#!/bin/bash # # Developed by Fred Weinhaus 11/21/2008 .......... revised 4/25/2015 # # ------------------------------------------------------------------------------ # # Licensing: # # Copyright © Fred Weinhaus # # My scripts are available free of charge for non-commercial use, ONLY. # # For use of my scripts in commercial (for-profit) environments or # non-free applications, please contact me (Fred Weinhaus) for # licensing arrangements. My email address is fmw at alink dot net. # # If you: 1) redistribute, 2) incorporate any of these scripts into other # free applications or 3) reprogram them in another scripting language, # then you must contact me for permission, especially if the result might # be used in a commercial or for-profit environment. # # My scripts are also subject, in a subordinate manner, to the ImageMagick # license, which can be found at: http://www.imagemagick.org/script/license.php # # ------------------------------------------------------------------------------ # #### # # USAGE: bilinearwarp [-f format] [-v vpmode] [-b bgcolor] "x1,y1 x2,y2 x3,y3 x4,y4" infile outfile # USAGE: bilinearwarp [-h or -help] # # OPTIONS: # # "x1,y1 x2,y2 ..." four and only four control point x,y coordinates; # these are where the corners of input image are # desired in the output image; must be ordered clockwise # starting with the point corresponding to the upper # left corner of input image; floats>=0; # list must be specified just prior to infile # -f format format for output size; B or box (for bounding box) # or I or input (for same as input); default=box # -v vpmode any valid IM virtual-pixel mode; default=black # -b bgcolor background color when virtual-pixel is set to # background; Any valid IM color; default=black # ### # # NAME: BILINEARWARP # # PURPOSE: To generate a proper four-point bilinear warp of the input image. # # DESCRIPTION: BILINEARWARP generate a proper four-point bilinear warp of the # input image using the corners of the input image and the specified # corresponding coordinates where it is desire that those corner points be # located in the output image. The input coordinates are not specified as # they will be found from the image dimensions. The four output x,y coordinates # must be specified in clockwise order starting with the corresponding point to # the upper left corner of the input image. # # OPTIONS: # # "x1,y1 x2,y2 x3,y3 x4,y4" ... LIST of x,y coordinates in the output image # that correspond to where the corners of the input image are desired to be # located. The input coordinates are not specified as they will be found from # the image dimensions. The four output x,y coordinates must be specified in # clockwise order starting with the corresponding point to the upper left # corner of the input image. Values may be floats>=0. # # -f format ... FORMAT for output size. The choices are to make the output the # same size as the input (value=I or input) or to make the output the size of # the bounding box around the set of specified output control point coordinates # (value=B or box). The default is B (bounding box). # # -v vpmode ... VPMODE is any valid IM virtual-pixel method. # The default is black. # # -b bgcolor... BGCOLOR is the fill color for the background area outside # of the warped image when the virtual-pixel method is specified as background. # Any valid IM color may be used. Values should be enclosed in quotes if not # color names. See http://imagemagick.org/script/color.php # # Mathematical Background # # NOTE: This script may be slow due to the use of -fx. # # CAVEAT: No guarantee that this script will work on all platforms, nor that # trapping of inconsistent parameters is complete and foolproof. Use At Your # Own Risk. # ###### # # set default value format="box" #box or input vpmode="black" #virtual-pixel mode bgcolor="black" #background color when vpmode=background # set directory for temporary files dir="." # suggestions are dir="." or dir="/tmp" # set up functions to report Usage and Usage with Description PROGNAME=`type $0 | awk '{print $3}'` # search for executable on path PROGDIR=`dirname $PROGNAME` # extract directory of program PROGNAME=`basename $PROGNAME` # base name of program usage1() { echo >&2 "" echo >&2 "$PROGNAME:" "$@" sed >&2 -e '1,/^####/d; /^###/g; /^#/!q; s/^#//; s/^ //; 4,$p' "$PROGDIR/$PROGNAME" } usage2() { echo >&2 "" echo >&2 "$PROGNAME:" "$@" sed >&2 -e '1,/^####/d; /^######/g; /^#/!q; s/^#*//; s/^ //; 4,$p' "$PROGDIR/$PROGNAME" } # function to report error messages, usage and exit errMsg() { echo "" echo $1 echo "" usage1 exit 1 } # function to test for minus at start of value of second part of option 1 or 2 checkMinus() { test=`echo "$1" | grep -c '^-.*$'` # returns 1 if match; 0 otherwise [ $test -eq 1 ] && errMsg "$errorMsg" } # function to test if valid positive float point pair testFloatPair() { v1=`echo $1 | cut -d, -f1` v2=`echo $1 | cut -d, -f2` test1=`expr "$v1" : '^[.0-9][.0-9]*$'` test2=`expr "$v2" : '^[.0-9][.0-9]*$'` [ $test1 -eq 0 -o $test2 -eq 0 ] && errMsg "$1 IS NOT A VALID POINT PAIR" } # test for correct number of arguments and get values if [ $# -eq 0 ] then # help information echo "" usage2 exit 0 elif [ $# -gt 9 ] then errMsg "--- TOO MANY ARGUMENTS WERE PROVIDED ---" else while [ $# -gt 0 ] do # get parameter values case "$1" in -h|-help) # help information echo "" usage2 exit 0 ;; -f) # get format shift # to get the next parameter # test if parameter starts with minus sign errorMsg="--- INVALID FORMAT SPECIFICATION ---" checkMinus "$1" case "$1" in B) format="box";; b) format="box";; box) format="box";; I) format="input";; i) format="input";; input) format="input";; *) errMsg="--- UNKNOWN FORMAT ---" esac ;; -v) # get vpmode shift # to get the next parameter # test if parameter starts with minus sign errorMsg="--- INVALID VIRTUAL-PIXEL SPECIFICATION ---" checkMinus "$1" vpmode="$1" ;; -b) # get bgcolor shift # to get the next parameter # test if parameter starts with minus sign errorMsg="--- INVALID BACKGROUND COLOR SPECIFICATION ---" checkMinus "$1" bgcolor="$1" ;; -) # STDIN and end of arguments break ;; -*) # any other - argument errMsg "--- UNKNOWN OPTION ---" ;; *) # end of arguments break ;; esac shift # next option done fi # extract and test point pair values # get plist, infile and outfile parms="$1" infile="$2" outfile="$3" # test that infile provided [ "$infile" = "" ] && errMsg "NO INPUT FILE SPECIFIED" # test that outfile provided [ "$outfile" = "" ] && errMsg "NO OUTPUT FILE SPECIFIED" # process plist # first pattern below replaces all occurrences of commas and spaces with a space => 1 2 3 4 5 6 # second pattern below replaces the first occurrence of a space with a comma => 1,2[ 3 4][ 5 6] - ignore [], they are for emphasis only # third pattern below looks for all space number space number pairs and replaces them with a space followed by number1,number2 => 1,2 3,4 5,6 set - `echo "$parms" | sed 's/[, ][, ]*/ /g; s/ /,/; s/ \([^ ]*\) \([^ ]*\)/ \1,\2/g'` # test for valid positive floats for x and y index=0 plist="" while [ $# -gt 0 ] do testFloatPair $1 plist="$plist $1" shift index=`expr $index + 1` done #remove leading space from plist plist=`echo "$plist" | sed -n 's/ [ ]*\(.*\)/\1/p'` [ "$plist" = "" ] && errMsg "--- NO POINT PAIRS WERE PROVIDED ---" # test if 4 x,y control points numpts=`echo "$plist" | wc -w` [ $numpts -ne 4 ] && errMsg "--- REQUIRES 4 OUTPUT X,Y CONTROL POINTS ---" # separate control points point0=`echo "$plist" | cut -d\ -f1` point1=`echo "$plist" | cut -d\ -f2` point2=`echo "$plist" | cut -d\ -f3` point3=`echo "$plist" | cut -d\ -f4` # separate each point into x and y values x0=`echo "$point0" | cut -d, -f1` y0=`echo "$point0" | cut -d, -f2` x1=`echo "$point1" | cut -d, -f1` y1=`echo "$point1" | cut -d, -f2` x2=`echo "$point2" | cut -d, -f1` y2=`echo "$point2" | cut -d, -f2` x3=`echo "$point3" | cut -d, -f1` y3=`echo "$point3" | cut -d, -f2` # setup temporary images and auto delete upon exit # use mpc/cache to hold input image temporarily in memory tmpA="$dir/bilinearwarp_$$.mpc" tmpB="$dir/bilinearwarp_$$.cache" trap "rm -f $tmpA $tmpB;" 0 trap "rm -f $tmpA $tmpB; exit 1" 1 2 3 15 trap "rm -f $tmpA $tmpB; exit 1" ERR if convert -quiet "$infile" +repage "$tmpA" then # get last x and y pixel nx=`convert $tmpA -format "%[fx:w-1]" info:` ny=`convert $tmpA -format "%[fx:h-1]" info:` else errMsg "--- FILE $infile DOES NOT EXIST OR IS NOT AN ORDINARY FILE, NOT READABLE OR HAS ZERO SIZE ---" fi # BACKGROUND INFORMATION # # Test of proper bilinear interpolation as inverse transformation # This inverts the 1 1/2 order transformation, which involves solving a quadratic equation # This test only works on the whole image # # the forward bilinear transformation from rectangle to quadrilateral is of the form # u,v are input (rectangle) coordinates # x,y are output (quadrilateral) coordinates # x = a0 + (a1 * u) + (a2 * v) + (a3 * u * v) # y = b0 + (b1 * u) + (b2 * v) + (b3 * u * v) # # we want to find and use the inverse equation # u = F(x,y) # v = G(x,y) # rectangle coordinates ordered clockwise from upper left corner # 0 1 # _______________ # | | # | | # | | # | | # | | # |______________| # # 3 2 if [ "$format" = "box" ]; then # compute bounding box of output points maxx=`convert xc: -format "%[fx:max($x3,max($x2,max($x1,max($x0,-1000000))))]" info:` minx=`convert xc: -format "%[fx:min($x3,min($x2,min($x1,min($x0,1000000))))]" info:` maxy=`convert xc: -format "%[fx:max($y3,max($y2,max($y1,max($y0,-1000000))))]" info:` miny=`convert xc: -format "%[fx:min($y3,min($y2,min($y1,min($y0,1000000))))]" info:` ww=`convert xc: -format "%[fx:floor($maxx-$minx)]" info:` hh=`convert xc: -format "%[fx:floor($maxy-$miny)]" info:` # compute output coords relative to bounding box x0=`convert xc: -format "%[fx:$x0-$minx]" info:` y0=`convert xc: -format "%[fx:$y0-$miny]" info:` x1=`convert xc: -format "%[fx:$x1-$minx]" info:` y1=`convert xc: -format "%[fx:$y1-$miny]" info:` x2=`convert xc: -format "%[fx:$x2-$minx]" info:` y2=`convert xc: -format "%[fx:$y2-$miny]" info:` x3=`convert xc: -format "%[fx:$x3-$minx]" info:` y3=`convert xc: -format "%[fx:$y3-$miny]" info:` fi # compute coefficients # substitute u,v=0,0 a0=$x0 # substitute u,v=nx,0 a1=`convert xc: -format "%[fx:($x1 - $x0)/$nx]" info:` # substitute u,v=0,ny a2=`convert xc: -format "%[fx:($x3 - $x0)/$ny]" info:` # substitute u,v=nx,ny a3=`convert xc: -format "%[fx:($x0 - $x1 - $x3 + $x2)/($nx * $ny)]" info:` # substitute u,v=0,0 b0=$y0 # substitute u,v=nx,0 b1=`convert xc: -format "%[fx:($y1 - $y0)/$nx]" info:` # substitute u,v=0,ny b2=`convert xc: -format "%[fx:($y3 - $y0)/$ny]" info:` # substitute u,v=nx,ny b3=`convert xc: -format "%[fx:($y0 - $y1 - $y3 + $y2)/($nx * $ny)]" info:` # calculate quadratic coefficient constants # solve for u in x equation # then solve quadratic in v and take plus sign choice A=`convert xc: -format "%[fx:($b2 * $a3) - ($b3 * $a2)]" info:` B1=`convert xc: -format "%[fx:(($b0 * $a3) - ($b3 * $a0)) + (($b2 * $a1) - ($b1 * $a2))]" info:` C1=`convert xc: -format "%[fx:($b0 * $a1) - ($b1 * $a0)]" info:` debug="false" if $debug; then echo "x0,y0 = $x0,$y0" echo "x1,y1 = $x1,$y1" echo "x2,y2 = $x2,$y2" echo "x3,y3 = $x3,$y3" echo "a0=$a0" echo "a1=$a1" echo "a2=$a2" echo "a3=$a3" echo "b0=$b0" echo "b1=$b1" echo "b2=$b2" echo "b3=$b3" echo "A=$A" echo "B1=$B1" echo "C1=$C1" fi # set up for transparency if [ "$vpmode" = "transparent" ]; then channels="-channel rgba -matte" xcolor="none" else channels="" xcolor="" fi # set "skycolor" to same as either background or transparent if [ "$vpmode" = "transparent" ]; then skycolor="none" elif [ "$vpmode" = "black" -o "$vpmode" = "white" -o "$vpmode" = "gray" ]; then skycolor="$vpmode" elif [ "$vpmode" = "background" ]; then skycolor="$bgcolor" else skycolor="black" fi # for fx: i,j=output coords (replacing x,y) and is,il=input coords (replacing u,v) # condition for skycolor is when square root argument (rt) is negative if [ "$format" = "box" ]; then convert \( -size ${ww}x${hh} xc:$xcolor \) \( $tmpA $channels \) \ -virtual-pixel $vpmode -background $bgcolor -monitor \ -fx "bb=$B1+($b3*i)-($a3*j); cc=$C1+($b1*i)-($a1*j); rt=(bb*bb)-(4*$A*cc); il=(-bb+sqrt(rt))/(2*$A); is=(i-$a0-($a2*il))/($a1+($a3*il)); rt<0?$skycolor:v.p{is,il}" "$outfile" elif [ "$format" = "input" ]; then convert $tmpA $channels -virtual-pixel $vpmode \ -background $bgcolor -monitor \ -fx "bb=$B1+($b3*i)-($a3*j); cc=$C1+($b1*i)-($a1*j); rt=(bb*bb)-(4*$A*cc); il=(-bb+sqrt(rt))/(2*$A); is=(i-$a0-($a2*il))/($a1+($a3*il)); rt<0?$skycolor:u.p{is,il}" "$outfile" fi exit 0