#!/bin/bash
## 2009-07-18:  applying the yHI fixups to a tesseract boxfile, as described in tesseract-training-from-images;
##
## boxfile has one char per line, with coord info, eg:
##	a 830 3513 849 3536 0	<--char "a" in a box with coords x:830..849 y:3513..3536 on page:0  <-- from multi-page tiff
##	a 830 3513 849 3536	<--char "a" in a box with coords x:830..849 y:3513..3536            <-- from simple tiff
##
## USAGE EXAMPLE:  cvt-tesseract-box-fixups  pde.img0005.box.latin1   --revises pde.img0005.box.latin1
##
## Copyright © 2009 Eugene Reimer;  can be used, modified, copied, and distributed or sold under the terms of either the LGPL or the GPL (your choice);
## see http://www.gnu.org/licenses for the details of these terms.

((XHIprv=999999))
((YHIprv=0,YHImax=0,YLOmin=999999))
while read -r CHR XLO YLO XHI YHI PAGENBR;do			##read line of boxfile;  vars get empty-string if omitted (all if empty-line; PAGENBR if simple tiff)
  if [[ $CHR ]] && ((XLO<XHIprv-15));then ((YHIprv=0,YHImax=0,YLOmin=999999));fi	##newline detected;  reset yHImax, yLOmin, etc
  ## [ "$CHR" = "." ];then                             echo "==debug    yHI:$YHI-->$YHIprv($CHRprv) on chr:$CHR at x:$XLO..$XHI" >&2;fi	##debug msg for "."
  if [[ $CHR ]] && ((YHIprv>YHI+4 && YHI-YLO<40));then echo "==revising yHI:$YHI-->$YHIprv($CHRprv) on chr:$CHR at x:$XLO..$XHI" >&2;fi	##debug msg about yHI-revision
  if [[ $CHR ]] && ((YHIprv>YHI+4 && YHI-YLO<40));then ((YHI=YHIprv));fi		##revise yHI using crude heuristic
  if [[ $CHR ]];then echo "$CHR $XLO $YLO $XHI $YHI $PAGENBR"				##write revised-line for boxfile
  else               echo ""								##write empty-line for boxfile
  fi
  if [[ $CHR ]] && ((YHI>YHImax));then ((YHImax=YHI)); CHRmax=$CHR;fi
  if [[ $CHR ]] && ((YLO<YLOmin));then ((YLOmin=YLO)); CHRmin=$CHR;fi
  if [[ $CHR ]];then ((YHIprv=YHI,XHIprv=XHI)); CHRprv=$CHR; fi
done  <$1  >tmp$$-$1						##loop reads $1, writes tmp$$-$1
mv -fv  $1  $1~;  mv -fv  tmp$$-$1  $1  			##rename;  the tmp$$-$1 output replaces $1


exit
CHANGE-LOG:
===========
Consider an even simpler heuristic:  set yHI for all chars in same row to max-in-row -- would mean a 2-pass alg,
	and might well be worse for cases where tesseract has included a spurious speck in a char-blob;
==NOTE: will devise way to cope with such spurious specks, if they become a problem--??--

HEURISTIC:  may yet try using a much fussier test to see whether that helps with lowercase<->uppercase confusion problems;
	but for revisions similar to my manually-made ones on img0005,  need yHI:=yHIprv revisions,  and the comparison needs to be roughly YHI<YHIprv-39 --??--
	NOPE, that won't do;  and anything smaller leads to many other revisions  ==>give up on YHI:YHIprv comparison;
	TRY: fixup-needed if yHI-yLO < 40			<--close and might be ok, but produces un-needed fixups on stroph chars;
	TRY: fixup-needed if yHI-yLO < 40 && yHIprv>yHI+4	<--identical to the ones I made manually  <-- GOING WITH THIS VERSION
	TRY: fixup-needed if yHI-yLOmin < 40 && yHIprv>0	<--got many more un-needed fixups, but why??  due to current yLO being a new min??
	==BETTER:  detect fixup-needed based on HEIGHT==yHI-yLO as a fraction of yHImax-yLOmin--??--

2009-07-22: support empty-lines in boxfile;

NOTE: the problem this script works around may in fact be just another symptom of the "bounding-box at wrong Y-coord" problem==??==