#!/bin/bash
#
# Copyright (c) 2004 Stephan Müller <smueller@chronox.de>
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions: 
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
#
# Feedback is welcomed :-)
#
# Script allows chaning of the resolution of head 2 based on the configuration
# of X: resolution 0 is leftmost resolution in Monitor definition of X conf
# resolution 1 is second leftmost resolution, and so on
#
# Script allows to clone the second head on the first head using x11vnc that
# copies the second head into a VNC pipe and calling vncviewer.  Script
# automatically scales the size of the displayed vnc window (if second head is
# larger that current head, it shrinks resolution and vice versa). For
# calculating the scaling factor, script checks height of head 1 and height of
# head 2
# 

res=-1 #resolution
clone="no"
scale_factor=""
vhead=0
ihead=1

while getopts "r:s:cCh1" Option
do
	case $Option in
		r)
			# FIXME Check for integer value and then for
			# value between 0 and 9
			if expr "$OPTARG" : "[0-9][0-9]*$" > /dev/null
			then
				res=$OPTARG
			else
				echo "Resolution must be numeric and is the index with zero offset in the X config"
				exit 1
			fi
			;;
		c)
			clone="yes"
			fullscreen=""
			;;
		C)
			clone="yes"
			fullscreen="-fullscreen"
			;;
		1)
			vhead=1
			ihead=0
			;;
		s)
			if expr "$OPTARG" : "[0-9][0-9]*.*[0-9]*$" > /dev/null
			then
				scale_factor=$OPTARG
			else
				echo "The scaling factor must be an unsigned floating point value"
				exit 1
			fi
			;;
		h)
			echo "-r <NUM> Toggles the resolution of the second head to NUM"
			echo "         (resolution 0 is leftmost resolution in Monitor definition of X conf"
			echo "          resolution 1 is second leftmost resolution, and so on)"
			echo "-c Clone head 2 on head 1 using x11vnc and vncviewer with the proper scaling"
			echo "-C Clone using fullscreen window"
			echo "-s <FACTOR> manually scale the display by float FACTOR instead of autoscaling"
			echo "-1 display main head instead of 2nd head (use with -c/-C)"
			;;
	esac
done

# Set resolution of head 2
if [ $res -ge 0 ]
then
	xrandr -d :0.$ihead -s $res
	DISPLAY=:0.0 xrefresh 
	DISPLAY=:0.1 xrefresh 
fi

# Exit if not cloning the screen
if [ "x$clone" != "xyes" ]
then
	exit 0
fi

#Screen "v" height (this is where the viewer is displayed)
h1_y=$(xdpyinfo | grep -A 4 "screen #$vhead" | grep "dimensions" | awk '{print $2}' | awk 'BEGIN {FS="x"} {print $2}')

#Screen "i" height (this one is used as input)
h2_y=$(xdpyinfo | grep -A 4 "screen #$ihead" | grep "dimensions" | awk '{print $2}' | awk 'BEGIN {FS="x"} {print $2}')

# Shrink the Y size a bit to leave room for the window titlebar and kicker
if [ -z "$fullscreen" ]; then
	let h1_y=$h1_y-85
fi

# use autoscaling if no manual scale factor specified
if [ -z "$scale_factor" ]
then
	if [ -z "$fullscreen" ]
	then
		# not fullscreen, don't use scale factors >1.0 to magnify
		SCALE=$(LC_ALL=C awk "BEGIN {s=$h1_y/$h2_y; printf \"%f\n\", (s<1.0 ? s : 1.0)}")
	else
		# fullscreen, always scale to full screen height
		SCALE=$(LC_ALL=C awk "BEGIN {printf \"%f\n\", $h1_y/$h2_y}")
	fi
else
	# manual scale, needs to be in floating point format
	SCALE=$(awk "BEGIN {printf \"%f\n\", $scale_factor}")
fi

export DISPLAY=:0.$vhead
x11vnc -scale "$SCALE" \
       -deferupdate 20 \
       -wait 25 \
       -defer 25 \
       -localhost \
       -cursorpos \
       -display :0.$ihead \
       -bg -q > /dev/null 2>&1 && \
vncviewer -viewonly $fullscreen localhost:0 > /dev/null &