Process Android images

resize_android_images.py

'''
requires imagemagick to be installed. http://www.imagemagick.org/script/index.php
'''
import os
import sys
import subprocess
import argparse

# defines the input we want to use.  Change the directory name or the target DPI to set this.  
inputDirName = "drawable-xhdpi"
inputDirSize = 320.0

# the directories we want to output to with the dpi size
outputs = {
	"drawable-xxhdpi": 480.0,
	"drawable-xhdpi": 320.0,
	"drawable-hdpi": 240.0, 
	"drawable-mdpi": 160.0,
	"drawable-ldpi": 120.0
}

def resizeAndSave(imagePath, savePath, resizeAmount):
	percentage = str(resizeAmount * 100) + "%"
	command = ["convert", imagePath, "-resize", percentage, savePath]
	subprocess.call(command)

def resizeImages(inputDirectory):
	baseDir = inputDirectory + inputDirName
	fileList = os.listdir(baseDir)
	imagesToProcess = []
	for fileName in fileList:
		inputFile = baseDir + "/" + fileName
		if(validFile(inputFile)):
			imagesToProcess.append(fileName)

	totalFiles = len(imagesToProcess)
	processed = 0
	for fileName in imagesToProcess:
		for output in outputs:
			if output != inputDirName:
				outputDir = inputDirectory + output
				if os.path.exists(outputDir) == False:
					os.makedirs(outputDir)
				percentage = outputs[output]/inputDirSize
				inputFile = baseDir + "/" + fileName
				outputFile = outputDir + "/" + fileName
				resizeAndSave(inputFile, outputFile, percentage)
		processed += 1
		complete = float(processed)/float(totalFiles)
 		percentageComplete = str(int(complete * 100.0))
 		outputText = percentageComplete + "% : " + str(processed) + " of " + str(totalFiles)
 		sys.stdout.write('\r' + outputText)
 		sys.stdout.flush()
 	print "\nDone: processed " + str(totalFiles) + " files"

def validFile(filePath):
	extension = os.path.splitext(filePath)[1].lower()
	if(extension == ".png" or extension == ".jpeg" or extension == ".jpg"):
		return True
	return False

def checkArgsAndGetDir(args):
	if(args.resdir == None):
		print "Not enough arguments. You need to supply a res directory"
		exit(1)

	elif os.path.isdir(args.resdir) == False:
		print args.resdir + " is not a directory"
		exit(1)

	inputDirectory = args.resdir
	if(args.input != None):
		global inputDirName
		inputDirName = str(args.input)
		inputDirSize = outputs[inputDirName]

	if(inputDirectory[-1:] != "/"):
		inputDirectory = inputDirectory + "/"
	if os.path.isdir(inputDirectory + inputDirName) == False:
		print "Res folder contains no " + inputDirName + " directory"
		exit(1)

	output = {}
	return inputDirectory

def checkImageMagick():
	# check for image magic
	try:
		subprocess.check_call(["convert"], stdout=open(os.devnull, "wb"))
	except subprocess.CalledProcessError:
		print "something went wrong with imagemagick"
		exit(1)
	except OSError:
		print "imagemagick needs to be installed. You can find it at: http://www.imagemagick.org/script/command-line-tools.php"
		exit(1)

def start():
	parser = argparse.ArgumentParser(description="A utility to resize images for android.")
	parser.add_argument("-r", "--resdir", metavar="", required=True, type=str, help="The res directory for the images")

	choices = []
	helpText = "valid options: "
	for key in outputs:
		choices.append(key)
		helpText += key + " "
	parser.add_argument("-i", "--input", metavar="", default="drawable-xhdpi", choices=choices, help="The image directory to use for sampling. " + helpText)
	args = parser.parse_args()

	checkImageMagick()
	inputDirectory = checkArgsAndGetDir(args)
	resizeImages(inputDirectory)

start()