-# The script uses the deprecated dvi->ps->ppm conversion route.
-# If possible, please grab 'dvipng'; it's faster and more robust.
-# If you have it then this script will not be invoked by
-# lyxpreview2bitmap.py.
-# Warning: this legacy support will be removed one day...
+# What does this script do?
+# [legacy_conversion]
+# 0) Process command-line arguments
+# [legacy_conversion_step1]
+# 1) Call latex to create a DVI file from LaTeX
+# [legacy_conversion_step2]
+# 2) Call dvips to create one PS file for each DVI page
+# [legacy_conversion_step3]
+# 3) If dvips fails look for PDF and call gs to produce bitmaps
+# 4) Otherwise call gs on each PostScript file to produce bitmaps
+# [legacy_conversion_pdflatex]
+# 5) Keep track of pages on which gs failed and pass them to pdflatex
+# 6) Call gs on the PDF output from pdflatex to produce bitmaps
+# 7) Extract and write to file (or return to lyxpreview2bitmap)
+# metrics from both methods (standard and pdflatex)
+
+# The script uses the old dvi->ps->png conversion route,
+# which is good when using PSTricks, TikZ or other packages involving
+# PostScript literals (steps 1, 2, 4).
+# This script also generates bitmaps from PDF created by a call to
+# lyxpreview2bitmap.py passing "pdflatex" to the CONVERTER parameter
+# (step 3).
+# Finally, there's also has a fallback method based on pdflatex, which
+# is required in certain cases, if hyperref is active for instance,
+# (step 5, 6).
+# If possible, dvipng should be used, as it's much faster.