major performance improvement when building a songbook

make songbook.pdf :
 - before patch: 5mn23s
 - after patch: 14s

The issue was about LaTeX \graphicspath macro that was used for
covers.  Since covers are stored in each artist's directory,
\graohicspath was containing a large number of different paths which
resulted in quite some time to evaluate when using \includegraphics.

This small patch copies all covers in a single temporary directory
before building a songbook. Note that symlinks are quite tricky to use
with pdflatex, esp. with MacOs/Windows plateforms so a hard copy has
been preferred.

songbook.py

@@ -9,13 +9,32 @@ import re
 import json
 import locale
 import sortindex
+import shutil
+
+def copyCovers():
+   '''
+   Copy all covers found in songs/ hierarchy into a same folder.  This
+   allows a much faster search for pdflatex since the \graphicspath
+   macro now only contains a single directory instead of quite a long
+   list to search through.
+   '''
+   #create "covers/" directory if it does not exist
+   d = os.path.dirname("covers/")
+   if not os.path.exists(d):
+      os.makedirs(d)
+
+   covers = list(set(glob.glob('songs/*/*.jpg')))
+   for cover in covers:
+      f = "covers/" + os.path.basename(cover)
+      if(os.path.exists(f) == False):
+         shutil.copy(cover, f)
 
 def matchRegexp(reg, iterable):
     return [ m.group(1) for m in (reg.match(l) for l in iterable) if m ]
 
 def songslist(songs):
     directories = set(["img/"] + map(lambda x: "songs/" + os.path.dirname(x), songs))
-    result = ['\\graphicspath{'] + [ '  {{{0}/}},'.format(d) for d in directories ] + ['}'] + [ '\\input{{songs/{0}}}'.format(s.strip()) for s in songs ]
+    result = [ '\\input{{songs/{0}}}'.format(s.strip()) for s in songs ]
     return '\n'.join(result)
 
 def parseTemplate(template):
@@ -187,6 +206,8 @@ def main():
         sb = json.load(f)
         f.close()
 
+        copyCovers()
+
         if depend:
             makeDepend(sb, output)
         else:

templates/ancient.tmpl

@@ -67,9 +67,7 @@
 \newindex{titleidx}{\getname_title}
 \newauthorindex{authidx}{\getname_auth}
 
-\graphicspath{
+\graphicspath{ {covers/}, {img/} }
-  {img/},
-}
 
 \definecolor{SongNumberBgColor}{HTML}{\getsongnumberbgcolor}
 \definecolor{NoteBgColor}{HTML}{\getnotebgcolor}

templates/minimal.tmpl

@@ -44,7 +44,7 @@
 \newindex{titleidx}{\getname_title}
 \newauthorindex{authidx}{\getname_auth}
 
-\graphicspath{ {img/} }
+\graphicspath{ {covers/}, {img/} }
 
 %hide song number
 \renewcommand{\printsongnum}[1]{}

templates/patacrep-en.tmpl

@@ -67,9 +67,7 @@
 \newindex{titleidx}{\getname_title}
 \newauthorindex{authidx}{\getname_auth}
 
-\graphicspath{
+\graphicspath{ {covers/}, {img/} }
-  {img/},
-}
 
 \definecolor{SongNumberBgColor}{HTML}{\getsongnumberbgcolor}
 \definecolor{NoteBgColor}{HTML}{\getnotebgcolor}

templates/patacrep.tmpl

@@ -67,9 +67,7 @@
 \newindex{titleidx}{\getname_title}
 \newauthorindex{authidx}{\getname_auth}
 
-\graphicspath{
+\graphicspath{ {covers/}, {img/} }
-  {img/},
-}
 
 \definecolor{SongNumberBgColor}{HTML}{\getsongnumberbgcolor}
 \definecolor{NoteBgColor}{HTML}{\getnotebgcolor}