# Example 11 -- Fancy plot

.thin. = 0.5			# for whole data set
.thick. = 2			# for bravo time period
.gray_for_guiding_lines. = 0.75	# for guiding lines
.tmin. = 1964			# time axis
.tmax. = 1974
.tinc. = 5
.tincinc. = 1
.missing_value. = -9
\file = "./example11.dat"
#
# Guiding lines to draw on both panels.
#
.1xl. = 1962
.1yb. = -3
.1xr. = 1968
.1yt. = 3
.1slope. = {rpn .1yt. .1yb. - .1xr. .1xl. - /}
.1intercept. = {rpn .1yb. .1slope. .1xl. * -}
.2xl. = 1966.4
.2yb. = 3
.2xr. = 1980
.2yt. = -1
.2slope. = {rpn .2yt. .2yb. - .2xr. .2xl. - /}
.2intercept. = {rpn .2yb. .2slope. .2xl. * -}
#
# PANEL 1: Bravo time period.
#
set x margin 3
set x size 15
set y margin 3
set y size 5
# Draw border big enough for this and next panel.
draw border box {rpn ..xmargin.. 2 -} {rpn ..ymargin.. 2 -} {rpn ..xmargin.. ..xsize.. + 2 +} {rpn ..ymargin.. ..ysize.. 2 * 3 + + 2 +} 0.2 0.75
set missing value .missing_value.
set ignore error eof
set x name "Year"
set x axis .tmin. .tmax. .tinc. .tincinc.
set y name "Area / 10$^5$km$^2$"
set y axis -3 3 1
draw axes
#
# Draw index lines 1 and 2.
# 
# Upward sloped line.
set line width .thin.
set graylevel .gray_for_guiding_lines.
if {rpn .1intercept. ..xright.. .1slope. * + ..ytop.. <}
    draw line from              \
	..xleft..               \
	{rpn .1intercept. ..xleft.. .1slope. * +} \
	to                      \
	{rpn ..ytop.. .1intercept. - .1slope. /} \
	..ytop..
else
    draw line from              \
	..xleft..               \
	{rpn .1intercept. ..xleft.. .1slope. * +} \
	to                      \
	..xright..              \
	{rpn .1intercept. ..xright.. .1slope. * +}
end if
set graylevel 0
# 
# Downward sloped line.
set line width .thin.
set graylevel .gray_for_guiding_lines.
if {rpn .2intercept. ..xleft.. .2slope. * + ..ytop.. <}
    draw line from              \
	{rpn ..ytop.. .2intercept. - .2slope. /} \
	..ytop..                \
	to                      \
	..xright..              \
	{rpn .2intercept. ..xright.. .2slope. * +}  
else
    draw line from              \
	..xleft..               \
	{rpn .2intercept. ..xleft.. .2slope. * +} \
	to                      \
	..xright..              \
	{rpn .2intercept. ..xright.. .2slope. * +}
end if
set graylevel 0
#
# Finally, draw the data curve on top, after first
# whiting out a background.
set input data window x .tmin. .tmax.
open \file
read columns x y
close
y /= 1e5
set line width ..linewidthaxis..
draw zero line
set line width {rpn .thick. 3 *}
set graylevel 1
draw curve
set graylevel 0
set line width .thick.
draw curve

#
# PANEL 2: Longer timescale.
#
delete x scale
set x margin bigger 5
set x size 10
set x name ""
set y name ""
set y margin bigger {rpn ..ysize.. 3 +}
#
# Draw long data set in thin pen.
set input data window x off
open \file
read columns x y
close
y /= 1e5
#
# Draw guiding lines, axes, etc.
set x axis 1952 1980 5 1
draw axes frame
set line width .thin.
set graylevel .gray_for_guiding_lines.
draw line from .1xl. .1yb. to .1xr. .1yt.
draw line from .2xl. .2yb. to .2xr. .2yt.
set graylevel 0
set line width ..linewidthaxis..
draw zero line


draw x axis at bottom
.old. = ..fontsize..
set font size 0
draw y axis at left
set font size .old.
delete .old.
#
# Draw full curve (first whiting out region around it).
set line width {rpn .thin. 4 *}
set graylevel 1
draw curve
set graylevel 0
set line width .thin.
draw curve
#
# Draw bravo time period (first whiting out region around it).
set input data window x .tmin. .tmax.
open \file
read columns x y
close
y /= 1e5
set line width {rpn .thick. 3 *}
set graylevel 1
draw curve
set graylevel 0
set line width .thick.
draw curve
#
# Done
set font size 20
\label = "Example 11 (Arctic ice anomaly)"
draw label "\label" at          \
    {rpn 8.5 2.54 * "\label" width - 2 /} \
    {rpn ..ytop.. yusertocm 0.7 +} \
    cm
if !..publication..
    draw time stamp
end if
