Ejecta's cameraRoll picker sample code.

index.js

var canvas = document.getElementById('canvas');
var w = canvas.width = window.innerWidth;
var h = canvas.height = window.innerHeight;
var ctx = canvas.getContext('2d');
ctx.fillStyle = '#000000';
ctx.fillRect(0, 0, w, h);
ctx.fillStyle = "#ffffff";
ctx.fillText('Tap the screen to open the photo library', 0, 20);

document.addEventListener('touchend', function (ev) {

	var imagePicker = new Ejecta.ImagePicker();

	// all options are optional
	var options = {
		sourceType     : 'PhotoLibrary',              // 'PhotoLibrary' or 'SavedPhotosAlbum' (or experimental 'Camera')

		popupX         : ev.changedTouches[0].pageX,  // Popup position, relevant only on iPad when sourceType is not Camera,
		popupY         : ev.changedTouches[0].pageY,  // best value is the tap coordinates or the center of the tapped element

		popupWidth     : 1,                           // Popup size, 1 for minimal size allowed,
		popupHeight    : 1,                           // relevant only on iPad, when sourceType is not Camera

		maxWidth       : w,                           // Max image size (resolution), by default it's GL ES max texture size
		maxHeight      : h                            // ..
	};

	// Setting the 'sourceType' to 'camera' is experimental because:
	//   - an iPad app in portrait mode only presents the camera interface in landscape no matter what
	//   - it have not been tested on a large enough number of different devices / iOS versions
	//   - internet seems to report more strange camera orientation behaviors depending of the device / iOS version
	//   The right way to access and retrieve a picture from the camera seems to be the usage of ObjC's AVCam library
	//   instead of UIImagePicker, and would require another specific EJbinding oriented on the camera.
	//   This beeing said, this option is here because it works well in some particular cases (like an iPhone's portrait
	//   only application) and because Ejecta doesn't provide yet any another way to access the camera. But if you are
	//   using it, it's at your own risk :).

	// Note: on iPhone the image picker is displayed on portrait mode only. This is an Apple requirement:
	//   "The UIImagePickerController class supports portrait mode only. This class is intended to be used as-is and
	//   does not support subclassing."
	//   There is some hacks around to override this behavior, but because Apple may reject your app if you do this
	//   and because those hacks are not easy to implement on all iOS/devices, they are not available in this EJbinding.

	imagePicker.getPicture(function (error, image) {
		if (error) {
			return console.log('Loading failed: ' + error);
		}
		ctx.drawImage(image, 0, 0);

	}, options);

}, false);