#! /bin/sh
# Make a small-caps version of an AFM file
# usage: mk-sc scale afm-file-name >new-afm-file-name
# 
# scale is the ratio between the small and the large caps (e.g, 0.8)
#
# bugs: doesn't set these fields properly:
#	FontBBox
#	KPX data for lowercase is discarded
#
# rounding is done with int(x+0.5) --- this is wrong for -ve values

trap "rm -f /tmp/afm$$0[012] /tmp/kern$$" 0

csplit -f /tmp/afm$$ -s $2 /StartKernPairs/+1 /EndKernPairs/ 

# chardata now in /tmp/afm$$00, kern in /tmp/afm$$01, 
# composites in /tmp/afm$$02

# first do the kern data

awk 'BEGIN {	
	lower= "abcdefghijklmnopqrstuvwxyz";
	upper= "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    }

    /^$/ { next; }

    /^KPX/ && $2 ~ /^[A-Z]$/ && $3 ~ /^[A-Z]$/ {
	# insert extra kerning data for lower case, based on upper case
	lwr2=substr(lower, index(upper, $2), 1);
	lwr3=substr(lower, index(upper, $3), 1);
	print "KPX", lwr2, $3, $4
	print "KPX", $2, lwr3, $4
	print "KPX", lwr2, lwr3, $4
	print $0
	next;
    }

    /^KPX/ && ($2 ~ /^[a-z]$/ || $3 ~ /^[a-z]$/) {
	# filter out kerning applied to lower-case
		next;
    }
    { print ; }' /tmp/afm$$01 |
sort +1 -3 |
awk '
    $2 != last { printf "\n" ; last= $2 }
    { print }
' >/tmp/kern$$ 

# now process the chardata, and put the bits together
awk 'BEGIN {'scale=$1';}

    /^FontName/ {
	print $0 "-SmallCaps";
	next;
	}

    /^FullName/ {
	print $0, "SmallCaps";
	next;
	}

    /^CapHeight/ {
	print "XHeight", int($2*scale + 0.5)
	}

    /^XHeight/ { next;}

    /^Descender/ {
	print "Descender 0";
	next;
	}

    /^C / {
	ch = $2;
	if (ch >= 65 && ch <= 90) {
		# it is an upper case letter, so save the (scaled) metric info
		ch += 32;
		w[ch] = int($5 * scale + 0.5);
		llx[ch] = int($11 * scale + 0.5);
		lly[ch] = int($12 * scale + 0.5);
		urx[ch] = int($13 * scale + 0.5);
		ury[ch] = int($14 * scale + 0.5);
		print;
	} else if (ch >= 97 && ch <= 122) {
		# it is a lower case letter -- substitute the saved info
		printf "C %d ; WX %d ; N %s ; B %d %d %d %d\n", \
		  ch, w[ch], $8, llx[ch], lly[ch], urx[ch], ury[ch], ";";
		# do not want any ligature info
	} else
	  	print;

	next;
   }

   {print}' /tmp/afm$$00 |
cat - /tmp/kern$$ /tmp/afm$$02