`Line`/`SmoothLine` - `ellipse`: Handle the number of segments to match `Ellipse` (#8187)

kivy/graphics/vertex_instructions_line.pxi

@@ -927,7 +927,10 @@ cdef class Line(VertexInstruction):
         * (optional) angle_start and angle_end are in degree. The default
           value is 0 and 360.
         * (optional) segments is the precision of the ellipse. The default
-          value is calculated from the range between angle.
+          value is calculated from the range between angle. You can use this
+          property to create polygons with 3 or more sides. Values smaller than
+          3 will not be represented and the number of segments will be
+          automatically calculated.
 
         Note that it's up to you to :attr:`close` or not.
         If you choose to close, use :attr:`close_mode` to define how the figure
@@ -950,6 +953,8 @@ cdef class Line(VertexInstruction):
         .. versionchanged:: 2.2.0
             Now you can get the ellipse generated through the property.
 
+            The minimum number of segments allowed is 3. Smaller values will be
+            ignored and the number of segments will be automatically calculated.
         '''
 
         def __get__(self):
@@ -988,7 +993,9 @@ cdef class Line(VertexInstruction):
         if 0 in (w, h):
             return
 
-        if segments <= 0:
+        if segments < 3:
+            if segments != 0:
+                Logger.warning(f'{self.__class__.__name__} - ellipse: A minimum of 3 segments is required. The default value will be used instead.')
             segments = int(abs(angle_end - angle_start) / 2) + extra_segments
 
         segments += extra_segments
@@ -998,7 +1005,7 @@ cdef class Line(VertexInstruction):
             angle_dir = 1
         else:
             angle_dir = -1
-        
+
         # Resulting ellipse
         self._ellipse = (x, y, w, h, angle_start, angle_end, segments)
         # Reset other properties