class_docstr: For displaying scale-invariant arrows.
  For arrows pointing to a location on a curve, see CurveArrow
class_docstr_tok: ["For","displaying","scale-invariant","arrows",".","For","arrows","pointing","to","a","location","on","a","curve",",","see","CurveArrow"]
code: def dataBounds(self, ax, frac, orthoRange=None):
      pw = 0
      pen = self.pen()
      if not pen.isCosmetic():
          pw = pen.width() * 0.7072
      if self.opts["pxMode"]:
          return [0, 0]
      else:
          br = self.boundingRect()
          if ax == 0:
              return [br.left() - pw, br.right() + pw]
          else:
              return [br.top() - pw, br.bottom() + pw]
  
file_path: pyqtgraph/pyqtgraph/graphicsItems/ArrowItem.py
imports: from math import hypot
  from ..None import functions
  from ..Qt import QtGui, QtWidgets
label_desc: Use image node_id 5 for calling the ArrowItem obj's underlying member method code with example usage: obj.dataBounds(ax, frac, orthoRange) and returns: list, list, list