public Integer getDPI() throws GuacamoleException {
        return getIntegerParameter(DPI_PARAMETER);
    }
Returns the display resolution desired for the Guacamole session over
the tunnel being requested, in DPI.

@return
    The display resolution desired for the Guacamole session over the
    tunnel being requested, or null if no resolution was given.

@throws GuacamoleException
    If the resolution specified was not a valid integer.
guacamole/src/main/java/org/apache/guacamole/tunnel/TunnelRequest.java