cpattern:EndPatch()
If the current patch has less than 4 sides, it is closed with a straight line from the current point to the first point of the patch as if cpattern:LineTo() was used.
Note: If the pattern is not a mesh pattern then it will be put
into an error status with a status of
#CAIRO_STATUS_PATTERN_TYPE_MISMATCH. If the pattern has no current
patch or the current patch already has 4 sides, it will be
put into an error status with a status of
#CAIRO_STATUS_INVALID_MESH_CONSTRUCTION.