Android drawables conversion

.bashrc

#EXAMPLE $ vert -d res/drawable-mdpi -d res/drawable-hdpi res/drawable-xhdpi-v14/*.png
alias vert='python ~/git/android_tools/drawable_convert.py'

drawable_convert.py

#!/usr/bin/python

import sys
import argparse
import os
import re
from sets import Set

'''
A simple script to create lower-resolution Android drawables from higher-resolution ones.

For example, given a batch of -xhdpi images, you can generate -hdpi and -mdpi images.

This makes it possible to only export highest-resolution artwork from image authoring tools, and
automate the rest.

Usage:

   drawable_convert.py -d res/drawable-mdpi -d res/drawable-hdpi res/drawable-xhdpi-v14/select*.png
   
   ... will take select*.png from xhdpi and place versions into mdpi and hdpi folders.
   
   Correct resize ratios are computed based on resource directory names.
   
   Actual scaling is done by ImageMagick's convert command.
'''
# We are not converting 9 patches!!!!!!! (will replace with regex later)
allowed_chars = Set('012345678abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_-./')

class Converter:
  def __init__(self, dstList):
    print u'Dst list: {0}'.format(dstList)
    self.mDstList = dstList
    
  def convert(self, src):
    for dstpath in self.mDstList:
      if Set(src).issubset(allowed_chars):
        (srcpath, srcname) = os.path.split(src)
        dst = os.path.join(dstpath, srcname)
        self.convertOne(src, dst)
      else:
        print src +"This does not convert 9 patch files"
    
  def convertOne(self, src, dst):
    print u'\n*****\n{0} to {1}\n*****\n'.format(src, dst)
    '''
    Determine relative density
    '''
    srcDpi = self.getDpi(src)
    dstDpi = self.getDpi(dst)
    
    if srcDpi < dstDpi:
      print u'NOT converting from {0}dpi to {1}dpi'.format(srcDpi, dstDpi)
    else:
      factor = dstDpi*100/srcDpi
      print u'Converting from {0}dpi to {1}dpi, {2}%'.format(srcDpi, dstDpi, factor)
      cmd = u'convert -verbose "{0}" -resize "{2}%x{2}%" "{1}"'.format(src, dst, factor)
      os.system(cmd)
    
  def getDpi(self, f):
    p = os.path.dirname(f)
    if re.match('.*drawable.*\\-mdpi.*', p):
      return 160
    elif re.match('.*drawable.*\\-hdpi.*', p):
      return 240
    elif re.match('.*drawable.*\\-xhdpi.*', p):
      return 320
    else:
      raise ValueError(u'Cannot determine densitiy for {0}'.format(p))

if __name__ == "__main__":
  '''
  Parse command line arguments
  '''
  parser = argparse.ArgumentParser(description='Converts drawable resources in Android applications')
  parser.add_argument('-d', dest='DST', action='append', required=True, help='destination directory')
  parser.add_argument('src', nargs='+', help='files to convert (one or more)')
  args = parser.parse_args()

  cv = Converter(args.DST)
  for src in args.src:
    cv.convert(src)


'''


if [ $# -lt 1 ] ; then
  echo "Usage: $0 file_list"
  exit 1
fi

for f in $*
do
  echo "File: ${f}"
  convert -verbose "${f}" -resize "75%x75%" "../drawable-hdpi/${f}"
  convert -verbose "${f}" -resize "50%x50%" "../drawable-mdpi/${f}"
done

'''

gistfile1.md

###Android drawables conversion

This script currently supports mdpi and higher, and I will be looking to add ldpi later on.

The best case scenario would be xhdpi -> hdip -> mdpi

Some sample android targets

This script requires imagemagick

Original python script was forked from (kmansoft) https://gist.github.com/2771791