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2021-01-23 21:18:01 -05:00
parent 371789994e
commit 806480d924
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trace2scad Executable file
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#!/bin/bash
# trace2scad
# 2015 by Hank Dietz, http://aggregate.org/hankd/
# This script is distributed as full source subject
# to the Creative Commons - Attribution constraints.
# You use it at your own risk, with no warranty, etc.
version=20150415
complex=4096
filter=2
gamma=1
pixerr=1.0
xres=2000
yres=2000
level=0.48
levels=$level
negate=""
turd=5
subres=5
align=0
verbose=""
prefix="no_prefix_set"
ppm='/tmp/trace2scad'$$'.ppm'
pgm='/tmp/trace2scad'$$'.pgm'
svg='/tmp/trace2scad'$$'.svg'
raw='/tmp/trace2scad'$$'.raw'
stmp='/tmp/trace2scad'$$'.scad'
scad=""
myname="$0"
if [[ $# < 1 ]]
then
echo "Error: type $myname -h for usage" 1>&2
exit 1
fi
while [[ $# > 0 ]]
do
key="$1"
shift
case $key in
-a|--align)
align=1
;;
-c|--complex)
complex="$1"
shift
;;
-e|--pixerr)
pixerr="$1"
shift
;;
-f|--filter)
filter="$1"
shift
;;
-g|--gamma)
gamma="$1"
shift
;;
-x|--xres)
xres="$1"
shift
;;
-y|--yres)
yres="$1"
shift
;;
-s|--subres)
subres="$1"
shift
;;
-t|--turd)
turd="$1"
shift
;;
-o)
scad="$1"
shift
;;
-n)
negate="-negate"
;;
-p|--prefix)
prefix="${1%.*}" # allow use of filename, but strip .ext
shift
;;
-l|--level|--levels)
levels="$1"
# if integer number of levels was given,
# convert that to a list of thresholds
# evenly spaced between 1 and 0
if [[ ${levels#*.} = $levels ]]
then
levels=`awk -v levels=$levels '
BEGIN {
s = (levels-0.5)/levels
for (i=levels-1; i>0; --i) {
s = s "," ((i-0.5)/levels)
}
printf s
}
' </dev/null`
fi
shift
;;
-v|--verbose)
verbose="true"
echo "verbose=true" 1>&2
;;
-h|--help)
echo "Usage: $myname {options} inputimagefile" 1>&2
echo "-a force alignment based on image (not object bounds)" 1>&2
echo "-c # set target max complexity (default $complex)" 1>&2
echo "-e # set max line-combining error in pixels (default $pixerr)" 1>&2
echo "-f # set highpass filter radius (default $filter)" 1>&2
echo "-g # set gamma (default $gamma)" 1>&2
echo "-h show this help message" 1>&2
echo "-l levs set level threshold, thresholds, or number of layers (default $levels)" 1>&2
echo "-n negate the image" 1>&2
echo "-o file set OpenSCAD output filename to file (default from input filename)" 1>&2
echo "-p pre set prefix for OpenSCAD module names (default from input filename)" 1>&2
echo "-s # set subpixel potrace resolution (default $subres)" 1>&2
echo "-t # set potrace turd size (default $turd)" 1>&2
echo "-v enable verbose output, keep temp files" 1>&2
echo "-x # set X resolution (default $xres)" 1>&2
echo "-y # set Y resolution (default $yres)" 1>&2
exit
;;
*)
if [ -n "$infile" ]
then
echo "Error: can only have one input filename; type $myname -h for usage" 1>&2
exit 1
fi
infile="$key"
if [ $prefix = "no_prefix_set" ]
then
prefix="${key%.*}" # strip .ext
prefix="${prefix##*/}" # strip leading path
prefix=`echo $prefix |tr '-' '_' |tr -cd '[_a-zA-Z0-9]'`
fi
if [ -z "$scad" ]
then
scad="${key%.*}.scad" # strip .ext, add .scad
fi
shift
;;
esac
done
if [ -z "$infile" ]
then
echo "Error: no input filename given; type $myname -h for usage" 1>&2
exit 1
fi
# remember reference image size
refxres=$xres
refyres=$yres
# empty the output file
>$scad
# process multiple-level stuff
curlev=0
if [ -n "${levels#*,}" ]
then
align=1 # force center based on image, not object bounds
fi
while [ -n "$levels" ]
do
level="${levels%%,*}" # extract a level
levels="${levels#$level}" # remove it from list
levels="${levels#,}" # remove comma after it
curlev=$(( $curlev + 1 )) # one more level
if [[ $align > 0 ]]
then
echo "Creating layer $curlev with level $level ..."
fi
# loop trying to meet complexity constraint
xres=$refxres
yres=$refyres
echo -n "Adjusting complexity:"
while true; do
echo -n " $xres"'x'"$yres"
if [ "$verbose" = "true" ]
then
echo ""
echo "trace2scad version $version" 1>&2
if [[ $align > 0 ]]
then
echo "--align" 1>&2
fi
echo "--complex $complex" 1>&2
echo "--filter $filter" 1>&2
echo "--gamma $gamma" 1>&2
echo "--level $level" 1>&2
if [[ -n $negate ]]
then
echo "--negate" 1>&2
fi
echo "--prefix $prefix" 1>&2
echo "--subres $subres" 1>&2
echo "--turd $turd" 1>&2
echo "--xres $xres" 1>&2
echo "--yres $yres" 1>&2
echo "input filename is $infile" 1>&2
echo "prefix is $prefix" 1>&2
echo "OpenSCAD output filename is $scad" 1>&2
echo "Converting image to" $pgm 1>&2
fi
convert $negate -gravity center -background white -gamma $gamma -adaptive-resize $xres'x'$yres $infile $ppm
if [ "$filter" != 0 ]
then
mkbitmap -f $filter -s 2 -t $level <$ppm >$pgm
else
mkbitmap -n -s 2 -t $level <$ppm >$pgm
fi
if [ "$verbose" = "true" ]
then
echo "Running potrace to make" $svg 1>&2
fi
# note potrace version dependence:
# potrace 1.11 says -a 0 to disable smoothing
# potrace 1.10 says -a -1 (or any negative) to disable smoothing
# -a -1 seem to work on both versions, so we just do that...
potrace --opaque -a -1 -u $subres --group -sct $turd <$pgm >$svg
# compute max possible bounding box...
# based on the actual PGM file dimensions
xdim=$(( `convert $pgm -print "%w" /dev/null` * $subres ))
ydim=$(( `convert $pgm -print "%h" /dev/null` * $subres ))
if [ "$verbose" = "true" ]
then
echo "Running sed to make" $raw 1>&2
fi
sed '1,/\/metadata/d
s/<g.*/<g>/
s/<path.*000000.*M/add /
s/<path.*ffffff.*M/sub /
/^fill/d
s/l//
s/z".*/ close/
s/<g>/begin/
s/<\/g>/end/
s/ /\
/g
/svg/d' <$svg >$raw
if [ "$verbose" = "true" ]
then
echo "Running awk to make" $scad 1>&2
fi
awk -v align=$align -v xdim=$xdim -v ydim=$ydim -v curlev=$curlev -v version=$version -v prefix=$prefix -v level=$level -v complex=$complex -v pixerr=$pixerr '
function r(x) { return(0 + x) }
function indent(x) {
for (xi=0; xi<x; ++xi) {
printf " "
}
}
function distfromline(x0, y0, x1, y1, x2, y2) {
# compute distance of x1,y1 from the line through x0,y0 and x2,y2
# as per http://en.wikipedia.org/wiki/Distance_from_a_point_to_a_line
t = (y2-y0)*x1 - (x2-x0)*y1 + x2*y0 - y2*x0
if (t < 0) t = -t
b = sqrt((y2-y0)^2 + (x2-x0)^2)
return(t / b)
}
function needed(x0, y0, x1, y1, x2, y2) {
# are all 3 points needed
if ((x0 == x1) && (x0 == x2)) return(0)
if ((y0 == y1) && (y0 == y2)) return(0)
if ((y0 != y1) && (y0 != y2)) {
s01 = (x0 - x1 + 0.0) / (y0 - y1)
s02 = (x0 - x2 + 0.0) / (y0 - y2)
if (s01 == s02) return(0)
}
if ((x0 != x1) && (x0 != x2)) {
s01 = (y0 - y1 + 0.0) / (x0 - x1)
s02 = (y0 - y2 + 0.0) / (x0 - x2)
if (s01 == s02) return(0)
}
if (distfromline(x0, y0, x1, y1, x2, y2) < pixerr) {
# check for already-absorbed points getting too
# far from the line
for (i=0; i<shadow; ++i) {
if (distfromline(x0, y0, shadx[i], shady[i], x2, y2) >= pixerr) {
# too far away
return(1)
}
}
return(0)
}
return(1)
}
BEGIN {
objno = 0
lev = 1
big = 10000000
minx = big
miny = big
maxx = -big
maxy = -big
nsp = 1
byebye = 0
shadow = 0
}
/begin/ {
++lev
nrec[nsp] = "{"
++nsp
next
}
/end/ {
--lev
if ((nrec[nsp-1] == "+") && (nrec[nsp-2] == "{")) {
# optimize out {x} becomes x
nrec[nsp-2] = nrec[nsp-1]
--nsp
} else {
nrec[nsp] = "}"
++nsp
}
next
}
/add/ {
++objno
typ[objno] = lev
nrec[nsp] = "+"
++nsp
pts = 0
curx = 0
cury = 0
ncur = "x"
next
}
/sub/ {
++objno
typ[objno] = -lev
nrec[nsp] = "-"
++nsp
pts = 0
curx = 0
cury = 0
ncur = "x"
next
}
/close/ {
# build string for polygon
# compute approximate convexity as number of turns
dx=0
dy=0
bufpts[objno] = pts
buf[objno] = sprintf("polygon([[%d,%d]", curx, cury)
convexity=2
for (i=2; i<=pts; ++i) {
buf[objno] = buf[objno] sprintf(",[%d,%d]", xpt[i], ypt[i])
ndx=(xpt[i-1]>xpt[i])
ndy=(ypt[i-1]>ypt[i])
if ((dx != ndx) || (dy != ndy)) ++convexity
dx=ndx
dy=ndy
}
buf[objno] = buf[objno] sprintf("], convexity=%d);", convexity)
ncur = ""
next
}
/[-0-9][0-9]*/ {
if (ncur == "x") {
prevx = curx
curx += r($1)
ncur = "y"
} else if (ncur == "y") {
prevy = cury
cury += r($1)
ncur = "x"
if (pts == 0) {
firstx = curx
firsty = cury
++pts
xpt[pts] = curx
ypt[pts] = cury
++allpts
} else if (((prevx != curx) || (prevy != cury)) &&
((firstx != curx) || (firsty != cury))) {
if ((pts > 2) &&
(needed(curx, cury, xpt[pts], ypt[pts], xpt[pts-1], ypt[pts-1]) < 1)) {
# get rid of previous point
shadx[shadow] = xpt[pts]
shady[shadow] = ypt[pts]
shadow = shadow + 1
++byebye
--pts
--allpts
} else {
# no points shadowed now
shadow = 0
}
++pts
xpt[pts] = curx
ypt[pts] = cury
++allpts
# update bounding box info
if (minx > curx) minx = curx
if (miny > cury) miny = cury
if (maxx < curx) maxx = curx
if (maxy < cury) maxy = cury
} else {
++byebye
}
# abort with no output if complexity exceeded
if (allpts > (0+complex)) {
exit
}
} else {
# this should never happen
print "Error parsing SVG generated by potrace."
}
next
}
/^/ {
next
}
END {
if (allpts < 2) {
# dummy output if no points
print "module " prefix "_" curlev "()"
print "{"
print " /* Generated by trace2scad version " version
print " http://aggregate.org/MAKE/TRACE2SCAD/"
print " There ws no model content with level " level
print " */"
print "}"
print ""
} else if (allpts < (0+complex)) {
# no output if complexity exceeded
print "module " prefix "_" curlev "()"
print "{"
print " /* Generated by trace2scad version " version
print " http://aggregate.org/MAKE/TRACE2SCAD/"
print " Optimized model has " allpts "/" (allpts+byebye) " original points"
print " */"
print " color([" level ", " level ", " level "])"
if (align > 0) {
print " assign(minx=0) /* polygon minx=" minx " */"
print " assign(miny=0) /* polygon miny=" miny " */"
print " assign(maxx=" xdim ") /* polygon maxx=" maxx " */"
print " assign(maxy=" ydim ") /* polygon maxy=" maxy " */"
} else {
print " assign(minx=" minx ")"
print " assign(miny=" miny ")"
print " assign(maxx=" maxx ")"
print " assign(maxy=" maxy ")"
}
print " assign(dx=maxx-minx)"
print " assign(dy=maxy-miny)"
print " assign(maxd=((dx>dy)?dx:dy))"
print " scale([1/maxd, 1/maxd, 1])"
print " translate([-minx-dx/2, -miny-dy/2, 0])"
print sprintf(" linear_extrude(height=1, convexity=%d)", allpts)
print " union() {"
i = 1
j = 1
k = 2
while (j < nsp) {
if (nrec[j] == "{") {
indent(k)
if (nrec[j+2] == "-") {
print "difference() {"
} else {
print "union() {"
}
++k
} else if (nrec[j] == "}") {
--k
indent(k)
print "}"
} else {
indent(k)
print buf[i]
++i
}
++j
}
print " }"
print "}"
print ""
}
}
' <$raw >$stmp
if [ -s "$stmp" ]
then
echo ""
break
fi
# reduce resolution to simplify
xres=`expr $xres '*' 9 '/' 10`
yres=`expr $yres '*' 9 '/' 10`
if [ "$verbose" = "true" ]
then
echo -n "Test complexity:"
fi
done
# add this layer to output file
cat $stmp >>$scad
done
# stick end on it all
awk -v curlev=$curlev -v version=$version -v prefix=$prefix -v complex=$complex '
BEGIN {
print "module " prefix "()"
print "{"
print " /* all layers combined, scaled to within a 1mm cube */"
print " scale([1, 1, 1/" curlev "])"
print " difference() {"
print " union() {"
for (i=0; i<curlev; ++i) {
print " scale([1,1," 2*(i+1) "]) translate([0,0,-0.5]) " prefix "_" (i+1) "();"
}
print " }"
print " translate([0,0,-" (curlev+1) "]) cube([2,2," (2*(curlev+1)) "],center=true);"
print " }"
print "}"
}
' </dev/null >>$scad
rm -f "$stmp"
if [ "$verbose" = "true" ]
then
echo "Leaving tmp files:" $ppm $pgm $svg $raw 1>&2
else
rm -f $ppm $pgm $svg $raw
fi