Crop and resize an image in Titanium, working around image rotation bug (TIMOB-4865)

imagelib.js

/*
	Our library function to resize and crop a photo -- for our needs, we are 
	cropping to a square. Uses the ImageFactory for iOS and ImageUtility module
	for Android to avoid rotation issues, memory leaks, and some crashes due to
	Titanium bugs. Also, we use https://github.com/skypanther/picatsize on Android
	to take the initial photo at or close to the target size to work around
	memory management (out of memory crashes) issues on Android.
*/
var Module = function Class() {};

var ImageFactory = (OS_IOS) ? require('ti.imagefactory') : require('com.alcoapps.imageutility');
var jpgQuality = (OS_IOS) ? ImageFactory.QUALITY_MEDIUM : 60;
var targetPhotoSize = parseInt(Alloy.CFG.photoSize);  // e.g. 1200

Module.prototype.LoadImage = function (event) {
	var blob = event.data.blob;
	if (!blob || blob.apiName !== 'Ti.Blob') {
		return false;
	}

	var origW = blob.width;
	var origH = blob.height;
	var croppedSquareSize = Math.min(origW, origH);
	// defined in our orig code based on device type & orientation -- iOS only because offsets crash Android
	var cropOffsetX = 0;
	var cropOffsetY = 0;

	var imgBlob;
	var fn = 'photo' + guid() + '.jpg';
	var file = Titanium.Filesystem.getFile(Ti.Filesystem.applicationDataDirectory, fn);

	// resize and crop to a square
	if (OS_IOS) {
		// Due to a Titanium bug, if we don't resize with ImageFactory
		// first, then cropping will rotate the image 90 degrees. So, we resize 
		// to its original size here first.
		blob = ImageFactory.imageAsResized(blob, {
			width: origW,
			height: origH,
			quality: ImageFactory.QUALITY_HIGH
		});
		blob = ImageFactory.imageAsCropped(blob, {
			x: cropOffsetX,
			y: cropOffsetY,
			width: croppedSquareSize,
			height: croppedSquareSize
		});
		blob = ImageFactory.imageAsResized(blob, {
			width: targetPhotoSize,
			height: targetPhotoSize,
			quality: jpgQuality
		});
		if (!blob) {
			blob = imgBlob = file = undefined;
			return false;
		}
		imgBlob = ImageFactory.compress(blob, 0.6);
		blob = undefined;
		file.write(imgBlob);
	} else if (OS_ANDROID) {
		// need to crop first, crop to shortest height or width
		blob = blob.imageAsCropped({
			x: 0,
			y: 0,
			width: croppedSquareSize,
			height: croppedSquareSize
		});
		if (!blob) {
			blob = imgBlob = file = undefined;
			return false;
		}
		file.write(blob);
		blob = undefined;

		// Rotate photo in file, resize, and adjust quality.
		ImageFactory.rotateResizeImage(file.nativePath, targetPhotoSize, jpgQuality);

		file = Ti.Filesystem.getFile(file.nativePath);
		imgBlob = file.read();
	}

	if (!imgBlob) {
		blob = imgBlob = file = undefined;
		return false;
	} else {
		return {
			blob: imgBlob,
			nativePath: fn
		};
	}

};

// GUID generator, using e7() from http://stackoverflow.com/a/21963136/292947
var lut = [];
for (var i = 0; i < 256; i++) {
	lut[i] = (i < 16 ? '0' : '') + (i).toString(16);
}

function guid() {
	var d0 = Math.random() * 0xffffffff | 0;
	var d1 = Math.random() * 0xffffffff | 0;
	var d2 = Math.random() * 0xffffffff | 0;
	var d3 = Math.random() * 0xffffffff | 0;
	return lut[d0 & 0xff] + lut[d0 >> 8 & 0xff] + lut[d0 >> 16 & 0xff] + lut[d0 >> 24 & 0xff] + '-' +
		lut[d1 & 0xff] + lut[d1 >> 8 & 0xff] + '-' + lut[d1 >> 16 & 0x0f | 0x40] + lut[d1 >> 24 & 0xff] + '-' +
		lut[d2 & 0x3f | 0x80] + lut[d2 >> 8 & 0xff] + '-' + lut[d2 >> 16 & 0xff] + lut[d2 >> 24 & 0xff] +
		lut[d3 & 0xff] + lut[d3 >> 8 & 0xff] + lut[d3 >> 16 & 0xff] + lut[d3 >> 24 & 0xff];
}

module.exports = new Module();