# Demonstration
# Creating a sequence of 100 BMP files to show the variation of potential
#   along an axis of an electrostatic solution
# File names set to generate an AVI animation with CECIL_B
# Stanley Humphries, Field Precision, Copyright 2010
import subprocess

# ---------------------
# Set control parameters
# Range and step size along z axis
ZMin = -0.065
ZMax = 0.065
NStep = 100
dZ = (ZMax-ZMin)/NStep
# Graphics file resolution
XRes = "640"
YRes = "480"
# File names
# Saved surface plot view to set style, orientation and view limits. The
#   variable parameter (SurfacePlanePos) has been replaced with @
ViewTemplate = "template.fpv"
# Temporary view file with different values of SurfacePlanePos
ViewTemp = "temp.fpv"
ViewTempPrefix = "temp"
# Script file to call phiview, referencing the current view file
Script = "pvscript.scr"
ScriptPrefix = "pvscript"
ProgName = "phiview"

# ---------------------
# Loop along the z axis
for n in range(NStep+1):
    Z = ZMin + n*dZ
# Create the temporary view file, replacing @ with the current position Z
    InView = open(ViewTemplate,'r')
    OutView = open(ViewTemp,'w')
    while 1:
        line = InView.readline()
        if not line: break
        line = line.replace("@",str(Z))
        OutView.write(line)

    InView.close()
    OutView.close()
# Create the BMP file prefix
    if n < 10:
      BMPFilePrefix = "bmpout" + "00" + str(n)
    elif n < 100:
      BMPFilePrefix = "bmpout" + "0" + str(n)
    else:
      BMPFilePrefix = "bmpout" + str(n)
    print BMPFilePrefix
# Write the PhiView script
    OutScript = open(Script,'w')
    OutScript.write("INPUT TARGET.HOU\n")
    PlotCommand = "PLOT " + ViewTempPrefix + " " + BMPFilePrefix + " " + XRes + " " + YRes
    OutScript.write (PlotCommand + '\n')
    OutScript.write ('ENDFILE\n')
    OutScript.close()
# Run phiview to generate the BMP file
    Command = ProgName + " " + ScriptPrefix 
    subprocess.Popen(Command).wait()

# ---------------------