Clarify error message when the atlas is full (#2555)

* Clarify error message when the atlas is full

* Unnecessary f-string

* Fix annotation issues in the draw module

* Import sorting

Author: einarf

arcade/draw/line.py

@@ -1,7 +1,7 @@
 import array
 
 from arcade import gl
-from arcade.types import Color, Point2List, RGBOrA255
+from arcade.types import Color, Point2, Point2List, RGBOrA255
 from arcade.window_commands import get_window
 
 from .helpers import _generic_draw_line_strip, get_points_for_thick_line
@@ -23,8 +23,8 @@ def draw_line_strip(point_list: Point2List, color: RGBOrA255, line_width: float
     if line_width == 1:
         _generic_draw_line_strip(point_list, color, gl.LINE_STRIP)
     else:
-        triangle_point_list: Point2List = []
-        # This needs a lot of improvement
+        triangle_point_list: list[Point2] = []
+        # FIXME: This needs a lot of improvement
         last_point = None
         for point in point_list:
             if last_point is not None:

arcade/draw/polygon.py

@@ -1,6 +1,6 @@
 from arcade import gl
 from arcade.earclip import earclip
-from arcade.types import Point2List, RGBOrA255
+from arcade.types import Point2, Point2List, RGBOrA255
 
 from .helpers import _generic_draw_line_strip, get_points_for_thick_line
 
@@ -40,7 +40,7 @@ def draw_polygon_outline(point_list: Point2List, color: RGBOrA255, line_width: f
     new_point_list.append(point_list[0])
 
     # Create a place to store the triangles we'll use to thicken the line
-    triangle_point_list = []
+    triangle_point_list: list[Point2] = []
 
     # This needs a lot of improvement
     last_point = None

arcade/texture_atlas/uv_data.py

@@ -124,7 +124,11 @@ def get_existing_or_free_slot(self, name: str) -> int:
             return slot
         except IndexError:
             raise Exception(
-                ("No more free slots in the UV texture. " f"Max number of slots: {self._num_slots}")
+                (
+                    "No more free slots in the UV texture."
+                    f"Max number of textures: {self._num_slots}."
+                    "Consider creating a texture atlas with a larger capacity."
+                )
             )
 
     def free_slot_by_name(self, name: str) -> None: