#!/usr/dt/bin/dtksh
#
# xlinedemo - a demo of the X11 capabilities Desktop Korn Shell, dtksh.
#             Written on Solaris.
#
# 01-Apr-2004, ver 0.70
#
# Written for a 24-bit colour display. On non-Solaris, check the path of your
# dtksh (may not be "/usr/dt/bin/dtksh").
#
# USAGE: xlinedemo
#
# See the code for customisation such as window size and colours.
#
# COPYRIGHT: Copyright (c) 2004 Brendan Gregg.
#
#  This program is free software; you can redistribute it and/or
#  modify it under the terms of the GNU General Public License
#  as published by the Free Software Foundation; either version 2
#  of the License, or (at your option) any later version. 
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details. 
#
#  You should have received a copy of the GNU General Public License
#  along with this program; if not, write to the Free Software Foundation, 
#  Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
#
#  (http://www.gnu.org/copyleft/gpl.html)
# 
# 01-Apr-2004	Brendan Gregg	Created this

delay=20			# frame delay (ms)
max_x=500			# window size x
max_y=500			# window size y
colour_fg=MidnightBlue		# line colour
colour_bg=SkyBlue		# background colour


# 
# --- Create X11 window ---
#
XtInitialize TOP linedemo Linedemo $0 
XtCreateManagedWidget FORM form XmForm $TOP \
	resizePolicy:RESIZE_NONE \
	height:$max_y width:$max_x x:0 y:0
XtCreateManagedWidget DRAW draw XmDrawingArea $FORM \
	height:$max_y width:$max_x x:0 y:0 \
	background:$colour_bg foreground:$colour_bg
XtDisplay DISPLAY $FORM
XSync $DISPLAY true
XtRealizeWidget $TOP
XtWindow WINDOW $DRAW

#
# --- Initial line coordinates ---
#
old_x1=10
old_y1=10
old_x2=40
old_y2=10
x1=11
y1=11
x2=41
y2=11
xx1=1
xx2=2
yy1=3
yy2=4


#
# --- Draw line function ---
#
function drawline {
	
	### Calculate new line position

	(( x1 = x1 + xx1 ))
	(( x2 = x2 + xx2 ))
	(( y1 = y1 + yy1 ))
	(( y2 = y2 + yy2 ))
	if (( x1 < 0 || x1 > max_x )); then
		(( x1 = x1 - 2*xx1 ))
		if (( x1 < 10 )); then
			(( xx1 = $RANDOM % 6 + 1 ))
		else
			(( xx1 = - $RANDOM % 6 - 1 ))
		fi
	fi
	if (( x2 < 0 || x2 > max_x )); then
		(( x2 = x2 - 2*xx2 ))
		if (( x2 < 10 )); then
			(( xx2 = $RANDOM % 6 + 1 ))
		else
			(( xx2 = - $RANDOM % 6 - 1 ))
		fi
	fi
	if (( y1 < 0 || y1 > max_y )); then
		(( y1 = y1 - 2*yy1 ))
		if (( y1 < 10 )); then
			(( yy1 = $RANDOM % 6 + 1 ))
		else
			(( yy1 = - $RANDOM % 6 - 1 ))
		fi
	fi
	if (( y2 < 0 || y2 > max_y )); then
		(( y2 = y2 - 2*yy2 ))
		if (( y2 < 10 )); then
			(( yy2 = $RANDOM % 6 + 1 ))
		else
			(( yy2 = - $RANDOM % 6 - 1 ))
		fi
	fi


	### White out old line

#	XDrawLine $DISPLAY $WINDOW \
#		-foreground $colour_bg \
#		-line_width 1 \
#		-line_style LineSolid \
#		$old_x1 $old_y1 $old_x2 $old_y2


	### Draw new line

	XDrawLine $DISPLAY $WINDOW \
		-foreground $colour_fg \
		-line_width 1 \
		-line_style LineSolid \
		$x1 $y1 $x2 $y2


	### Save old position

	old_x1=$x1
	old_y1=$y1
	old_x2=$x2
	old_y2=$y2

	XtAddTimeOut ID $delay drawline		# pause, then draw next
}


#
# --- Main ---
#
XtAddTimeOut ID $delay drawline			# pause, then draw line
XtMainLoop