From 4ce123be44dd7570d1562fa03dcd690b24b14d60 Mon Sep 17 00:00:00 2001
From: Grant Sanderson <grant@3blue1brown.com>
Date: Thu, 26 Aug 2021 11:44:45 -0700
Subject: [PATCH] (Maybe temporary?) upates to Tracers

---
 manimlib/mobject/changing.py | 29 +++++++++++++++++------------
 1 file changed, 17 insertions(+), 12 deletions(-)

diff --git a/manimlib/mobject/changing.py b/manimlib/mobject/changing.py
index c8339fcd..febe4acb 100644
--- a/manimlib/mobject/changing.py
+++ b/manimlib/mobject/changing.py
@@ -8,7 +8,6 @@ from manimlib.mobject.mobject import Mobject
 from manimlib.mobject.types.vectorized_mobject import VMobject
 from manimlib.mobject.types.vectorized_mobject import VGroup
 from manimlib.utils.rate_functions import smooth
-from manimlib.utils.space_ops import get_norm
 
 
 class AnimatedBoundary(VGroup):
@@ -82,7 +81,7 @@ class TracedPath(VMobject):
         "stroke_color": WHITE,
         "time_traced": np.inf,
         "fill_opacity": 0,
-        "time_per_anchor": 0.1,
+        "time_per_anchor": 1 / 15,
     }
 
     def __init__(self, traced_point_func, **kwargs):
@@ -99,22 +98,28 @@ class TracedPath(VMobject):
         self.traced_points.append(point)
 
         if self.time_traced < np.inf:
-            n_relevant_points = int(self.time_traced / dt)
-            n_anchors = int(self.time_traced / self.time_per_anchor)
+            n_relevant_points = int(self.time_traced / dt + 0.5)
+            # n_anchors = int(self.time_traced / self.time_per_anchor)
             n_tps = len(self.traced_points)
-            points = [
-                self.traced_points[max(n_tps - int(alpha * n_relevant_points) - 1, 0)]
-                for alpha in np.linspace(1, 0, n_anchors)
-            ]
+            if n_tps < n_relevant_points:
+                points = self.traced_points + [point] * (n_relevant_points - n_tps)
+            else:
+                points = self.traced_points[n_tps - n_relevant_points:]
+            # points = [
+            #     self.traced_points[max(n_tps - int(alpha * n_relevant_points) - 1, 0)]
+            #     for alpha in np.linspace(1, 0, n_anchors)
+            # ]
             # Every now and then refresh the list
             if n_tps > 10 * n_relevant_points:
                 self.traced_points = self.traced_points[-n_relevant_points:]
         else:
-            sparseness = max(int(self.time_per_anchor / dt), 1)
-            points = self.traced_points[::sparseness]
-            points[-1] = self.traced_points[-1]
+            # sparseness = max(int(self.time_per_anchor / dt), 1)
+            # points = self.traced_points[::sparseness]
+            # points[-1] = self.traced_points[-1]
+            points = self.traced_points
 
-        self.set_points_smoothly(points)
+        if points:
+            self.set_points_smoothly(points)
 
         self.time += dt
         return self