code: def heightChanged(self):
      sr = self.getSourceRect()
      ar = float(sr.width()) / sr.height()
      self.params.param("width").setValue(
          int(self.params["height"] * ar), blockSignal=self.widthChanged
      )
  
file_path: pyqtgraph/pyqtgraph/exporters/ImageExporter.py
imports: import sys
  import numpy
  from ..None import functions
  from ..parametertree import Parameter
  from ..Qt import QtCore, QtGui, QtWidgets
  from .Exporter import Exporter
label_desc: Use image node_id 3 for calling the ImageExporter obj's underlying member method code with example usage: obj.heightChanged() without return types