Merge pull request matplotlib#20544 from Tortar/patch-2

Support of different locations for the text fixing cursor of TextBox

Author: jklymak

doc/users/next_whats_new/positioning_of_text_inside_TextBox.rst

@@ -0,0 +1,13 @@
+Text can be positioned inside TextBox widget
+--------------------------------------------
+
+A new parameter called *textalignment* can be used to control for the position of the text inside the Axes of the TextBox widget.
+
+.. plot::
+
+  from matplotlib import pyplot as plt
+  from matplotlib.widgets import TextBox
+
+  box_input = plt.axes([0.2, 0.2, 0.1, 0.075])
+  text_box = TextBox(ax=box_input, initial="text", label="", textalignment="center")
+

examples/widgets/textbox.py

@@ -40,7 +40,7 @@ def submit(expression):
 
 
 axbox = fig.add_axes([0.1, 0.05, 0.8, 0.075])
-text_box = TextBox(axbox, "Evaluate")
+text_box = TextBox(axbox, "Evaluate", textalignment="center")
 text_box.on_submit(submit)
 text_box.set_val("t ** 2")  # Trigger `submit` with the initial string.
 

lib/matplotlib/tests/test_widgets.py

@@ -369,10 +369,14 @@ def test_TextBox():
     submit_event = Mock()
     text_change_event = Mock()
     ax = get_ax()
-
-    tool = widgets.TextBox(ax, 'Evaluate')
+    tool = widgets.TextBox(ax, '')
     tool.on_submit(submit_event)
     tool.on_text_change(text_change_event)
+
+    assert tool.text == ''
+
+    do_event(tool, '_click')
+
     tool.set_val('x**2')
 
     assert tool.text == 'x**2'
@@ -382,6 +386,7 @@ def test_TextBox():
     tool.stop_typing()
 
     assert submit_event.call_count == 2
+
     do_event(tool, '_click')
     do_event(tool, '_keypress', key='+')
     do_event(tool, '_keypress', key='5')

lib/matplotlib/widgets.py

@@ -1119,9 +1119,11 @@ class TextBox(AxesWidget):
         lambda self: self._observers.callbacks['change']))
     submit_observers = _api.deprecated("3.4")(property(
         lambda self: self._observers.callbacks['submit']))
+    DIST_FROM_LEFT = _api.deprecate_privatize_attribute("3.5")
 
     def __init__(self, ax, label, initial='',
-                 color='.95', hovercolor='1', label_pad=.01):
+                 color='.95', hovercolor='1', label_pad=.01,
+                 textalignment="left"):
         """
         Parameters
         ----------
@@ -1137,20 +1139,26 @@ def __init__(self, ax, label, initial='',
             The color of the box when the mouse is over it.
         label_pad : float
             The distance between the label and the right side of the textbox.
+        textalignment : {'left', 'center', 'right'}
+            The horizontal location of the text.
         """
         super().__init__(ax)
 
-        self.DIST_FROM_LEFT = .05
+        self._DIST_FROM_LEFT = .05
+
+        self._text_position = _api.check_getitem(
+            {"left": 0.05, "center": 0.5, "right": 0.95},
+            textalignment=textalignment)
 
         self.label = ax.text(
             -label_pad, 0.5, label, transform=ax.transAxes,
             verticalalignment='center', horizontalalignment='right')
 
         # TextBox's text object should not parse mathtext at all.
         self.text_disp = self.ax.text(
-            self.DIST_FROM_LEFT, 0.5, initial,
-            transform=self.ax.transAxes, verticalalignment='center',
-            horizontalalignment='left', parse_math=False)
+            self._text_position, 0.5, initial, transform=self.ax.transAxes,
+            verticalalignment='center', horizontalalignment=textalignment,
+            parse_math=False)
 
         self._observers = cbook.CallbackRegistry()
 
@@ -1193,12 +1201,22 @@ def _rendercursor(self):
 
         text = self.text_disp.get_text()  # Save value before overwriting it.
         widthtext = text[:self.cursor_index]
+
+        bb_text = self.text_disp.get_window_extent()
         self.text_disp.set_text(widthtext or ",")
-        bb = self.text_disp.get_window_extent()
-        if not widthtext:  # Use the comma for the height, but keep width to 0.
-            bb.x1 = bb.x0
+        bb_widthtext = self.text_disp.get_window_extent()
+
+        if bb_text.y0 == bb_text.y1:  # Restoring the height if no text.
+            bb_text.y0 -= (bb_widthtext.y1-bb_widthtext.y0)/2
+            bb_text.y1 += (bb_widthtext.y1-bb_widthtext.y0)/2
+        elif not widthtext:  # Keep width to 0.
+            bb_text.x1 = bb_text.x0
+        else:  # Move the cursor using width of bb_widthtext.
+            bb_text.x1 = bb_text.x0 + (bb_widthtext.x1 - bb_widthtext.x0)
+
         self.cursor.set(
-            segments=[[(bb.x1, bb.y0), (bb.x1, bb.y1)]], visible=True)
+            segments=[[(bb_text.x1, bb_text.y0), (bb_text.x1, bb_text.y1)]],
+            visible=True)
         self.text_disp.set_text(text)
 
         self.ax.figure.canvas.draw()