#=======================================================================
# A complex example of a CDAT x-y line plot.
#
# Copyright (c) 2003 by Johnny Lin.  For licensing, distribution
# conditions, contact information, and additional documentation see
# the URL http://www.johnny-lin.com/pylib.html#license.
#=======================================================================


#- Import modules:

import Numeric as N
import vcs


#- Data:  A sine curve:

x = N.arange(17)*N.pi/8.
y = N.sin(x)


#- Open VCS canvas:

v = vcs.init()


#- Create x vs. y graphics method object and template:

my_gm = v.createxvsy('my_graph_meth', 'default')
my_tpl = v.createtemplate('my_template', 'default')


#- Set plot symbol to square and linestyle to dashed:

my_gm.marker = 11
my_gm.line = 1


#- Set coordinates (normalized units) for lower-left and upper-
#  right bounding box (bbll*, bbur*); set height of font for 
#  the overall title (title_fontht), [xy]titles (xytitle_fontht),
#  and for the tick labels (ticklabel_fontht); set length of tick 
#  marks (in normalized units):

bbllx = 0.25
bblly = 0.25
bburx = 0.75
bbury = 0.75
title_fontht = 40
xytitle_fontht = 30
ticklabel_fontht = 30
ticklength = 0.01


#- Set font to use for the ticklabels (ticklabel_font) and the
#  titles (titles_font):

ticklabel_font = 2
titles_font = 2


#- Set conversion factor to multiply font height coordinates by
#  to obtain the value in normalized coordinates.  This is set
#  by trial-and-error:

fontht2norm = 0.0007


#- Create text-table and text-orientation objects for x- and 
#  y-axis tick labels and using them set font and font height.
#  Also set y-axis tick labels to be vertically aligned at the
#  mid-way point:

ttab_xticklabel = v.createtexttable('xticklabel_ttab', 'default')
ttab_yticklabel = v.createtexttable('yticklabel_ttab', 'default')
tori_xticklabel = v.createtextorientation('xticklabel_tori', 'defcenter')
tori_yticklabel = v.createtextorientation('yticklabel_tori', 'default')

ttab_xticklabel.font = ticklabel_font
ttab_yticklabel.font = ticklabel_font
tori_xticklabel.height = ticklabel_fontht
tori_yticklabel.height = ticklabel_fontht
tori_yticklabel.valign = 'half'


#- Create text-combined objects for overall title and axis 
#  titles and set font, height, and content:

text_title = v.createtext( 'title_ttab', 'default' \
                         , 'title_tori', 'defcenter' )
text_title.font = titles_font
text_title.height = title_fontht
text_title.string = 'A Nice Sine Curve'

text_xtitle = v.createtext( 'xtitle_ttab', 'default' \
                          , 'xtitle_tori', 'defcenter' )
text_xtitle.font = titles_font
text_xtitle.height = xytitle_fontht
text_xtitle.string = 'x'

text_ytitle = v.createtext( 'ytitle_ttab', 'default' \
                          , 'ytitle_tori', 'defcentup' )
text_ytitle.font = titles_font
text_ytitle.height = xytitle_fontht
text_ytitle.string = 'sin(x)'


#- Turn off some default titling fields:

my_tpl.xname.priority = 0
my_tpl.yname.priority = 0
my_tpl.mean.priority = 0
my_tpl.max.priority = 0
my_tpl.min.priority = 0


#- Set position of data field, plot box, and x-axis bottom ticks 
#  and labels; set text-table and text-orientation of x-axis bottom 
#  labels; turn off upper-right set of tick labels:

my_tpl.data.x1 = my_tpl.box1.x1 = bbllx
my_tpl.data.y1 = my_tpl.box1.y1 = bblly
my_tpl.data.x2 = my_tpl.box1.x2 = bburx
my_tpl.data.y2 = my_tpl.box1.y2 = bbury

my_tpl.xtic1.y1 = bblly - ticklength
my_tpl.xtic1.y2 = bblly
my_tpl.xlabel1.y = bblly - (3.0 * ticklength)
my_tpl.xlabel1.texttable = ttab_xticklabel
my_tpl.xlabel1.textorientation = tori_xticklabel

my_tpl.xtic2.priority = 0
my_tpl.ytic2.priority = 0


#- Calculate "nice" x-axis labels and set them into the graphics
#  method, with no more than 8 ticks on the axis:

my_gm.xticlabels1 = vcs.mklabels( vcs.mkscale(min(x), max(x), 8) )


#- Calculate "nice" y-axis labels, set them in the graphics method,
#  calculate y-axis title location based on the longest label 
#  length, set y-axis ticks and tick label locations, and set
#  text-table and text-orientation for y-axis tick labels:

ylabels = vcs.mklabels( vcs.mkscale(min(y), max(y)) )
my_gm.yticlabels1 = ylabels
longest_ylabels = \
    max([ len(ylabels.values()[i]) for i in range(len(ylabels))] )

my_tpl.ytic1.x1 = bbllx - ticklength
my_tpl.ytic1.x2 = bbllx
my_tpl.ylabel1.x = bbllx - ticklength \
                 - ( longest_ylabels * ticklabel_fontht * fontht2norm )
my_tpl.ylabel1.texttable = ttab_yticklabel
my_tpl.ylabel1.textorientation = tori_yticklabel


#- Position overall title, x-axis title, and y-axis title:

text_title.x = [ (bburx-bbllx)/2.0 + bbllx ]
text_title.y = [ bbury + (1.7 * title_fontht * fontht2norm) ]

text_xtitle.x = [ (bburx-bbllx)/2.0 + bbllx ]
text_xtitle.y = [ my_tpl.xlabel1.y - (1.7 * title_fontht * fontht2norm) ]

text_ytitle.x = [ my_tpl.ylabel1.x - ( 1.6 * title_fontht * fontht2norm ) ]
text_ytitle.y = [ (bbury-bblly)/2.0 + bblly ]


#- Render plot, plot overall title, x-axis title, and y-axis title:

v.plot(x, y, my_gm, my_tpl, name=' ')
v.plot(text_title)
v.plot(text_xtitle)
v.plot(text_ytitle)


#- Postscript output of the plot:

v.postscript('sine_plot.ps')
v.gif('sine_plot.gif')




#====== end of file ======