Merge pull request matplotlib#12459 from anntzer/imshow-cursordata

Improve formatting of imshow() cursor data when a colorbar exists.

Author: efiring

doc/users/next_whats_new/2018-10-10-AL.rst

@@ -0,0 +1,9 @@
+Improved formatting of image values under cursor when a colorbar is present
+```````````````````````````````````````````````````````````````````````````
+
+When a colorbar is present, its formatter is now used to format the image
+values under the mouse cursor in the status bar.  For example, for an image
+displaying the values 10,000 and 10,001, the statusbar will now (using default
+settings) display the values as ``0.0+1e4`` and ``1.0+1e4`` (or ``10000.0``
+and ``10001.0`` if the offset-text is disabled on the colorbar), whereas both
+values were previously displayed as ``1e+04``.

lib/matplotlib/artist.py

@@ -2,6 +2,7 @@
 from functools import wraps
 import inspect
 import logging
+from numbers import Number
 import re
 import warnings
 
@@ -1165,8 +1166,8 @@ def format_cursor_data(self, data):
             data[0]
         except (TypeError, IndexError):
             data = [data]
-        data_str = ', '.join('{:0.3g}'.format(item) for item in data if
-                   isinstance(item, (np.floating, np.integer, int, float)))
+        data_str = ', '.join('{:0.3g}'.format(item) for item in data
+                             if isinstance(item, Number))
         return "[" + data_str + "]"
 
     @property

lib/matplotlib/cbook/__init__.py

@@ -302,11 +302,25 @@ def local_over_kwdict(local_var, kwargs, *keys):
 
 
 def strip_math(s):
-    """remove latex formatting from mathtext"""
-    remove = (r'\mathdefault', r'\rm', r'\cal', r'\tt', r'\it', '\\', '{', '}')
-    s = s[1:-1]
-    for r in remove:
-        s = s.replace(r, '')
+    """
+    Remove latex formatting from mathtext.
+
+    Only handles fully math and fully non-math strings.
+    """
+    if len(s) >= 2 and s[0] == s[-1] == "$":
+        s = s[1:-1]
+        for tex, plain in [
+                (r"\times", "x"),  # Specifically for Formatter support.
+                (r"\mathdefault", ""),
+                (r"\rm", ""),
+                (r"\cal", ""),
+                (r"\tt", ""),
+                (r"\it", ""),
+                ("\\", ""),
+                ("{", ""),
+                ("}", ""),
+        ]:
+            s = s.replace(tex, plain)
     return s
 
 

lib/matplotlib/image.py

@@ -906,6 +906,15 @@ def get_cursor_data(self, event):
         else:
             return arr[i, j]
 
+    def format_cursor_data(self, data):
+        if self.colorbar:
+            return ("["
+                    + cbook.strip_math(self.colorbar.formatter(data))
+                    + cbook.strip_math(self.colorbar.formatter.get_offset())
+                    + "]")
+        else:
+            return super().format_cursor_data(data)
+
 
 class NonUniformImage(AxesImage):
     def __init__(self, ax, *, interpolation='nearest', **kwargs):

lib/matplotlib/tests/test_image.py

@@ -262,6 +262,24 @@ def test_cursor_data():
     assert im.get_cursor_data(event) is None
 
 
+def test_format_cursor_data():
+    from matplotlib.backend_bases import MouseEvent
+
+    fig, ax = plt.subplots()
+    im = ax.imshow([[10000, 10001]])
+
+    xdisp, ydisp = ax.transData.transform_point([0, 0])
+    event = MouseEvent('motion_notify_event', fig.canvas, xdisp, ydisp)
+    assert im.get_cursor_data(event) == 10000
+    assert im.format_cursor_data(im.get_cursor_data(event)) == "[1e+04]"
+
+    fig.colorbar(im)
+    fig.canvas.draw()  # This is necessary to set up the colorbar formatter.
+
+    assert im.get_cursor_data(event) == 10000
+    assert im.format_cursor_data(im.get_cursor_data(event)) == "[0.0+1e4]"
+
+
 @image_comparison(baseline_images=['image_clip'], style='mpl20')
 def test_image_clip():
     d = [[1, 2], [3, 4]]