Jose' Matos wrote:
>> I'm trying to write 'lyxpreview2png.py', to be used by lyx to
>> generate previews using dvipng. What versions of python do we
>> support? (Should I go use 'atoi' or do it the 'int' way?)
>
> We support 1.5.2, so to be on the compatible side 'atoi' is the
> way to go.
Thanks, Jose.
I have an 'almost finished' python script, attached. Would you mind
casting a look over it and telling me how to improve it?
One thing I don't know how to do:
# Ascertain whether the latex and dvipng
# executables are available.
latex = "latex"
dvipng = "dvipng"
I'd like to write a little function to loop over a list of 'possible'
names (lib/configure checks for pplatex latex2e latex) and return the
first one found in the path. Any ideas on how to do that?
--
Angus#! /usr/bin/env python
# file lyxpreview2png.py
# This file is part of LyX, the document processor.
# Licence details can be found in the file COPYING.
#
# author Angus Leeming
# with much advice from David Kastrup, [EMAIL PROTECTED]
#
# Full author contact details are available in file CREDITS
# This script takes a LaTeX file and generates a collection of
# png image files, one per previewed snippet.
# Pre-requisites:
# * A latex executable.
# * preview.sty
# * dvipng
# preview.sty and dvipng are part of the preview-latex project
# (http://preview-latex.sourceforge.net/).
# preview.sty can alternatively be obtained from
# CTAN/macros/latex/contrib/supported/preview.
# This script takes four arguments:
# TEXFILE: the name of the .tex file to be converted.
# DPI: a scale factor, passed to dvipng.
# FG_COLOR the foreground color as a hexadecimal string, eg '000000'.
# BG_COLOR the background color as a hexadecimal string, eg 'faf0e6'.
# If successful, this script will leave in dir ${DIR}:
# a (possibly large) number of image files with names like
# ${BASE}\([0-9]*\).png
# a file containing info needed by LyX to position the images correctly
# on the screen.
# ${BASE}.metrics
import os, re, sys
from string import atoi
hexcolor_re = re.compile("^[0-9a-fA-F]{6}$")
latex_file_re = re.compile("\.tex$")
preview_re = re.compile("^Preview: [ST]")
def usage(prog_name):
print "Usage: %s <latex file> <dpi> <fg color> <bg color>" % (prog_name)
print "\twhere the colors are hexadecimal strings, eg 'faf0e6'"
def make_texcolor(hexcolor):
# Test that the input string contains 6 hexadecimal chars
if not hexcolor_re.match(hexcolor):
print "Cannot convert '%s'" %(hexcolor)
sys.exit(1)
red = float(atoi(hexcolor[0:2], 16)) / 255.0
green = float(atoi(hexcolor[2:4], 16)) / 255.0
blue = float(atoi(hexcolor[4:6], 16)) / 255.0
return "rgb %f %f %f" % (red, green, blue)
def run_command(prog_name, prog_call):
pid = os.fork()
if pid == 0:
os.execvp(prog_name, prog_call)
print "%s failed", prog_name
os.exit(1)
pid, exit_status = os.waitpid(pid, 0)
return exit_status == 0
def extract_metrics_info(log_file, metrics_file):
success = 0
metrics = open(metrics_file, 'w')
for line in open(log_file, 'r').readlines():
if preview_re.match(line) > 0:
success = 1
metrics.write(line)
return success
def main(argv):
# Parse and manipulate the command line arguments
if len(argv) != 5:
usage(argv[0])
sys.exit(1)
latex_file = argv[1]
dpi = int(argv[2])
fg_color = make_texcolor(argv[3])
bg_color = make_texcolor(argv[4])
# Ascertain whether the latex and dvipng executables are available.
latex = "latex"
dvipng = "dvipng"
# Compile the latex file.
latex_call = [latex, latex_file]
if not run_command(latex, latex_call):
print "%s failed to compile %s" % (latex, latex_file)
sys.exit(1)
# Run the dvi file through dvipng.
dvi_file = latex_file_re.sub(".dvi", latex_file)
dvipng_call = [dvipng, "-T", "tight", "-depth", "-D", "%d" % dpi, \
"-fg", fg_color, "-bg", bg_color, dvi_file]
if not run_command(dvipng, dvipng_call):
print "%s failed to generate images from %s" % (dvipng, dvi_file)
sys.exit(1)
# Extract metrics info from the latex log file.
log_file = latex_file_re.sub(".log", latex_file)
metrics_file = latex_file_re.sub(".metrics", latex_file)
if not extract_metrics_info(log_file, metrics_file):
print "Failed to extract metrics info from %s" %(metrics_file)
sys.exit(1)
if __name__ == "__main__":
main(sys.argv)
