Inking on the iPad


As a follow-up to my review of iAnnotate, I did a quick exploration of drawing apps available for the iPad to understand the limitations of ink handling on the device. I tried five free annotation apps that were identified by the query “draw free for ipad.” These included Draw Free for iPad, PaperDesk LITE for iPad, Adobe Ideas 1.0 for iPad, Draw for iPad, and Doodle Buddy for iPad.

These apps were structured either around the canvas or the notepad metaphor, and supported a range of colors, inks, and effects. My only test was to select the thinnest ink the tool allowed, and to try to write a short phrase on each one. The test was purely visual, but then it’s the visual impact that I am interested in.

The results were unsurprising: none of the apps managed to capture the ink fast enough to capture even rather methodical cursive handwriting, suggesting that the limitation is in the speed of the CPU rather than in the cleverness of the programmers. In the case of the Adobe app, the cleverness of the programmers compensated a bit for the lack of CPU power: that app applies some sort of spline smoothing to each stroke to compensate for the sharp corners caused by the low sampling rate. This certainly made the ink look nicer, but actual stylus tracking was still problematic.

Here are the samples:

Draw sample

Draw Free sample

Drawing Buddy sample

PaperDesk LITE sample

Adobe Ideas sample

In each case, I picked the thinnest ink; thicker ink can be made to look smoother, but takes up more space on the screen, which is undesirable for annotating documents. The smoothing in the Adobe Ideas example made the text look nicer, but also made the letters seem more angled, somehow.

In any case, while the ink samples of Drawing Buddy and PaperDesk LITE are at least somewhat legible, keep in mind that all samples shown represent about 45% of the total width of the tablet in portrait mode. This size is hardly useful for note taking, much less so for annotating documents in the margins.

For comparison, I pulled out my old Fujitsu Stylistic ST4110 slate (I’ve had it since late 2002), and did the same test on it, using the Windows Journal software, and XLibris in the notebook view. The tablet screen has the same number of pixels as the iPad (on a 10.4″ screen vs. 9.7″ for iPad), making the comparison plausible.

Windows Journal on a TabletPC sample

XLibris notebook view on a TabletPC sample

Both of these are much better looking and easier to write (and thus smaller) due to a less slick surface. In fact, I had forgotten how it felt to write on the Tablet PC, and it was a pleasant shock at how good it felt compared to the iPad. And I could rest my hand on the screen without inducing epileptic fits in the inking code! The iPad of course is a smaller, lighter device with a battery lifespan that’s 2-3 times that of the tablet, so I am not suggesting that the older machine is inherently superior, but it does suggest that not all applications benefit from the tradeoffs made by the iPad engineers.

The upshot is that while coarse marking (such as circling or margin bars) are quite doable on the iPad, handwritten notes are not really possible given the current hardware. This limits active reading applications that may be built on this platform until system responsiveness improves. Even in that case, however, the lack of a good stylus and the inability to rest one’s palm on the screen while writing will hamper people’s ability to write on the iPad.

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  1. I recently looked into sketching on the iPad with a capacitive stylus (Ten One Design Pogo). The stylus has a fairly thick tip but feels comparable to drawing with a Sharpie permanent marker. The real problem is the lack of palm rejection in the available drawing applications. Writing/sketching without being able to support one’s hand on the surface is both uncomfortable and imprecise.

  2. Yeah, that’s the same stylus I was using, and I had the same experience. While the finger is a good pointing device in that it is relatively hard to misplace, for some tasks, a stylus that the computer can distinguish from the finger (or palm or nose, or whatever other part of your body you chose to point with) can make interaction richer and more precise.

  3. […] on the iPad Inking on iPad by FXPAL […]

  4. Ralph Jacob, Ph.D. says:

    Oh my! Your query was inadequate. Your post contains many errors; most notably, you missed Penultimate, which is probably the best note taking inking application for the iPad currently. Think before you speak applies to blog posts as well.

  5. Thank you for pointing out Penultimate to me. Although my query for this post was specifically for free annotation tools, I will take a look at Penultimate.

    I would be grateful if you pointed out the many other errors as well.

  6. […] try to understand the software limitations of inking on the iPad, I had earlier described an ad hoc writing experiment I had conducted on some free iPad applications designed for drawing. […]

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