Make output concise by default.

tools/resources/optimize-png-files.sh

 #!/bin/bash
 # Copyright 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # The optimization code is based on pngslim (http://goo.gl/a0XHg)
 # and executes a similar pipleline to optimize the png file size.
 # The steps that require pngoptimizercl/pngrewrite/deflopt are omitted,
 # but this runs all other processes, including:
 # 1) various color-dependent optimizations using optipng.
@@ skipping 31 matching lines @@
 
 # Global variables for stats
 TOTAL_OLD_BYTES=0
 TOTAL_NEW_BYTES=0
 TOTAL_FILE=0
 PROCESSED_FILE=0
 
 declare -a THROBBER_STR=('-' '\\' '|' '/')
 THROBBER_COUNT=0
 
+SUBPROCESS=0
+
+# NoOp in subprocess, echo otherwise.
+function info {
+  if [ $SUBPROCESS -eq 0 ]; then
+    echo $@
+  fi
+}
+
 # Show throbber character at current cursor position.
 function throbber {
-  echo -ne "${THROBBER_STR[$THROBBER_COUNT]}\b"
+  info -ne "${THROBBER_STR[$THROBBER_COUNT]}\b"
   let THROBBER_COUNT=($THROBBER_COUNT+1)%4
 }
 
 # Usage: pngout_loop <file> <png_out_options> ...
 # Optimize the png file using pngout with the given options
 # using various block split thresholds and filter types.
 function pngout_loop {
   local file=$1
   shift
   local opts=$*
   if [ $OPTIMIZE_LEVEL == 1 ]; then
     for j in $(seq 0 5); do
       throbber
       pngout -q -k1 -s1 -f$j $opts $file
     done
   else
     for i in 0 128 256 512; do
       for j in $(seq 0 5); do
         throbber
         pngout -q -k1 -s1 -b$i -f$j $opts $file
       done
     done
   fi
 }
 
 # Usage: get_color_depth_list
 # Returns the list of color depth options for current optimization level.
 function get_color_depth_list {
   if [ $OPTIMIZE_LEVEL == 1 ]; then
     echo "-d0"

[msw, 2013/11/27 17:14:16]

nit: s/echo/info/? Should all remaining 'echo' usages be changed to 'info'?

[eustas, 2013/11/28 07:57:05]

Here echo is used to pass return value.

This function is always invoked like $(get_color_depth_list), so
its output will never be printed out.

I've replaced echo with info when output is not-essential, so when
multiple instanced work in parallel output will be clear (one line per processed
file).

There are some "gray" areas - error reporting. Currently I left
them untouched, so user will see if something goes wrong.

   else
     echo "-d1 -d2 -d4 -d8"
   fi
 }
 
 # Usage: process_grayscale <file>
 # Optimize grayscale images for all color bit depths.
 #
 # TODO(oshima): Experiment with -d0 w/o -c0.
 function process_grayscale {
-  echo -n "|gray"
+  info -n "|gray"
   for opt in $(get_color_depth_list); do
     pngout_loop $file -c0 $opt
   done
 }
 
 # Usage: process_grayscale_alpha <file>
 # Optimize grayscale images with alpha for all color bit depths.
 function process_grayscale_alpha {
-  echo -n "|gray-a"
+  info -n "|gray-a"
   pngout_loop $file -c4
   for opt in $(get_color_depth_list); do
     pngout_loop $file -c3 $opt
   done
 }
 
 # Usage: process_rgb <file>
 # Optimize rgb images with or without alpha for all color bit depths.
 function process_rgb {
-  echo -n "|rgb"
+  info -n "|rgb"
   for opt in $(get_color_depth_list); do
     pngout_loop $file -c3 $opt
   done
   pngout_loop $file -c2
   pngout_loop $file -c6
 }
 
 # Usage: huffman_blocks <file>
 # Optimize the huffman blocks.
 function huffman_blocks {
   local file=$1
-  echo -n "|huffman"
+  info -n "|huffman"
   local size=$(stat -c%s $file)
   local min_block_size=$DEFAULT_MIN_BLOCK_SIZE
   local limit_blocks=$DEFAULT_LIMIT_BLOCKS
 
   if [ $size -gt $LARGE_FILE_THRESHOLD ]; then
     min_block_size=$LARGE_MIN_BLOCK_SIZE
     limit_blocks=$LARGE_LIMIT_BLOCKS
   fi
   let max_blocks=$size/$min_block_size
   if [ $max_blocks -gt $limit_blocks ]; then
     max_blocks=$limit_blocks
   fi
 
   for i in $(seq 2 $max_blocks); do
     throbber
     pngout -q -k1 -ks -s1 -n$i $file
   done
 }
 
 # Usage: random_huffman_table_trial <file>
 # Try compressing by randomizing the initial huffman table.
 #
 # TODO(oshima): Try adjusting different parameters for large files to
 # reduce runtime.
 function random_huffman_table_trial {
-  echo -n "|random"
+  info -n "|random"
   local file=$1
   local old_size=$(stat -c%s $file)
   local trials_count=$DEFAULT_RANDOM_TRIALS
 
   if [ $old_size -gt $LARGE_FILE_THRESHOLD ]; then
     trials_count=$LARGE_RANDOM_TRIALS
   fi
   for i in $(seq 1 $trials_count); do
     throbber
     pngout -q -k1 -ks -s0 -r $file
   done
   local new_size=$(stat -c%s $file)
   if [ $new_size -lt $old_size ]; then
     random_huffman_table_trial $file
   fi
 }
 
 # Usage: final_comprssion <file>
 # Further compress using optipng and advdef.
 # TODO(oshima): Experiment with 256.
 function final_compression {
-  echo -n "|final"
+  info -n "|final"
   local file=$1
   if [ $OPTIMIZE_LEVEL == 2 ]; then
     for i in 32k 16k 8k 4k 2k 1k 512; do
       throbber
       optipng -q -nb -nc -zw$i -zc1-9 -zm1-9 -zs0-3 -f0-5 $file
     done
   fi
   for i in $(seq 1 4); do
     throbber
     advdef -q -z -$i $file
   done
-  echo -ne "\r"
+  info -ne "\r"
 }
 
 # Usage: get_color_type <file>
 # Returns the color type name of the png file. Here is the list of names
 # for each color type codes.
 # 0 : grayscale
 # 2 : RGB
 # 3 : colormap
 # 4 : gray+alpha
 # 6 : RGBA
 # See http://en.wikipedia.org/wiki/Portable_Network_Graphics#Color_depth
 # for details about the color type code.
 function get_color_type {
   local file=$1
   echo $(file $file | awk -F, '{print $3}' | awk '{print $2}')
 }
 
 # Usage: optimize_size <file>
 # Performs png file optimization.
 function optimize_size {
   tput el
   local file=$1
-  echo -n "$file "
+  info -n "$file "
 
   advdef -q -z -4 $file
 
   pngout -q -s4 -c0 -force $file $file.tmp.png
   if [ -f $file.tmp.png ]; then
     rm $file.tmp.png
     process_grayscale $file
     process_grayscale_alpha $file
   else
     pngout -q -s4 -c4 -force $file $file.tmp.png
     if [ -f $file.tmp.png ]; then
       rm $file.tmp.png
       process_grayscale_alpha $file
     else
       process_rgb $file
     fi
   fi
 
-  echo -n "|filter"
+  info -n "|filter"
   local old_color_type=$(get_color_type $file)
   optipng -q -zc9 -zm8 -zs0-3 -f0-5 $file -out $file.tmp.png
   local new_color_type=$(get_color_type $file.tmp.png)
   # optipng may corrupt a png file when reducing the color type
   # to grayscale/grayscale+alpha. Just skip such cases until
   # the bug is fixed. See crbug.com/174505, crbug.com/174084.
   # The issue is reported in
   # https://sourceforge.net/tracker/?func=detail&aid=3603630&group_id=151404&atid=780913
   if [[ $old_color_type == "RGBA" && $new_color_type =~ gray.* ]] ; then
     rm $file.tmp.png
-    echo -n "[skip opting]"
+    info -n "[skip opting]"
   else
     mv $file.tmp.png $file
   fi
   pngout -q -k1 -s1 $file
 
   huffman_blocks $file
 
   # TODO(oshima): Experiment with strategy 1.
-  echo -n "|strategy"
+  info -n "|strategy"
   if [ $OPTIMIZE_LEVEL == 2 ]; then
     for i in 3 2 0; do
       pngout -q -k1 -ks -s$i $file
     done
   else
     pngout -q -k1 -ks -s1 $file
   fi
 
   if [ $OPTIMIZE_LEVEL == 2 ]; then
     random_huffman_table_trial $file
@@ skipping 34 matching lines @@
 
   tput el
   if [ $new -lt $old ]; then
     echo -ne "$file : $old => $new ($diff bytes : $percent %)\n"
     mv "$tmp_file" "$file"
     let TOTAL_OLD_BYTES+=$old
     let TOTAL_NEW_BYTES+=$new
     let PROCESSED_FILE+=1
   else
     if [ $OPTIMIZE_LEVEL == 0 ]; then
-      echo -ne "$file : skipped\r"
+      info -ne "$file : skipped\r"
     fi
     rm $tmp_file
   fi
 }
 
 function optimize_dir {
   local dir=$1
   if $using_cygwin ; then
     dir=$(cygpath -w $dir)
   fi
@@ skipping 26 matching lines @@
   which $program > /dev/null 2>&1
   if [ $? != 0 ]; then
     echo "Couldn't find $program. Please download and install it from $url ."
     exit 1
   fi
 }
 
 function show_help {
   local program=$(basename $0)
   echo \
-"Usage: $program [options] dir ...
+"Usage: $program [options] <dir> ...
 
 $program is a utility to reduce the size of png files by removing
 unnecessary chunks and compressing the image.
 
 Options:
   -o<optimize_level>  Specify optimization level: (default is 1)
       0  Just run pngcrush. It removes unnecessary chunks and perform basic
          optimization on the encoded data.
       1  Optimize png files using pngout/optipng and advdef. This can further
          reduce addtional 5~30%. This is the default level.
       2  Aggressively optimize the size of png files. This may produce
          addtional 1%~5% reduction.  Warning: this is *VERY*
          slow and can take hours to process all files.
   -r<revision> If this is specified, the script processes only png files
                changed since this revision. The <dir> options will be used
                to narrow down the files under specific directories.
+  -s  Run as subprocess. This may be used to parallelize execution.
+      Usage: find <dir> -name \"*.png\" | xargs -n1 -P16 $program -s -o2
   -h  Print this help text."
   exit 1
 }
 
 if [ ! -e ../.gclient ]; then
   echo "$0 must be run in src directory"
   exit 1
 fi
 
 if [ "$(expr substr $(uname -s) 1 6)" == "CYGWIN" ]; then
   using_cygwin=true
 else
   using_cygwin=false
 fi
 
 OPTIMIZE_LEVEL=1
 # Parse options
-while getopts o:r:h opts
+while getopts o:r:h:s opts
 do
   case $opts in
     r)
       COMMIT=$(git svn find-rev r$OPTARG | tail -1) || exit
       if [ -z "$COMMIT" ] ; then
         echo "Revision $OPTARG not found"
         show_help
       fi
       ;;
     o)
       if [[ ! "$OPTARG" =~ [012] ]] ; then
         show_help
       fi
       OPTIMIZE_LEVEL=$OPTARG
       ;;
+    s)
+      let SUBPROCESS=1
+      ;;
     [h?])
       show_help;;
   esac
 done
 
 # Remove options from argument list.
 shift $(($OPTIND -1))
 
 # Make sure we have all necessary commands installed.
 install_if_not_installed pngcrush pngcrush
@@ skipping 20 matching lines @@
   TMP_DIR=$(cygpath -w $TMP_DIR)
 fi
 
 # Make sure we cleanup temp dir
 trap "rm -rf $TMP_DIR" EXIT
 
 # If no directories are specified, optimize all directories.
 DIRS=$@
 set ${DIRS:=$ALL_DIRS}
 
-echo "Optimize level=$OPTIMIZE_LEVEL"
+info "Optimize level=$OPTIMIZE_LEVEL"
+
 if [ -n "$COMMIT" ] ; then
  ALL_FILES=$(git diff --name-only $COMMIT HEAD $DIRS | grep "png$")
  ALL_FILES_LIST=( $ALL_FILES )
  echo "Processing ${#ALL_FILES_LIST[*]} files"
  for f in $ALL_FILES; do
    if [ -f $f ] ; then
      optimize_file $f
    else
      echo "Skipping deleted file: $f";
    fi
  done
+elif [ $SUBPROCESS -eq 1 ]; then
+  for f in $DIRS; do
+    optimize_file $f
+  done
 else
   for d in $DIRS; do
     echo "Optimizing png files in $d"
     optimize_dir $d
     echo
   done
 fi
 
 # Print the results.
+if [ $SUBPROCESS -eq 1 ]; then
+  exit 0
+fi
+
 if [ $PROCESSED_FILE == 0 ]; then
   echo "Did not find any files (out of $TOTAL_FILE files)" \
        "that could be optimized" \
        "in $(date -u -d @$SECONDS +%T)s"
 else
   let diff=$TOTAL_OLD_BYTES-$TOTAL_NEW_BYTES
   let percent=$diff*100/$TOTAL_OLD_BYTES
   echo "Processed $PROCESSED_FILE files (out of $TOTAL_FILE files)" \
        "in $(date -u -d @$SECONDS +%T)s"
   echo "Result : $TOTAL_OLD_BYTES => $TOTAL_NEW_BYTES bytes" \
        "($diff bytes : $percent %)"
 fi