Legacy ImageMagick Discussions Archive

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#! /bin/bash

showimage() {
  display "${1:-}" &
}
cropcolorpermille() {
  # Function: Calculate permille part of pixels of color $2 in crop rectangle $3 of image $1
  # $1  $Image         image
  # $2  $Trimcolor     color to count
  # $3  $Cropgeometry  crop rectangle to search in
  # Output: Permille part of color in crop region
  
  local Image Trimcolor Cropgeometry
  local Colorcount Cropwidth Cropheight Permille
  
  Image="${1:-}"
  Trimcolor="${2:-}"
  Cropgeometry="${3:-}"
  
  Cropwidth=$(cut -dx -f1 <<< "$Cropgeometry")
  Cropheight=$(cut -dx -f2 <<< "$Cropgeometry" | cut -d+ -f1)

  Colorcount="$(convert "$Image" -crop "$Cropgeometry" txt: | grep -c "$Trimcolor")"
  # second way to count color, a bit slower.
#  Colorcount="$(convert "$Image" -crop "$Cropgeometry" -fill black +opaque "$Trimcolor"  -format %c histogram:info: | grep "$Trimcolor")"
#  Colorcount="$(awk '{print $1}' <<< "$Colorcount" | cut -d: -f1)"

  Permille=$((1000 * $Colorcount / ($Cropwidth*$Cropheight) ))
  echo "${Permille:-0}"
}
trim_hard3() {
  # Function: Trim all border with color $2 from image $1
  # Results in a maximal inner rectangle without border color.
  # $1  $Image      image
  # $2  $Trimcolor  color to trim. Default: transparent
  # Output: crop geometry
  
  local Image Trimcolor
  local Imagewidth Imageheight
  local Left         Right         Top         Bottom
  local Skipleft     Skipright     Skiptop     Skipbottom
  local Permilleleft Permilleright Permilletop Permillebottom Permillemax
  local Row Column Emptyrow Emptycolumn Partialcroppermille1 Partialcroppermille2 Width Height
  local Return
  local Debugmode Loopcount
  
  Image="${1:-}"
  Trimcolor="${2:-"#00000000"}"
  
  Imagewidth=$(convert  -format '%w'  $Image info:)
  Imageheight=$(convert -format '%h'  $Image info:)
  
  Left=0
  Top=0
  Right=$((Imagewidth-1))
  Bottom=$((Imageheight-1))
  
  # First cut with regular trim to save some time.
  # Add a colored border so trim uses the desired color. Afterward remove border from canvas to get correct geometry values. 
  Line="$(convert "$Image" -bordercolor "$Trimcolor" -border 1x1  -trim -set page '%[fx:page.width-2]x%[fx:page.height-2]+%[fx:page.x-1]+%[fx:page.y-1]' info:)"
  Left="$(awk '{print $4}' <<< "$Line" | cut -d+ -f2)"
  Top="$(awk '{print $4}' <<< "$Line" | cut -d+ -f3)"
  Right="$(awk '{print $3}' <<< "$Line" | cut -dx -f1)"
  Right="$((Left+Right-1))"
  Bottom="$(awk '{print $3}' <<< "$Line" | cut -dx -f2)"
  Bottom="$((Top+Bottom-1))"

  # Concept:
  # - Area check: [might be substituted with -connected-components]
  #   - Check for empty rows and columns, starting from the middle.
  #   - If there are empty rows or columns, divide area and skip the part with greater amount of $Trimcolor.
  # - Border check:
  #   - If no empty rows or colums are found, trim side with greatest permille (mean) value of $Trimcolor.
  # - Repeat
  while :; do
  
    ## Step 1: Area check ##
    # Check for a row/column that consists entirely of $Trimcolor and would split an inner rectangle. 
    # (A pure border check can fail in that case.)
    Width=$((Right-Left+1))
    Height=$((Bottom-Top+1))
    Halfwidth=$((Width/2))
    Halfheight=$((Height/2))
    # check for empty rows between Top and Bottom, starting from the middle.
    for ((i=1 ; i<Halfheight ; i++)); do
      Row=$((Halfheight-i))
      [ "1000" = "$(cropcolorpermille "$Image" "$Trimcolor" ${Width}x1+$Left+$((Top+$Row)) )" ]   && Emptyrow="$Row"       && break || Emptyrow=""
      Row=$((Halfheight+i-1))
      [ "1000" = "$(cropcolorpermille "$Image" "$Trimcolor" ${Width}x1+$Left+$((Top+$Row)) )" ]   && Emptyrow="$Row"       && break || Emptyrow=""
    done
     # check for empty columns between Left and Right, starting from the middle.
    for ((i=1 ; i<Halfwidth ; i++)); do
      Column=$((Halfwidth-i))
      [ "1000" = "$(cropcolorpermille "$Image" "$Trimcolor" 1x${Height}+$((Left+Column))+$Top)" ] && Emptycolumn="$Column" && break || Emptycolumn=""
      Column=$((Halfwidth+i-1))
      [ "1000" = "$(cropcolorpermille "$Image" "$Trimcolor" 1x${Height}+$((Left+Column))+$Top)" ] && Emptycolumn="$Column" && break || Emptycolumn=""
    done

    # If current geometry is splitted by empty row/column, skip the part with more $Trimcolor inside.
    Width=$((Right-Left+1))
    Height=$((Bottom-Top+1))
    [ "$Emptyrow" ] && {
      Partialcroppermille1=$(cropcolorpermille $Image "$Trimcolor" ${Width}x$((Emptyrow))+$Left+$Top)
      Partialcroppermille2=$(cropcolorpermille $Image "$Trimcolor" ${Width}x$((Height-Emptyrow+1))+$Left+$((Top + Emptyrow-1)) )
      [ "$Partialcroppermille1" -gt "$Partialcroppermille2" ] && Top=$((Top+Emptyrow+1)) || Bottom=$((Top+Emptyrow-1))
    }
    Width=$((Right-Left+1))
    Height=$((Bottom-Top+1))
    [ "$Emptycolumn" ] && {
      Partialcroppermille1=$(cropcolorpermille "$Image" "$Trimcolor" $((Emptycolumn))x${Height}+$Left+$Top)
      Partialcroppermille2=$(cropcolorpermille "$Image" "$Trimcolor" $((Width-Emptycolumn+1))x${Height}+$((Left+Emptycolumn-1))+$Top)
      [ "$Partialcroppermille1" -gt "$Partialcroppermille2" ] && Left=$((Left+Emptycolumn+1)) || Right=$((Left+Emptycolumn-1))
    }
    
    ## Step 2: Border check ##
    # If no empty rows/columns are left, trim side with greatest mean/permille of $Trimcolor
    [ "${Emptyrow}${Emptycolumn}" = "" ] && {
      # Get permille of $Trimcolor at each side
      Width=$((Right-Left+1))
      Height=$((Bottom-Top+1))
      Permilleleft=$(cropcolorpermille   $Image "$Trimcolor" 1x${Height}+$Left+$Top)
      Permilleright=$(cropcolorpermille  $Image "$Trimcolor" 1x${Height}+$Right+$Top)
      Permilletop=$(cropcolorpermille    $Image "$Trimcolor" ${Width}x1+$Left+$Top)
      Permillebottom=$(cropcolorpermille $Image "$Trimcolor" ${Width}x1+$Left+$Bottom)
    
      # Determine maximal permille value
      Permillemax=$(echo "
$Permilleleft
$Permilleright
$Permilletop
$Permillebottom
" | sort -n | tail -n1)
      [ "$Permillemax" = "0" ] && break # Ready
      
      # Remove side with greatest permille amount of $Trimcolor.
      [ "$Permillemax" = "$Permilleleft" ]   && Left=$((Left+1))
      [ "$Permillemax" = "$Permilleright" ]  && Right=$((Right-1))
      [ "$Permillemax" = "$Permilletop" ]    && Top=$((Top+1))
      [ "$Permillemax" = "$Permillebottom" ] && Bottom=$((Bottom-1))
    }
    
    # Out-of-range error
    { [ "$Left" -gt "$Right" ] || [ "$Top" -gt "$Bottom" ] ; } && {
      echo "Error: Failed to find an inner rectangle. Unuseable result: $((Right-Left+1))x$((Bottom-Top+1))+$Left+$Top" >&2
      Return=1
      Left=0
      Top=0
      Right=$((Imagewidth-1))
      Bottom=$((Imageheight-1))
      break
    }
    
    # Debugging: show intermediate results
    #Debugmode=yes
    [ "$Debugmode" ] && {
      Loopcount=$((Loopcount+1))
      [ "$Loopcount" = "10" ] && {
        Loopcount=0
        convert $Image -fill none -stroke red -strokewidth 1 -draw "rectangle $Left,$Top $Right,$Bottom" $Image.trim_hard.png
        showimage $Image.trim_hard.png
      }
    }
  done
  
  # Output of result
  #echo "$Left,$Top $Right,$Bottom"                     # "-draw rectangle" geometry
  echo $((Right-Left+1))x$((Bottom-Top+1))+$Left+$Top  # "-crop" geometry
  
  # Create image with red rectangle at crop coordinates and show it
  convert $Image -fill none -stroke red -strokewidth 1 -draw "rectangle $Left,$Top $Right,$Bottom" $Image.trim_hard.png
  showimage $Image.trim_hard.png
  
  return ${Return:-0}
}
trim_hard3 "$@"

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set SRC=34636180qx.png

%IMG7%magick ^
  %SRC% ^
  -fill Black +opaque White ^
  -negate ^
  -scale "1x^!" ^
  -crop 1x2@ +repage ^
  ( -clone 0 -flip ) ^
  -delete 0 ^
  +append ^
  x.png

Code: Select all

%IMG7%magick compare ^
  -metric RMSE ^
  -subimage-search ^
  x.png ^
  xc:Black ^
  NULL: