def METHOD_NAME(self, width):
    self.ui.doubleSpinBox_width_inches.blockSignals(True)
    new_width_inches = width / float(self.ui.spinBox_dpi.value())
    self.ui.doubleSpinBox_width_inches.setValue(new_width_inches)
    self.ui.doubleSpinBox_width_inches.blockSignals(False)