def _getDisplayDensity(self, strip=True):
        """
        Get display density

        Args:
            strip: strip the output

        Returns:
            display density

        """
        BASE_DPI = 160.0
        d = self.getprop('ro.sf.lcd_density', strip)
        if d:
            return float(d) / BASE_DPI
        d = self.getprop('qemu.sf.lcd_density', strip)
        if d:
            return float(d) / BASE_DPI
        return -1.0

        Get display density

        Args:
            strip: strip the output

        Returns:
            display density

        
airtest/core/android/adb.py