A simple script to port iOS retina images to the appropriate Android density buckets.

Porting an iOS application to Android is a time-consuming task, especially when you have to manually resize 1000 images from iPhone/iPad dimensions to Android density buckets and screen sizes. This script aims to save as much time as possible by automatically resizing these images for you.

ImageMagick

On Mac OS X, the easiest way to install ImageMagick is with Homebrew:

brew install imagemagick

1. Put the ios2android bash script somewhere in your path

2. Copy the retina iOS images you want to convert into an empty directory.

3. From a terminal, cd into that directory and run:

$ ios2android

The script will evaluate each file in the directory, and determine if it is targeted for phone or tablet devices based on the filename. It will then create resized versions of the images and place them into the appropriately named density bucket folders. The script will also compensate for filenames that are not valid in android (such as images starting with numbers or containing hyphens).

Once the script is complete, simply copy the new folders into your Android project and you will have the equivalent of the iOS images. Way easier than manually scaling it yourself!

You can also create phone images directly from iPad images by specifying a scaling factor to use. Take a look at example 3 below.

1. A directory containing the following files:

[email protected]         (510 x 490 pixels)
intro_text@2x~ipad.png    (1222 x 1152 pixels)

will result in:

drawable-mdpi/intro_text.png          (255 x 245 pixels - 50%)
drawable-hdpi/intro_text.png          (383 x 368 pixels - 75%)
drawable-xhdpi/intro_text.png         (574 x 551 pixels - 112.5%)
drawable-large-mdpi/intro_text.png    (611 x 576 pixels - 50%)
drawable-large-hdpi/intro_text.png    (917 x 864 pixels - 75%)
drawable-large-xhdpi/intro_text.png   (1375 x 1296 pixels - 112.5%)

2. iPhone 5 4" images are treated the same as iPhone for 3.5" images, so a directory containing the following files:

[email protected]         (510 x 490 pixels)

will result in:

drawable-mdpi/intro_text.png          (255 x 245 pixels - 50%)
drawable-hdpi/intro_text.png          (383 x 368 pixels - 75%)
drawable-xhdpi/intro_text.png         (574 x 551 pixels - 112.5%)

3. You can also specify a pre-scaling factor on the command line that is useful to create high-resolution phone images based solely on retina iPad images.

For example, if the iPad resources in your iOS project are 40% larger than the equivalent phone resources, you can specify a percentage on the command line when running the scripts to automatically create phone-sized images from just the iPad resources.

A directory containing the following files:

intro_text@2x~ipad.png    (1000 x 1000 pixels)

when processed with a 60% pre-scaling factor:

$ ios2android 0.60

will result in:

drawable-mdpi/intro_text.png          (300 x 300 pixels - 60% * 50%)
drawable-hdpi/intro_text.png          (450 x 450 pixels - 60% * 75%)
drawable-xhdpi/intro_text.png         (675 x 675 pixels - 60% * 112.5%)
drawable-xxhdpi/intro_text.png        (900 x 900 pixels - 60% * 150%)
drawable-large-mdpi/intro_text.png    (500 x 500 pixels - 50%)
drawable-large-hdpi/intro_text.png    (750 x 750 pixels - 75%)
drawable-large-xhdpi/intro_text.png   (1125 x 1125 pixels - 112.5%)

The MIT License (MIT)

Copyright (c) 2013 Ninjanetic Design Inc.

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

For more information on re-scaling iOS images to Android, you can find a great web tool here:

http://www.teehanlax.com/tools/density/

ios2android was created by Jason Adams of Ninjanetic Design Inc.