Image Magick

Windows/Linux command line tools and C libs to do image manipulation. Very powerful. Very fast. Deliciously bug-free. Open source.

See http://www.imagemagick.org/

See also TclMagick

Netpbm offers much the same functionality as ImageMagick in regard to conversion between formats. Both are open-sourced.

PR Here's an example how I use Tcl/Tk with ImageMagick to convert RAW grayscale images to JPEG. I'm calling this script from a BAT file, see Droplets.

Gray2Jpeg.tcl

  #!env wish

  proc Gray2Jpeg {} {
  # the command line to execute
    global gFilNam gDir gRows gCols gDepth gArgs gKeep
    set lOWD [ pwd ]
    cd $gDir
    eval exec env convert.exe -depth $gDepth -size $gRows\x$gCols $gArgs GRAY:$gFilNam [ file rootname $gFilNam ].jpg
    cd $lOWD
    WriteConf
    if { $gKeep == 0 } { exit }
  }

  proc ChooseFile {} {
  # select file to convert
    global gFilNam gDir
    set lFilNamL [ tk_getOpenFile -filetypes { { RAW { .gray .raw } } } \
                   -initialfile $gFilNam -initialdir $gDir ]
    if { [ string length $lFilNamL ] > 0 } {
      set gFilNam [ file tail $lFilNamL ]
      set gDir [ file dirname $lFilNamL ]
      WriteConf
    }
  }

  proc WriteConf {} {
  # write conf file
    global env gFilNam gDir gConfFil gRows gCols gDepth gArgs gKeep
    set gConfFil [ open [ file join $env(HOME) ".Gray2Jpeg.tcl.conf" ] "w" ]
    puts $gConfFil [ list set gDir    $gDir ]
    puts $gConfFil [ list set gFilNam $gFilNam ]
    puts $gConfFil [ list set gRows   $gRows ]
    puts $gConfFil [ list set gCols   $gCols ]
    puts $gConfFil [ list set gDepth  $gDepth ]
    puts $gConfFil [ list set gArgs   $gArgs ]
    puts $gConfFil [ list set gKeep   $gKeep ]
    close $gConfFil
  }

  # default parameters
  set gDir "."
  set gFilNam ""
  set gRows 0
  set gCols 0
  set gDepth 8
  set gArgs ""
  set gKeep 0
  # get parameters from conf file
  catch { source [ file join $env(HOME) ".Gray2Jpeg.tcl.conf" ] }

  # build window
  labelframe .lf -text "Raw Gray Image" -padx 2 -pady 2
  label .lf.l11 -text "Filename: " -padx 2 -pady 2
  label .lf.l12 -textvariable ::gFilNam -relief sunken -bd 1 -width 20 -anchor e -padx 2 -pady 2
  button .lf.b13 -text "..." -command ChooseFile -bd 1 -padx 2 -pady 2
  label .lf.l21 -text "Rows: " -padx 2 -pady 2
  entry .lf.e23 -textvariable ::gRows -width 5 -justify right
  label .lf.l31 -text "Columns: " -padx 2 -pady 2
  entry .lf.e33 -textvariable ::gCols -width 5 -justify right
  label .lf.l41 -text "Depth: " -padx 2 -pady 2
  entry .lf.e43 -textvariable ::gDepth -width 5 -justify right
  label .lf.l51 -text "Arguments: " -padx 2 -pady 2
  entry .lf.e52 -textvariable ::gArgs
  frame .f
  checkbutton .f.cb -variable ::gKeep
  label .f.l -text "Keep Open" -bd 0 -font { { system } 7 }
  button .bOK -text "  OK  " -command Gray2Jpeg -padx 2 -pady 2
  button .bEX -text "Cancel" -command exit -padx 2 -pady 2

  # display
  wm resizable . 0 0
  grid .lf.l11 .lf.l12 .lf.b13 -sticky ew
  grid .lf.l21       x .lf.e23 -sticky ew
  grid .lf.l31       x .lf.e33 -sticky ew
  grid .lf.l41       x .lf.e43 -sticky ew
  grid .lf.l51 .lf.e52       - -sticky ew
  grid .lf  - -    - -    - - -sticky news
  grid .f   x x .bEX x .bOK x -sticky news
  grid .f.l .f.cb

  # start up
  if { $argc > 0 } {
    set gFilNam [ file tail [ lindex $argv 0 ] ]
    set gDir [ file dirname [ lindex $argv 0 ] ]
  }

  #console show