For NativeScript - Process all images from a source folder and creates suitably sized images in the app's target folder

mkgraphics.js

// based around the setup in https://www.npmjs.com/package/nativescript-media-generator
// all %s come from it
// npm install imagemagick async
// update the source and target paths
// then run node mkgraphics.js
// It should put correctly sized images in the right folders

var im = require('imagemagick');
var fs = require("fs");
var path = require("path");
var async = require("async");

var sourcePath = path.resolve("./tipple-graphics/graphics");
var targetPath = path.resolve("./Tipple/app/App_Resources");

var queue = [];

function isImageFile(src) {
    var ext = path.extname(src).toLowerCase();
    return ext === ".jpg" || ext === ".jpeg" || ext === ".png";
}

function resize(src, percent, target, callback) {
    var dir = path.dirname(target);
    if (!fs.existsSync(dir)) {
        fs.mkdirSync(dir);
    }
    console.log(src + " --> " + target);
    im.convert([src, '-resize', percent, target], callback);
}

function processFile(src, callback) {
    var ext = path.extname(src);
    var diff = path.relative(sourcePath, src);
    var target = path.join(targetPath, diff);

    async.series([
        resize.bind(null, src, "24.5%", path.join(targetPath, 'iOS', diff)),
        resize.bind(null, src, "49%", path.join(targetPath, 'iOS', diff).replace(ext, '@2x' + ext)),
        resize.bind(null, src, "73.6%%", path.join(targetPath, 'iOS', diff).replace(ext, '@3x' + ext)),

        resize.bind(null, src, "75%", path.join(targetPath, 'Android/drawable-hdpi', diff)),
        resize.bind(null, src, "50%", path.join(targetPath, 'Android/drawable-mdpi', diff)),
        resize.bind(null, src, "100%", path.join(targetPath, 'Android/drawable-xhdpi', diff)),
        resize.bind(null, src, "70%", path.join(targetPath, 'Android/drawable-xxhdpi', diff)),
        resize.bind(null, src, "93.4%", path.join(targetPath, 'Android/drawable-xxxhdpi', diff))
    ], callback);
}

function processPath(src) {
    var files = fs.readdirSync(src);
    for (var i = 0; i < files.length; i++) {
        var file = files[i];
        var fullpath = path.join(src, file);
        var stats = fs.statSync(fullpath);
        if (stats.isDirectory()) {
            processPath(fullpath);
        } else if (isImageFile(fullpath)) {
            queue.push(processFile.bind(null, fullpath));
        }
    }
}

processPath(sourcePath);
async.series(queue);