ANEW -legend_demo

NEEDS -gnuplot

DOC
(*
	#!/usr/bin/env python
	# Thanks to Charles Twardy for this example
	#
	#See http://matplotlib.sf.net/examples/legend_demo2.py for an example
	#controlling which lines the legend uses and the order

	import numpy as np
	import matplotlib.pyplot as plt

	a = np.arange(0,3,.02)
	b = np.arange(0,3,.02)
	c = np.exp(a)
	d = c[::-1]

	ax = plt.subplot(111)
	plt.plot(a,c,'k--',a,d,'k:',a,c+d,'k')
	plt.legend(('Model length', 'Data length', 'Total message length'),
		   'upper center', shadow=True, fancybox=True)
	plt.ylim([-1,20])
	plt.grid(False)
	plt.xlabel('Model complexity --->')
	plt.ylabel('Message length --->')
	plt.title('Minimum Message Length')

	plt.setp(plt.gca(), 'yticklabels', [])
	plt.setp(plt.gca(), 'xticklabels', [])

	# set some legend properties.  All the code below is optional.  The
	# defaults are usually sensible but if you need more control, this
	# shows you how
	leg = plt.gca().get_legend()
	ltext  = leg.get_texts()  # all the text.Text instance in the legend
	llines = leg.get_lines()  # all the lines.Line2D instance in the legend
	frame  = leg.get_frame()  # the patch.Rectangle instance surrounding the legend

	# see text.Text, lines.Line2D, and patches.Rectangle for more info on
	# the settable properties of lines, text, and rectangles
	frame.set_facecolor('0.80')      # set the frame face color to light gray
	plt.setp(ltext, fontsize='small')    # the legend text fontsize
	plt.setp(llines, linewidth=1.5)      # the legend linewidth
	#leg.draw_frame(False)           # don't draw the legend frame
	plt.show()
*)
ENDDOC

: func1 ( F: x -- r ) FEXP ;
: func2 ( F: x -- r ) 3e FSWAP F- FEXP ;
: func3 ( F: x -- r ) FDUP func1 FSWAP func2 F+ ;

: legend_demo ( -- )
	0 FIGURE CLF  FALSE GRID
	S" Minimum Message length" TITLE
	S" Model complexity %\rightarrow%" XLABEL
	S" Message length %\rightarrow%"   YLABEL
	MLEGEND-POS >S 5 TO MLEGEND-POS
	S" Model length"  S" Data length"  S" Total message length" 3 LEGEND
	S" unset xtics; unset ytics" TWEAK$
	[PHOLD
	  0e 3e S" red--" ['] func1 #300 FPLOT 
	  0e 3e S" blue:" ['] func2 #300 FPLOT 
	  0e 3e S" black" ['] func3 #300 FPLOT 
	PHOLD] 
	S> TO MLEGEND-POS ;