iPad Pressure Sensitivity: What it Means to Artists

Posted on July 5, 2010

First, there was the iPad. A touch-screen tablet computer from Apple. There was much rejoicing.

Artists could use this at live events, performing iPad Caricatures, much like many of us do with Live Digital Caricatures.

But there were drawbacks. At first, there was no video feed out to mirror the iPad screen on a larger screen or projector. And second, there was no pressure sensitivity.

Well, problem one was solved by both Sketchbook Pro and now Art Studio (who’s update is currently awaiting Apple’s approval for the screen-out function).

Now, it appears that there is hope for problem two to be solved. The folks over at ten one design have figured out how to get pressure sensitivity from the iPad.

The company first became known for their stylus pens for the iPhone/iPad devices. They also have an interesting program they wrote for the Macbook Pro laptops called Inkwell, that allows pressure sensitivity on the multi-touch pads on the Macbook Pro.

They just recently released a video that shows a tech demonstration of pressure sensitivity on the iPad.

They also solve the problem of the palm contacting the touch screen (called Palm Rejection). Until now, we’ve had to avoid our palm touching the screen or else wear a cotton glove to avoid our palms drawing random lines!

There are still some caveats. Primarily, they do this by using what are called Private APIs. All programming languages have function calls to the core OS called APIs. The available APIs that iPad programmers can use have been tested and allowed by Apple, and are called Public APIs.

However, there are other APIs in the OS. These, non-public APIs (or private APIs) are not allowed in any apps on Apple’s App Store since these APIs are not fully vetted and might have bugs or might pose a security vulnerability.

Since the iPad tech demo of the pressure sensitivity in the video uses the private APIs, we won’t see this in the App Store any time soon.

However, I have a gut feeling that in time, developers will either figure out a way around this by using only public APIs or persuading Apple to release these private APIs to the developers for use.

This is an exciting demonstration and it’s a glimpse into the future of caricature design: