Don't draw lines and point with zero elements (#2737)

Author: einarf

CHANGELOG.md

@@ -10,6 +10,8 @@ Arcade [PyPi Release History](https://pypi.org/project/arcade/#history) page.
   atlas is resized or rebuilt. This way it's easy to track when texture coordinates
   has changed.
 - Added `Text.visible` (bool) property to control the visibility of text objects.
+- Fixed an issue causing points and lines to draw random primitives when
+  passing in an empty list.
 
 ## 3.3.0
 

arcade/draw/line.py

@@ -112,6 +112,8 @@ def draw_lines(point_list: Point2List, color: RGBOrA255, line_width: float = 1)
 
     line_pos_array = array.array("f", (v for point in point_list for v in point))
     num_points = len(point_list)
+    if num_points == 0:
+        return
 
     # Grow buffer until large enough to hold all our data
     goal_buffer_size = num_points * 3 * 4

arcade/draw/point.py

@@ -64,6 +64,8 @@ def draw_points(point_list: Point2List, color: RGBOrA255, size: float = 1.0) ->
 
     # Get # of points and translate Python tuples to a C-style array
     num_points = len(point_list)
+    if num_points == 0:
+        return
     point_array = array.array("f", (v for point in point_list for v in point))
 
     # Resize buffer