class_docstr: **Bases:** :class:`GLGraphicsItem <pyqtgraph.opengl.GLGraphicsItem.GLGraphicsItem>`
  
  Displays three lines indicating origin and orientation of local coordinate system. 
code: def paint(self):
      # glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)
      # glEnable( GL_BLEND )
      # glEnable( GL_ALPHA_TEST )
      self.setupGLState()
  
      if self.antialias:
          glEnable(GL_LINE_SMOOTH)
          glHint(GL_LINE_SMOOTH_HINT, GL_NICEST)
  
      glBegin(GL_LINES)
  
      x, y, z = self.size()
      glColor4f(0, 1, 0, 0.6)  # z is green
      glVertex3f(0, 0, 0)
      glVertex3f(0, 0, z)
  
      glColor4f(1, 1, 0, 0.6)  # y is yellow
      glVertex3f(0, 0, 0)
      glVertex3f(0, y, 0)
  
      glColor4f(0, 0, 1, 0.6)  # x is blue
      glVertex3f(0, 0, 0)
      glVertex3f(x, 0, 0)
      glEnd()
  
file_path: pyqtgraph/pyqtgraph/opengl/items/GLAxisItem.py
imports: from OpenGL.GL import *
  from ...None import QtGui
  from ..GLGraphicsItem import GLGraphicsItem
label_desc: Use image node_id 4 for calling the GLAxisItem obj's underlying member method code with example usage: obj.paint() without return types