Updated the position_cursor function of Textbox

Tortar · Tortar · commit 971d59e393e9 · 2022-10-08T20:37:39.000+02:00
create char_index_at inside text class

Update widgets.py

Update widgets.py

Update text.py

solved bug in caching

Simpler logic

Co-authored-by: Tim Hoffmann &lt;2836374+timhoffm@users.noreply.github.com&gt;

make char_index_at private as suggested

Co-authored-by: Tim Hoffmann &lt;2836374+timhoffm@users.noreply.github.com&gt;

refer to private method

change __str__ to str

mistake in applying a change fixed
diff --git a/lib/matplotlib/text.py b/lib/matplotlib/text.py
@@ -279,6 +279,41 @@ def _get_multialignment(self):
         else:
             return self._horizontalalignment
 
+    def _char_index_at(self, x):
+        """
+        Calculates the index nearer to x, we accumulate
+        the width of each character contained in the text
+        and find the index at which the distance between the
+        click position and the accumulated sum is minimal.
+        This works only on single line texts.
+        """
+
+        if (not hasattr(self, "_saved_fontproperties") or
+                str(self._fontproperties) != self._saved_fontproperties):
+
+            self._saved_fontproperties = str(self._fontproperties)
+            self._chars_size = dict()  # to cache results
+
+        text = self._text
+
+        if len(text) == 0:
+            return 0
+
+        else:
+            for char in set(text):
+                if char not in self._chars_size:
+                    self.set_text(char)
+                    bb = self.get_window_extent()
+                    self._chars_size[char] = bb.x1 - bb.x0
+
+            self.set_text(text)
+            bb = self.get_window_extent()
+
+            size_accum = np.cumsum([0] + [self._chars_size[x] for x in text])
+
+            std_x = x - bb.x0
+            return (np.abs(size_accum - std_x)).argmin()
+
     def get_rotation(self):
         """Return the text angle in degrees between 0 and 360."""
         if self.get_transform_rotates_text():
diff --git a/lib/matplotlib/widgets.py b/lib/matplotlib/widgets.py
@@ -1315,17 +1315,6 @@ def stop_typing(self):
             # call it once we've already done our cleanup.
             self._observers.process('submit', self.text)
 
-    def position_cursor(self, x):
-        # now, we have to figure out where the cursor goes.
-        # approximate it based on assuming all characters the same length
-        if len(self.text) == 0:
-            self.cursor_index = 0
-        else:
-            bb = self.text_disp.get_window_extent()
-            ratio = np.clip((x - bb.x0) / bb.width, 0, 1)
-            self.cursor_index = int(len(self.text) * ratio)
-        self._rendercursor()
-
     def _click(self, event):
         if self.ignore(event):
             return
@@ -1338,7 +1327,8 @@ def _click(self, event):
             event.canvas.grab_mouse(self.ax)
         if not self.capturekeystrokes:
             self.begin_typing(event.x)
-        self.position_cursor(event.x)
+        self.cursor_index = self.text_disp._char_index_at(event.x)
+        self._rendercursor()
 
     def _resize(self, event):
         self.stop_typing()
