Phonegap app performance vs native app performance

Question

we are looking at getting a barcode scanning application built. We are considering using PhoneGap but our only worry is speed. All the application will do is just scan a barcode and check a server to see if it's valid or not. The application uses the camera very intensely to scan the barcode via an image. My main question is, will scanning via phonegap be just as fast as a native app? Speed is really important as the user will have to scan multiple barcodes very quickly.

Answer 1

I have developed a smartphone app where barcode scanning is an alternative to the primary function of scanning an image which is recognized by picture matching technology. I use PhoneGap. I have not compared this to native app performance. I am able to say that for my basic UI (it is a web app for the smartphone), my web pages are rendered fast enough not to be an issue. This performance has been observed on a 600MHz smartphone CPU (LG Optimus One running Android 2.2.1).

The picture matching as well as barcode scanning is done on a server backend, not on the smartphone itself. The issue becomes one of networking speed from smartphone over WiFi or service provider network, over the Internet and onto the server - then there is the response from server back to smartphone. The processing speed of picture matching or barcode scanning has to be less than a second (ideally half a second) so that by the time networking delay is added, it is still a 1-2 second response time for the user.

The image files that I am transferring from smartphone to server is targeted to be around 40KB. At a typical 54Mbps WiFi network or the going rate of around 40Mbps in HSPA+ service provider networks, I find the performance of my app to be suitable. Even with a fair signal WiFi speed of 15Mbps, end-user response is acceptable between 1-2 seconds.

The pace of smartphone development (dual core processors) and service provider networks (4G HSPA+) will only take the industry higher. It is a tremendous opportunity for apps development moving forward.

Side Topic: I am using Zbar code on the server for barcode scanning and I am hunting for better alternatives. The challenge with ISBN barcode scanning from smartphones having non-zoom, non-macro lens is that the typical barcode size is too small for "simple" barcode scanning algorithms to work properly. I'd like to hear about alternatives and people's experience with barcode scanning. I would be looking for code that I can deploy in my server backend, as opposed to running smartphone resident barcode scanning.

Answer 2

Phonegap uses the same native APIs, it just abstracts them so that you can write your application in html and javascript. The time to take a picture or any other native process is less important than the time the user perceives. This is the portion of the native execution time that you need to expose to the user + Abstraction API time + UI responsiveness.

There is always an overhead from an abstraction but I think that's negligible in an app like this (in phones newer than BB OS5). The current issues originate from the hardware rendering the HTML and the browser software installed on the device.

A lot of BlackBerry phones don't use webkit (OS5 and below) and the the browsers they do use can seem very sluggish while rendering webapps. BB OS versions less than 5 don't have a production worthy way of communicating between the native and javascript layers, the hack that's often seen is to set and poll for changes in cookies. Android has always had a good design for JavaScript to native interaction afaik.

BlackBerry phones and many lower end Android phones don't have GPU's, or some Android phones that do have GPU's don't compile webkit for the GPU! Without this your UI app may have that sluggish feel, pages/buttons take that bit longer to respond which is very noticeable when you're trying to whiz through menus.

This has improved a lot since phonegap was released. UI lag should continue to decrease to a point where even new low end phones are production ready for webapps. But from my experiences we've not yet reached that point in 2011.

Answer 3

As others noted the html5-based UI may feel sluggish. Maybe it's not an issue; you just have to try it and see. For scanning a barcode and uploading to a server the Phonegap overhead might not be signficant.

Answer 4

The phone's built-in software is what does the scanning and camera action. PhoneGap will only trigger the event and help transfer the data but the phone does all the work.