This small macro turns the arrow of the mouse in a precision cross. Small example of using the class ViewObserver() and the use of the keyboard with SoKeyboardEvent

Macro Mouse Cross.FCMacro

# -*- coding: utf-8 -*-
# mouse cursor to Cross or Arrow + Grig 
# ver 0.2 08/08/2014  PyQt4 and PySide
# ver 0.4 07/06/2019 compatible Python 3.
#
__title__   = "Macro_Mouse_Cross"
__author__  = "Mario52"
__wiki__    = "https://www.freecadweb.org/wiki/Macro_Mouse_Cross"
__url__     = "http://www.freecadweb.org/index-fr.html"
__version__ = "00.04"
__date__    = "07/06/2019"

try:
    from PyQt4 import QtCore, QtGui
except Exception:
    from PySide import QtCore, QtGui
from pivy import coin

global xx ;xx = -1

#################### create document if not exist #######################
doc = FreeCAD.ActiveDocument                                         ####
if doc == None:                                                      ####
    doc = FreeCAD.newDocument()                                      ####
#########################################################################
class ViewObserver:
   def logPosition(self, info):
       global xx
       self.pos = info["Key"]
       if (self.pos.upper() == "Q"):
           v.removeEventCallback("SoKeyboardEvent",c)
           FreeCAD.Console.PrintMessage("End Macro_Mouse_Cross"+"\n")
       if (self.pos.upper() == "C"):
           # change the cursor cross ( + )
           QtGui.QApplication.setOverrideCursor(QtGui.QCursor(QtCore.Qt.CrossCursor))
       elif (self.pos.upper() == "A"):
           # change the cursor in Arrow
           QtGui.QApplication.setOverrideCursor(QtGui.QCursor(QtCore.Qt.ArrowCursor))
       elif (self.pos.upper() == "X") and (info["State"] == "DOWN"):
           # change the cursor and visualise all model 
           xx += 1
           if xx == 0:
               QtGui.QApplication.setOverrideCursor(QtGui.QCursor(QtCore.Qt.ArrowCursor))
               FreeCAD.Console.PrintMessage("ArrowCursor"+"\n")
           if xx == 1:
               QtGui.QApplication.setOverrideCursor(QtGui.QCursor(QtCore.Qt.UpArrowCursor))
               FreeCAD.Console.PrintMessage("UpArrowCursor"+"\n")
           if xx == 2:
               QtGui.QApplication.setOverrideCursor(QtGui.QCursor(QtCore.Qt.CrossCursor))
               FreeCAD.Console.PrintMessage("CrossCursor"+"\n")
           if xx == 3:
               QtGui.QApplication.setOverrideCursor(QtGui.QCursor(QtCore.Qt.WaitCursor))
               FreeCAD.Console.PrintMessage("WaitCursor"+"\n")
           if xx == 4:
               QtGui.QApplication.setOverrideCursor(QtGui.QCursor(QtCore.Qt.IBeamCursor))
               FreeCAD.Console.PrintMessage("IBeamCursor"+"\n")
           if xx == 5:
               QtGui.QApplication.setOverrideCursor(QtGui.QCursor(QtCore.Qt.SizeVerCursor))
               FreeCAD.Console.PrintMessage("SizeVerCursor"+"\n")
           if xx == 6:
               QtGui.QApplication.setOverrideCursor(QtGui.QCursor(QtCore.Qt.SizeHorCursor))
               FreeCAD.Console.PrintMessage("SizeHorCursor"+"\n")
           if xx == 7:
               QtGui.QApplication.setOverrideCursor(QtGui.QCursor(QtCore.Qt.SizeBDiagCursor))
               FreeCAD.Console.PrintMessage("SizeBDiagCursor"+"\n")
           if xx == 8:
               QtGui.QApplication.setOverrideCursor(QtGui.QCursor(QtCore.Qt.SizeFDiagCursor))
               FreeCAD.Console.PrintMessage("SizeFDiagCursor"+"\n")
           if xx == 9:
               QtGui.QApplication.setOverrideCursor(QtGui.QCursor(QtCore.Qt.SizeAllCursor))
               FreeCAD.Console.PrintMessage("SizeAllCursor"+"\n")
           if xx == 10:
               QtGui.QApplication.setOverrideCursor(QtGui.QCursor(QtCore.Qt.BlankCursor))
               FreeCAD.Console.PrintMessage("BlankCursor"+"\n")
           if xx == 11:
               QtGui.QApplication.setOverrideCursor(QtGui.QCursor(QtCore.Qt.SplitVCursor))
               FreeCAD.Console.PrintMessage("SplitVCursor"+"\n")
           if xx == 12:
               QtGui.QApplication.setOverrideCursor(QtGui.QCursor(QtCore.Qt.SplitHCursor))
               FreeCAD.Console.PrintMessage("SplitHCursor"+"\n")
           if xx == 13:
               QtGui.QApplication.setOverrideCursor(QtGui.QCursor(QtCore.Qt.PointingHandCursor))
               FreeCAD.Console.PrintMessage("PointingHandCursor"+"\n")
           if xx == 14:
               QtGui.QApplication.setOverrideCursor(QtGui.QCursor(QtCore.Qt.ForbiddenCursor))
               FreeCAD.Console.PrintMessage("ForbiddenCursor"+"\n")
           if xx == 15:
               QtGui.QApplication.setOverrideCursor(QtGui.QCursor(QtCore.Qt.OpenHandCursor))
               FreeCAD.Console.PrintMessage("OpenHandCursor"+"\n")
           if xx == 16:
               QtGui.QApplication.setOverrideCursor(QtGui.QCursor(QtCore.Qt.ClosedHandCursor))
               FreeCAD.Console.PrintMessage("ClosedHandCursor"+"\n")
           if xx == 17:
               QtGui.QApplication.setOverrideCursor(QtGui.QCursor(QtCore.Qt.WhatsThisCursor))
               FreeCAD.Console.PrintMessage("WhatsThisCursor"+"\n")
           if xx == 18:
               QtGui.QApplication.setOverrideCursor(QtGui.QCursor(QtCore.Qt.BusyCursor))
               FreeCAD.Console.PrintMessage("BusyCursor"+"\n")
           if xx == 19:
               QtGui.QApplication.setOverrideCursor(QtGui.QCursor(QtCore.Qt.BitmapCursor))
               FreeCAD.Console.PrintMessage("BitmapCursor"+"\n")
               xx = -1
       elif (self.pos.upper() == "G"):
           # "wmayer" http://forum.freecadweb.org/viewtopic.php?f=3&t=1065&hilit=cross#p8818
           # Create Grida
           grid=coin.SoType.fromName("SoDrawingGrid").createInstance()
           Gui.ActiveDocument.ActiveView.getSceneGraph().addChild(grid)
xx = -1 

try:
    v=Gui.activeDocument().activeView()
    o = ViewObserver()
    c = v.addEventCallback("SoKeyboardEvent",o.logPosition)
    App.Console.PrintMessage("Type Key C to Cross"+"\n")
    App.Console.PrintMessage("Type Key A to Arrow"+"\n")
    App.Console.PrintMessage("Type Key X to Visualise all cursor"+"\n")
    App.Console.PrintMessage("Type Key G to Grid (not editable)"+"\n")
    App.Console.PrintMessage("Type Key Q to Quit"+"\n")
except Exception:
    FreeCAD.Console.PrintError("\n"+"Not document open"+"\n")