From b7cbf7ddf39e87c277ec86afeedd8b1b4b287869 Mon Sep 17 00:00:00 2001
From: Emily Hunt <emily.hunt.physics@gmail.com>
Date: Sat, 18 Jan 2025 23:48:00 +0100
Subject: [PATCH] Tweaks to improve camera stability and allow for zooming out
 at high skating speed

---
 src/sk8plotlib/camera.py | 41 +++++++++++++++++++++++++++++++++++-----
 1 file changed, 36 insertions(+), 5 deletions(-)

diff --git a/src/sk8plotlib/camera.py b/src/sk8plotlib/camera.py
index ff8f5d5..8cfe0e5 100644
--- a/src/sk8plotlib/camera.py
+++ b/src/sk8plotlib/camera.py
@@ -2,18 +2,49 @@ import numpy as np
 
 
 class Camera:
-    def __init__(self, fig, ax, skater):
+    def __init__(
+        self,
+        fig,
+        ax,
+        skater,
+        starting_scale=100,
+        scale=10,
+        scale_response=0.1,
+        zoom_response=0.05,
+    ):
         self.fig, self.ax, self.skater = fig, ax, skater
+        self.scale = starting_scale
+        self.desired_scale = scale
+        self.scale_response = scale_response
+        self.minimum_scale = scale
+        self.zoom_response = zoom_response
 
     def move_camera(self):
-        SCALE = 10
-
         x, y, v_x, v_y = self.skater.x, self.skater.y, self.skater.v_x, self.skater.v_y
         location, velocity = np.asarray([x, y]), np.asarray([v_x, v_y])
 
         location += velocity * 0.05
 
         self.ax.set(
-            xlim=(location[0] - SCALE, location[0] + SCALE),
-            ylim=(location[1] - SCALE, location[1] + SCALE),
+            xlim=(location[0] - self.scale, location[0] + self.scale),
+            ylim=(location[1] - self.scale, location[1] + self.scale),
         )
+        self._update_scale(velocity)
+
+    def _update_scale(self, velocity):
+        excess_velocity = np.linalg.norm(velocity) - 1
+        if excess_velocity > 10:
+            self.desired_scale = np.clip(
+                self.minimum_scale + excess_velocity * self.scale_response,
+                self.minimum_scale,
+                self.minimum_scale * 2.0,
+            )
+        else:
+            self.desired_scale = self.minimum_scale
+
+        scale_change = np.clip(
+            (self.desired_scale - self.scale) * self.zoom_response, -np.inf, self.zoom_response
+        )
+        self.scale += scale_change
+
+        self.skater.set_marker_scale(self.minimum_scale / self.scale)
-- 
2.54.0