +132,10 @@ def map_data(self, screen_pts):
 
         Maps values from screen space into data space.
         """
-        screen_xs, screen_ys = np.transpose(screen_pts)
+        screen_xs, screen_ys = transpose(screen_pts)
         xs = self._xmapper.map_data(screen_xs)
         ys = self._ymapper.map_data(screen_ys)
-        data_pts = np.column_stack([xs, ys])
+        data_pts = column_stack([xs, ys])
         return data_pts
 
     def map_data_array(self, screen_pts):
diff --git a/chaco/log_mapper.py b/chaco/log_mapper.py
index 7aff2408e..4316576dd 100644
--- a/chaco/log_mapper.py
+++ b/chaco/log_mapper.py
@@ -1,6 +1,18 @@
 """ Defines the LogMapper and InvalidDataRangeException classes.
 """
 # Major library imports
+from numpy import (
+    array,
+    isnan,
+    log,
+    log10,
+    exp,
+    zeros,
+    sometrue,
+    floor,
+    ceil,
+    ndarray,
+)
 import numpy as np
 
 # Enthought library imports
@@ -46,8 +58,8 @@ def map_screen(self, data_array):
         Overrides AbstractMapper. Maps values from data space to screen space.
         """
         # Ensure that data_array is actually an array.
-        if not isinstance(data_array, np.ndarray):
-            data_array = np.array(data_array, ndmin=1)
+        if not isinstance(data_array, ndarray):
+            data_array = array(data_array, ndmin=1)
         # First convert to a [0,1] space, then to the screen space.
         if not self._cache_valid:
             self._compute_scale()
@@ -56,15 +68,15 @@ def map_screen(self, data_array):
         else:
             try:
                 with np.errstate(invalid="ignore"):
-                    mask = (data_array <= LOG_MINIMUM) | np.isnan(data_array)
-                if np.sometrue(mask):
-                    data_array = np.array(data_array, copy=True, ndmin=1)
+                    mask = (data_array <= LOG_MINIMUM) | isnan(data_array)
+                if sometrue(mask):
+                    data_array = array(data_array, copy=True, ndmin=1)
                     data_array[mask] = self.fill_value
                 intermediate = (
-                    np.log(data_array) - self._inter_offset
+                    log(data_array) - self._inter_offset
                 ) / self._inter_scale
             except ValueError:
-                intermediate = np.zeros(len(data_array))
+                intermediate = zeros(len(data_array))
 
         result = intermediate * self._screen_scale + self._screen_offset
         return result
@@ -77,10 +89,10 @@ def map_data(self, screen_val):
         if not self._cache_valid:
             self._compute_scale()
         if self._null_screen_range or self._null_data_range:
-            return np.array([self.range.low])
+            return array([self.range.low])
         # First convert to a [0,1] space, then to the data space
         intermediate = (screen_val - self._screen_offset) / self._screen_scale
-        return np.exp(self._inter_scale * intermediate + self._inter_offset)
+        return exp(self._inter_scale * intermediate + self._inter_offset)
 
     def map_data_array(self, screen_vals):
         return self.map_data(screen_vals)
@@ -107,12 +119,12 @@ def _get_safe_scale(self, range):
                 low = 1.0
                 high = 10.0
             else:
-                log_val = np.log10(low)
-                low = pow(10, np.floor(log_val))
-                if np.ceil(log_val) != np.floor(log_val):
-                    high = pow(10, np.ceil(log_val))
+                log_val = log10(low)
+                low = pow(10, floor(log_val))
+                if ceil(log_val) != floor(log_val):
+                    high = pow(10, ceil(log_val))
                 else:
-                    high = pow(10, np.ceil(log_val) + 1)
+                    high = pow(10, ceil(log_val) + 1)
 
         return (low, high)
 
@@ -135,11 +147,11 @@ def _compute_scale(self):
             self._null_data_range = True
         else:
             if low == LOG_MINIMUM:
-                self._inter_scale = np.log(high)
+                self._inter_scale = log(high)
                 self._inter_offset = 0.0
             else:
-                self._inter_scale = np.log(high) - np.log(low)
-                self._inter_offset = np.log(low)
+                self._inter_scale = log(high) - log(low)
+                self._inter_offset = log(low)
             self._screen_scale = screen_range
             self._screen_offset = self.low_pos
 

From fabfc2587048aeeb88d7dcb13f2623bf13c325cc Mon Sep 17 00:00:00 2001
From: Aaron Ayres <aayres@enthought.com>
Date: Wed, 5 May 2021 14:50:07 -0500
Subject: [PATCH 13/25] follow existing lead of using numpy / remove unneeded
 [0]

---
 chaco/barplot.py      | 8 ++++----
 chaco/base_xy_plot.py | 7 +++----
 chaco/data_view.py    | 7 +++----
 chaco/grid_mapper.py  | 5 ++---
 4 files changed, 12 insertions(+), 15 deletions(-)

diff --git a/chaco/barplot.py b/chaco/barplot.py
index 46a30e70e..00e00cb54 100644
--- a/chaco/barplot.py
+++ b/chaco/barplot.py
@@ -2,11 +2,11 @@
 """
 import logging
 
-import numpy as np
 from numpy import (
     array,
     compress,
     column_stack,
+    empty,
     invert,
     isnan,
     transpose,
@@ -168,11 +168,11 @@ def map_screen(self, data_array):
         Implements the AbstractPlotRenderer interface.
         """
         # ensure data_array is an Nx2 ndarray
-        data_array = np.asarray(data_array)
+        data_array = array(data_array)
         data_array = data_array.reshape(-1,2)
         # data_array is Nx2 array
         if len(data_array) == 0:
-            return np.empty(shape=(0,2))
+            return empty(shape=(0,2))
         x_ary, y_ary = transpose(data_array)
         sx = self.index_mapper.map_screen(x_ary)
         sy = self.value_mapper.map_screen(y_ary)
@@ -345,7 +345,7 @@ def _draw_default_axes(self, gc):
                     else:
                         dual = self.index_mapper.range
                         data_pts = array([[dual.low, 0.0], [dual.high, 0.0]])
-                    start, end = self.map_screen(data_pts)[0]
+                    start, end = self.map_screen(data_pts)
                     gc.move_to(int(start[0]) + 0.5, int(start[1]) + 0.5)
                     gc.line_to(int(end[0]) + 0.5, int(end[1]) + 0.5)
                     gc.stroke_path()
diff --git a/chaco/base_xy_plot.py b/chaco/base_xy_plot.py
index f1198dfb6..4627b9a22 100644
--- a/chaco/base_xy_plot.py
+++ b/chaco/base_xy_plot.py
@@ -1,8 +1,7 @@
 """ Defines the base class for XY plots.
 """
 from math import sqrt
-import numpy as np
-from numpy import around, array, isnan, transpose
+from numpy import around, array, empty, isnan, transpose
 
 # Enthought library imports
 from enable.api import black_color_trait
@@ -345,12 +344,12 @@ def map_screen(self, data_array):
         Implements the AbstractPlotRenderer interface.
         """
         # ensure data_array is an Nx2 ndarray
-        data_array = np.asarray(data_array)
+        data_array = array(data_array)
         data_array = data_array.reshape(-1, 2)
 
         # data_array is Nx2 array
         if len(data_array) == 0:
-            return np.empty(shape=(0, 2))
+            return empty(shape=(0, 2))
 
         x_ary, y_ary = transpose(data_array)
 
diff --git a/chaco/data_view.py b/chaco/data_view.py
index 3fd4ceaa3..219af48b6 100644
--- a/chaco/data_view.py
+++ b/chaco/data_view.py
@@ -1,8 +1,7 @@
 """ Defines the DataView class, and associated property traits and property
 functions.
 """
-import numpy as np
-from numpy import array, transpose
+from numpy import array, empty, transpose
 
 from traits.api import Bool, Enum, Instance, Property
 from enable.api import color_table
@@ -235,11 +234,11 @@ def map_screen(self, data_array):
         """
 
         # ensure data_array is an Nx2 ndarray
-        data_array = np.asarray(data_array)
+        data_array = array(data_array)
         data_array = data_array.reshape(-1,2)
 
         if len(data_array) == 0:
-            return np.empty(shape=(0,2))
+            return empty(shape=(0,2))
         x_ary, y_ary = transpose(data_array)
         sx = self.index_mapper.map_screen(x_ary)
         sy = self.value_mapper.map_screen(y_ary)
diff --git a/chaco/grid_mapper.py b/chaco/grid_mapper.py
index 9d1f5a3bd..a88826262 100644
--- a/chaco/grid_mapper.py
+++ b/chaco/grid_mapper.py
@@ -7,8 +7,7 @@
 from contextlib import contextmanager
 
 # Major library imports
-import numpy as np
-from numpy import column_stack, transpose
+from numpy import array, column_stack, transpose
 
 # Enthought library imports
 from traits.api import Bool, DelegatesTo, Instance, Float, Property
@@ -118,7 +117,7 @@ def map_screen(self, data_pts):
         Maps values from data space into screen space.
         """
         # ensure data_array is an Nx2 ndarray
-        data_pts = np.asarray(data_pts)
+        data_pts = array(data_pts)
         data_pts = data_pts.reshape(-1,2)
     
         xs, ys = transpose(data_pts)

From 8639b2d739a4674a86182cff0be8989aa769b6ae Mon Sep 17 00:00:00 2001
From: Aaron Ayres <aayres@enthought.com>
Date: Wed, 5 May 2021 15:51:26 -0500
Subject: [PATCH 14/25] add regression test for enthought/chaco#289

---
 chaco/tools/tests/test_cursor_tool.py | 52 +++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)
 create mode 100644 chaco/tools/tests/test_cursor_tool.py

diff --git a/chaco/tools/tests/test_cursor_tool.py b/chaco/tools/tests/test_cursor_tool.py
new file mode 100644
index 000000000..7a248f115
--- /dev/null
+++ b/chaco/tools/tests/test_cursor_tool.py
@@ -0,0 +1,52 @@
+import unittest
+
+import numpy as np
+
+from enable.api import ComponentEditor
+from enable.testing import EnableTestAssistant
+from traits.api import HasTraits, Instance
+from traits.etsconfig.api import ETSConfig
+from traitsui.api import Item, View
+from traitsui.testing.api import UITester
+
+from chaco.api import ArrayPlotData, Plot
+from chaco.tools.cursor_tool import CursorTool
+
+class TestCursorTool(unittest.TestCase, EnableTestAssistant):
+
+    # regression test for enthought/chaco#289
+    @unittest.skipIf(ETSConfig.toolkit == "null", "Skip on 'null' toolkit")
+    def test_use_with_log_mappers(self):
+        class TestCursor(HasTraits):
+            plot = Instance(Plot)
+
+            traits_view = View(
+                Item('plot', editor=ComponentEditor(), show_label=False),
+                width=500,
+                height=500,
+                resizable=True
+            )
+
+            def _plot_default(self):
+                arr = np.logspace(0, 10, num=10)
+                data = ArrayPlotData(x=arr, y=arr)
+                plot = Plot(data)
+                renderer = plot.plot(
+                    ("x", "y"),
+                    index_scale="log",
+                    value_scale="log"
+                )[0]
+
+                cursor = CursorTool(renderer)
+
+                renderer.overlays.append(cursor)
+            
+                return plot
+
+
+        tester = UITester()
+        test_cursor = TestCursor()
+        with tester.create_ui(test_cursor):
+            self.mouse_move(
+                test_cursor.plot, 10, 10
+            )

From 48e7f9fe0f4887b240628b6ed68929be3fbd0f26 Mon Sep 17 00:00:00 2001
From: Aaron Ayres <aayres@enthought.com>
Date: Wed, 5 May 2021 16:07:01 -0500
Subject: [PATCH 15/25] add comment

---
 chaco/tools/tests/test_cursor_tool.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/chaco/tools/tests/test_cursor_tool.py b/chaco/tools/tests/test_cursor_tool.py
index 7a248f115..3f7ae686e 100644
--- a/chaco/tools/tests/test_cursor_tool.py
+++ b/chaco/tools/tests/test_cursor_tool.py
@@ -47,6 +47,7 @@ def _plot_default(self):
         tester = UITester()
         test_cursor = TestCursor()
         with tester.create_ui(test_cursor):
+            # should not fail
             self.mouse_move(
                 test_cursor.plot, 10, 10
             )

From 77436ac4edf7e14d479db3ea8e4440be11107fea Mon Sep 17 00:00:00 2001
From: Aaron Ayres <aayres@enthought.com>
Date: Thu, 6 May 2021 10:34:37 -0500
Subject: [PATCH 16/25] add regression test for 550

---
 chaco/tools/tests/test_data_label_tool.py | 50 +++++++++++++++++++++++
 1 file changed, 50 insertions(+)
 create mode 100644 chaco/tools/tests/test_data_label_tool.py

diff --git a/chaco/tools/tests/test_data_label_tool.py b/chaco/tools/tests/test_data_label_tool.py
new file mode 100644
index 000000000..50db9f46e
--- /dev/null
+++ b/chaco/tools/tests/test_data_label_tool.py
@@ -0,0 +1,50 @@
+import unittest
+
+import numpy as np
+
+from enable.api import ComponentEditor
+from enable.testing import EnableTestAssistant
+from traits.api import HasTraits, Instance
+from traits.etsconfig.api import ETSConfig
+from traitsui.api import Item, View
+
+from chaco.api import ArrayPlotData, DataLabel, Plot
+from chaco.tools.api import DataLabelTool
+
+IMAGE = np.random.random_integers(0, 255, size=(100, 200)).astype(np.uint8)
+RGB = np.dstack([IMAGE] * 3)
+
+class TestDataLabelTool(unittest.TestCase, EnableTestAssistant):
+
+    # regression test for enthought/chaco#550
+    def test_use_with_2d_plot(self):
+        class Test2DPlot(HasTraits):
+            plot = Instance(Plot)
+
+            traits_view = View(
+                Item('plot', editor=ComponentEditor(), show_label=False),
+                width=500,
+                height=500,
+                resizable=True
+            )
+
+            def _plot_default(self):
+                pd = ArrayPlotData(image=RGB)
+                plot = Plot(pd)
+                self.renderer = plot.img_plot('image')[0]
+
+                label = DataLabel(
+                    component=self.renderer,
+                    data_point=(25,12)
+                )
+                plot.overlays.append(label)
+                tool = DataLabelTool(label)
+                label.tools.append(tool)
+                return plot
+
+        test_2d_plot = Test2DPlot()
+        # should not fail
+        self.press_move_release(
+            test_2d_plot.plot,
+            [(0, 0), (200, 200), (300, 300)],
+        )

From e7fd534f3c94ef963aaa54bf05d44ae965fa863f Mon Sep 17 00:00:00 2001
From: Aaron Ayres <aayres@enthought.com>
Date: Thu, 6 May 2021 10:44:02 -0500
Subject: [PATCH 17/25] flake8

---
 chaco/grid_mapper.py                      | 4 ++--
 chaco/tests/test_plot.py                  | 9 ++++-----
 chaco/tools/tests/test_cursor_tool.py     | 4 ++--
 chaco/tools/tests/test_data_label_tool.py | 4 ++--
 4 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/chaco/grid_mapper.py b/chaco/grid_mapper.py
index a88826262..907a17a2f 100644
--- a/chaco/grid_mapper.py
+++ b/chaco/grid_mapper.py
@@ -118,8 +118,8 @@ def map_screen(self, data_pts):
         """
         # ensure data_array is an Nx2 ndarray
         data_pts = array(data_pts)
-        data_pts = data_pts.reshape(-1,2)
-    
+        data_pts = data_pts.reshape(-1, 2)
+
         xs, ys = transpose(data_pts)
         screen_xs = self._xmapper.map_screen(xs)
         screen_ys = self._ymapper.map_screen(ys)
diff --git a/chaco/tests/test_plot.py b/chaco/tests/test_plot.py
index fe6dd94ff..ff01b9705 100644
--- a/chaco/tests/test_plot.py
+++ b/chaco/tests/test_plot.py
@@ -120,8 +120,7 @@ def test_segment_plot_map_screen(self):
         screen_point = plot_renderer.map_screen([(0, 1), (1, 2)])
 
         self.assertEqual(type(screen_point), np.ndarray)
-        self.assertEqual(screen_point.shape, (1,2,2))
-
+        self.assertEqual(screen_point.shape, (1, 2, 2))
 
     def check_map_screen(self, renderer):
         arr = arange(10)
@@ -130,16 +129,16 @@ def check_map_screen(self, renderer):
         plot_renderer = plot.add_xy_plot(
             'x', 'y', plot.renderer_map[renderer]
         )[0]
-        
+
         screen_point = plot_renderer.map_screen((-1, 1))
 
         self.assertEqual(type(screen_point), np.ndarray)
-        self.assertEqual(screen_point.shape, (1,2))
+        self.assertEqual(screen_point.shape, (1, 2))
 
         screen_point = plot_renderer.map_screen([])
 
         self.assertEqual(type(screen_point), np.ndarray)
-        self.assertEqual(screen_point.shape, (0,2))
+        self.assertEqual(screen_point.shape, (0, 2))
 
     # serves as a regression test for enthought/chaco#272
     def test_xy_plot_map_screen(self):
diff --git a/chaco/tools/tests/test_cursor_tool.py b/chaco/tools/tests/test_cursor_tool.py
index 3f7ae686e..6c27a5b89 100644
--- a/chaco/tools/tests/test_cursor_tool.py
+++ b/chaco/tools/tests/test_cursor_tool.py
@@ -12,6 +12,7 @@
 from chaco.api import ArrayPlotData, Plot
 from chaco.tools.cursor_tool import CursorTool
 
+
 class TestCursorTool(unittest.TestCase, EnableTestAssistant):
 
     # regression test for enthought/chaco#289
@@ -40,9 +41,8 @@ def _plot_default(self):
                 cursor = CursorTool(renderer)
 
                 renderer.overlays.append(cursor)
-            
-                return plot
 
+                return plot
 
         tester = UITester()
         test_cursor = TestCursor()
diff --git a/chaco/tools/tests/test_data_label_tool.py b/chaco/tools/tests/test_data_label_tool.py
index 50db9f46e..fff5a477f 100644
--- a/chaco/tools/tests/test_data_label_tool.py
+++ b/chaco/tools/tests/test_data_label_tool.py
@@ -5,7 +5,6 @@
 from enable.api import ComponentEditor
 from enable.testing import EnableTestAssistant
 from traits.api import HasTraits, Instance
-from traits.etsconfig.api import ETSConfig
 from traitsui.api import Item, View
 
 from chaco.api import ArrayPlotData, DataLabel, Plot
@@ -14,6 +13,7 @@
 IMAGE = np.random.random_integers(0, 255, size=(100, 200)).astype(np.uint8)
 RGB = np.dstack([IMAGE] * 3)
 
+
 class TestDataLabelTool(unittest.TestCase, EnableTestAssistant):
 
     # regression test for enthought/chaco#550
@@ -35,7 +35,7 @@ def _plot_default(self):
 
                 label = DataLabel(
                     component=self.renderer,
-                    data_point=(25,12)
+                    data_point=(25, 12)
                 )
                 plot.overlays.append(label)
                 tool = DataLabelTool(label)

From 0bf267e351888594771cfcf0d1820430e93beb6b Mon Sep 17 00:00:00 2001
From: Aaron Ayres <aayres@enthought.com>
Date: Thu, 6 May 2021 13:06:43 -0500
Subject: [PATCH 18/25] more updates

---
 chaco/polar_line_renderer.py                             | 4 ++--
 chaco/polar_mapper.py                                    | 4 +++-
 examples/demo/advanced/spec_waterfall.py                 | 3 ++-
 examples/demo/basic/hittest_tool.py                      | 4 ++--
 examples/tutorials/scipy2008/custom_overlay_dataspace.py | 2 +-
 examples/tutorials/scipy2008/custom_overlay_movetool.py  | 2 +-
 6 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/chaco/polar_line_renderer.py b/chaco/polar_line_renderer.py
index b34cd5b64..a029d4732 100644
--- a/chaco/polar_line_renderer.py
+++ b/chaco/polar_line_renderer.py
@@ -3,7 +3,7 @@
 
 
 # Major library imports
-from numpy import array, cos, pi, sin, transpose
+from numpy import array, cos, empty, pi, sin, transpose
 
 # Enthought library imports
 from enable.api import black_color_trait, LineStyle
@@ -88,7 +88,7 @@ def map_screen(self, data_array):
         """
 
         if len(data_array) == 0:
-            return []
+            return empty(shape=(0, 2))
         elif len(data_array) == 1:
             xtmp, ytmp = transpose(data_array)
             x_ary = xtmp
diff --git a/chaco/polar_mapper.py b/chaco/polar_mapper.py
index afb0a531c..35311ec3d 100644
--- a/chaco/polar_mapper.py
+++ b/chaco/polar_mapper.py
@@ -4,7 +4,7 @@
 """
 
 # Major library imports
-from numpy import array
+from numpy import array, ndarray
 
 # Enthought library imports
 from traits.api import Bool, Float
@@ -48,6 +48,8 @@ def map_screen(self, data_array):
         if self._null_data_range:
             return array([self.low_pos] * len(data_array))
         else:
+            if not isinstance(data_array, ndarray):
+                data_array = array(data_array, ndmin=1)
             return (data_array - self.range.low) * self._scale + self.low_pos
 
     def map_data(self, screen_val):
diff --git a/examples/demo/advanced/spec_waterfall.py b/examples/demo/advanced/spec_waterfall.py
index 49f45001b..e0a11b35c 100644
--- a/examples/demo/advanced/spec_waterfall.py
+++ b/examples/demo/advanced/spec_waterfall.py
@@ -77,8 +77,9 @@ def map_screen(self, data_array, data_offset=None):
         mapping data_array with y2_mapper.  If data_offset is not
         provided, then y2_mapper is used.
         """
+        print(data_array.shape)
         if len(data_array) == 0:
-            return []
+            return empty(shape=(0,2))
         x_ary, y_ary = transpose(data_array)
         sx = self.index_mapper.map_screen(x_ary)
         if data_offset is not None:
diff --git a/examples/demo/basic/hittest_tool.py b/examples/demo/basic/hittest_tool.py
index 4f45db75c..429552b04 100644
--- a/examples/demo/basic/hittest_tool.py
+++ b/examples/demo/basic/hittest_tool.py
@@ -46,14 +46,14 @@ def normal_mouse_move(self, event):
         else:
             x, y = self.component.map_data((y, x))
 
-        x, y = self.line_plot.map_screen((x, y))
+        x, y = self.line_plot.map_screen((x, y))[0]
         self.pt = self.line_plot.hittest((x, y), threshold=self.threshold)
         self.request_redraw()
 
     def overlay(self, plot, gc, view_bounds=None, mode="normal"):
         # If we have a point, draw it to the screen as a small square
         if self.pt is not None:
-            x, y = plot.map_screen(self.pt)
+            x, y = plot.map_screen(self.pt)[0]
             gc.draw_rect((int(x) - 2, int(y) - 2, 4, 4))
 
 
diff --git a/examples/tutorials/scipy2008/custom_overlay_dataspace.py b/examples/tutorials/scipy2008/custom_overlay_dataspace.py
index 24fb2321d..27b421b69 100644
--- a/examples/tutorials/scipy2008/custom_overlay_dataspace.py
+++ b/examples/tutorials/scipy2008/custom_overlay_dataspace.py
@@ -43,7 +43,7 @@ class CustomOverlay(AbstractOverlay):
 
     def overlay(self, component, gc, view_bounds=None, mode="normal"):
         if self.dataspace:
-            self.x, self.y = component.map_screen(self._anchor)
+            self.x, self.y = component.map_screen(self._anchor)[0]
         gc.set_fill_color(self.color_)
         x = self.x + component.x
         y = self.y + component.y
diff --git a/examples/tutorials/scipy2008/custom_overlay_movetool.py b/examples/tutorials/scipy2008/custom_overlay_movetool.py
index 1b30627f5..b6ad1c305 100644
--- a/examples/tutorials/scipy2008/custom_overlay_movetool.py
+++ b/examples/tutorials/scipy2008/custom_overlay_movetool.py
@@ -53,7 +53,7 @@ class CustomOverlay(AbstractOverlay):
 
     def overlay(self, component, gc, view_bounds=None, mode="normal"):
         if self.dataspace:
-            self.x, self.y = component.map_screen(self._anchor)
+            self.x, self.y = component.map_screen(self._anchor)[0]
         gc.set_fill_color(self.color_)
         x = self.x + component.x
         y = self.y + component.y

From 9e6da2e0f23f748e87eb159b8b2235ab06a49959 Mon Sep 17 00:00:00 2001
From: Aaron Ayres <aayres@enthought.com>
Date: Wed, 12 May 2021 09:02:44 -0500
Subject: [PATCH 19/25] remove debugging print statement

---
 examples/demo/advanced/spec_waterfall.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/examples/demo/advanced/spec_waterfall.py b/examples/demo/advanced/spec_waterfall.py
index e0a11b35c..0df097184 100644
--- a/examples/demo/advanced/spec_waterfall.py
+++ b/examples/demo/advanced/spec_waterfall.py
@@ -77,7 +77,6 @@ def map_screen(self, data_array, data_offset=None):
         mapping data_array with y2_mapper.  If data_offset is not
         provided, then y2_mapper is used.
         """
-        print(data_array.shape)
         if len(data_array) == 0:
             return empty(shape=(0,2))
         x_ary, y_ary = transpose(data_array)

From 2f9a95affd68954b6f3b63b34ce2370b913b1fd1 Mon Sep 17 00:00:00 2001
From: Aaron Ayres <aayres@enthought.com>
Date: Wed, 12 May 2021 09:04:55 -0500
Subject: [PATCH 20/25] clean up map_screen use in LinearMapper hittest method

---
 chaco/lineplot.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/chaco/lineplot.py b/chaco/lineplot.py
index a12c6a2b8..5ac3d3cb5 100644
--- a/chaco/lineplot.py
+++ b/chaco/lineplot.py
@@ -112,10 +112,10 @@ def hittest(self, screen_pt, threshold=7.0, return_distance=False):
             # screen_pt is one of the points in the lineplot
             data_pt = (self.index.get_data()[ndx], self.value.get_data()[ndx])
             if return_distance:
-                scrn_pt = self.map_screen(data_pt)
+                scrn_pt = self.map_screen(data_pt)[0]
                 dist = sqrt(
-                    (screen_pt[0] - scrn_pt[0, 0]) ** 2
-                    + (screen_pt[1] - scrn_pt[0, 1]) ** 2
+                    (screen_pt[0] - scrn_pt[0]) ** 2
+                    + (screen_pt[1] - scrn_pt[1]) ** 2
                 )
                 return (data_pt[0], data_pt[1], dist)
             else:

From a35b264230adcf44967cedfaae12eda7fcdaaeb2 Mon Sep 17 00:00:00 2001
From: Aaron Ayres <aayres@enthought.com>
Date: Wed, 2 Jun 2021 14:30:35 -0500
Subject: [PATCH 21/25] flake8

---
 chaco/plots/segment_plot.py          | 2 +-
 chaco/plots/tests/test_image_plot.py | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/chaco/plots/segment_plot.py b/chaco/plots/segment_plot.py
index 1b8a888e4..13000368f 100644
--- a/chaco/plots/segment_plot.py
+++ b/chaco/plots/segment_plot.py
@@ -152,7 +152,7 @@ def map_screen(self, data_array):
             return np.transpose(np.array((sx, sy)))
         else:
             return np.transpose(np.array((sy, sx)))
-    
+
     def _gather_points(self):
         """Collects the data points that are within the bounds of the plot and
         caches them.
diff --git a/chaco/plots/tests/test_image_plot.py b/chaco/plots/tests/test_image_plot.py
index 6dafc208a..1825f2f69 100644
--- a/chaco/plots/tests/test_image_plot.py
+++ b/chaco/plots/tests/test_image_plot.py
@@ -199,11 +199,11 @@ def test_map_screen(self):
         # itself.
         screen_pt = renderer.map_screen([(0, 0)])
         self.assertEqual(type(screen_pt), np.ndarray)
-        self.assertEqual(screen_pt.shape, (1,2))
+        self.assertEqual(screen_pt.shape, (1, 2))
 
         screen_pt = renderer.map_screen([])
         self.assertEqual(type(screen_pt), np.ndarray)
-        self.assertEqual(screen_pt.shape, (0,2))
+        self.assertEqual(screen_pt.shape, (0, 2))
 
     # regression test for enthought/chaco#528
     @unittest.skipIf(is_null or is_qt4(), "Skip on 'null' or 'qt4' toolkit")

From 58f3a00942334342d0957aa27efc69de6a02accc Mon Sep 17 00:00:00 2001
From: Aaron Ayres <aayres@enthought.com>
Date: Wed, 2 Jun 2021 15:10:27 -0500
Subject: [PATCH 22/25] be less strict in BaseXYPlot

---
 chaco/base_xy_plot.py | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/chaco/base_xy_plot.py b/chaco/base_xy_plot.py
index 4627b9a22..c0ca344cc 100644
--- a/chaco/base_xy_plot.py
+++ b/chaco/base_xy_plot.py
@@ -343,9 +343,13 @@ def map_screen(self, data_array):
 
         Implements the AbstractPlotRenderer interface.
         """
-        # ensure data_array is an Nx2 ndarray
+        # ensure data_array is an N1 x ... Nk x 2 ndarray for some k >= 1
         data_array = array(data_array)
-        data_array = data_array.reshape(-1, 2)
+
+        if data_array.ndim == 1:
+            data_array = data_array.reshape(-1, 2)
+        if data_array.shape[-1] != 2:
+            raise ValueError("Input to map_screen must have shape (..., 2)")
 
         # data_array is Nx2 array
         if len(data_array) == 0:

From 704c75826e20faeae87d45742527565492aafc0c Mon Sep 17 00:00:00 2001
From: aaronayres35 <36972686+aaronayres35@users.noreply.github.com>
Date: Wed, 7 Jul 2021 09:24:28 -0500
Subject: [PATCH 23/25] Remove repeated test_segment_plot_map_screen

---
 chaco/tests/test_plot.py | 12 ------------
 1 file changed, 12 deletions(-)

diff --git a/chaco/tests/test_plot.py b/chaco/tests/test_plot.py
index 7465c1165..9e458d5da 100644
--- a/chaco/tests/test_plot.py
+++ b/chaco/tests/test_plot.py
@@ -122,18 +122,6 @@ def test_text_plot(self):
         actual = gc.bmp_array[:, :, :]
         self.assertFalse(alltrue(actual == 255))
 
-    def test_segment_plot_map_screen(self):
-        x = arange(10)
-        y = arange(1, 11)
-        data = ArrayPlotData(x=x, y=y)
-        plot = Plot(data)
-        plot_renderer = plot.plot(("x", "y"), "segment")[0]
-
-        screen_point = plot_renderer.map_screen([(0, 1), (1, 2)])
-
-        self.assertEqual(type(screen_point), np.ndarray)
-        self.assertEqual(screen_point.shape, (1, 2, 2))
-
     def check_map_screen(self, renderer):
         arr = arange(10)
         data = ArrayPlotData(x=arr, y=arr)

From 32e2ec6c3538cfc11eeec70dbf45a8365d768164 Mon Sep 17 00:00:00 2001
From: aaronayres35 <36972686+aaronayres35@users.noreply.github.com>
Date: Wed, 7 Jul 2021 09:46:37 -0500
Subject: [PATCH 24/25] Remove redundant import

---
 chaco/plots/barplot.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/chaco/plots/barplot.py b/chaco/plots/barplot.py
index eae2e921d..4e8915654 100644
--- a/chaco/plots/barplot.py
+++ b/chaco/plots/barplot.py
@@ -18,7 +18,6 @@
     column_stack,
     empty,
     invert,
-    empty,
     isnan,
     transpose,
     zeros,

From dd3774cc48b62f4a0d1148b543aa691036f3504e Mon Sep 17 00:00:00 2001
From: aaronayres35 <36972686+aaronayres35@users.noreply.github.com>
Date: Wed, 7 Jul 2021 09:47:32 -0500
Subject: [PATCH 25/25] dont remove copyright header

---
 chaco/tools/tests/test_cursor_tool.py | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/chaco/tools/tests/test_cursor_tool.py b/chaco/tools/tests/test_cursor_tool.py
index 25dca3bc2..7f7a443da 100644
--- a/chaco/tools/tests/test_cursor_tool.py
+++ b/chaco/tools/tests/test_cursor_tool.py
@@ -1,3 +1,12 @@
+# (C) Copyright 2005-2021 Enthought, Inc., Austin, TX
+# All rights reserved.
+#
+# This software is provided without warranty under the terms of the BSD
+# license included in LICENSE.txt and may be redistributed only under
+# the conditions described in the aforementioned license. The license
+# is also available online at http://www.enthought.com/licenses/BSD.txt
+#
+# Thanks for using Enthought open source!
 import unittest
 
 import numpy as np