Back to Apping: Creepy Hands, Part 1


Once your masterpiece app is finished, there remain some irritating stumbling blocks on your way to the App Store. One of these is the product video.

A screenshot may tell a thousand words, but a good video can replace a fair few screenshots, and won’t require your potential beloved customers to scroll. Did I mention I hate scrolling?

You might suppose that the only challenge in the creation of a product video is to find software to record your screen. Unfortunately, this is the easy part. The difficult part is finding software that will also record your hand movements while your finger is still hovering above the screen.

Solution 1: use another device to take a video of yourself actually using the app!

This is a messy solution at best. Good luck to you if you want to do this. If you don’t have creepy hands, if you can eliminate reflections, sort out the lighting and background, and if you have good video after-effects software then this might work well enough.

Solution 2: Add a virtual finger (or hand) afterwards with after-effects software!

This may be a bit easier than Solution 1, and it should look neater. I almost researched this idea but decided that, if I were to make dozens of videos, it would take too long. In addition to the potentially prohibitive cost of after-effects software.

Solution 3: Draw the actual finger (or hand) in-app!

This was my favoured solution, because it’s more of a coding challenge. It does not require learning any other skills, or purchasing any other fancy software.

I tried to remember how I solved this problem before, years ago, for my previous apps (which are now lost in time). I had a vague memory of taking a photo of my hand and employing that as a makeshift cursor. Then using the simulator to record everything.

Why didn’t I take a look at my old code? Well, because coders like me really don’t like doing that. Nobody should want to peruse the horrible code of our less-experienced selves. We much prefer writing shiny new code.

But anyway, the first step was to photograph my hand. I wanted two top-down shots of a pointing index finger, with one of them simulating the tap motion.

You won’t believe how wretchedly difficult this is to do. Because, the thing is, I needed to have a background which I could magic away quickly in software. Yet no matter what colour card I had underneath my hand, masking this out in one go proved extremely difficult, due to shadows and skin reflections and weird optical illusions like this one.

In the end, I thought back twenty-five years. My preference back then was never to use photo-manipulation software. It was to use vector software and manually mask out the image, using straight lines and Bézier curves. This is what I did (thanks, Inkscape).

So, coding a hand for a cursor is trivial. It’s not a proper cursor, of course, rather it’s an image that has its origin at the pad of the index finger and follows the mouse around. But here was my new problem:

My hand looked extremely creepy as a cursor.

Yeesh. I’ve spared you the two other colours I used as backgrounds. Notice the shadows above the knuckles? That’s where bitmap software fails. Vector software meanwhile loses hairs, but that’s the least of things, as far as creepiness is concerned.

I had to ask myself: was my hand always this creepy? I know I’m no spring chicken but that thing was like something out of Tales of the Crypt. Does my hand really look like that in real life?!

Well, it wouldn’t do at all, and I didn’t want to go through that whole process again with someone else’s hand. What if their hand turned out to be just as creepy as mine? On the other hand (ahem), what if it looked great and I ended up with a complex about my own general hideousness.

So, my next thought was to draw a cartoon hand. Well, actually, not a hand: a glove. If it’s good enough for Bugs Bunny then it’s good enough for me. Now, I could draw this with pencil on paper and then scan it in and that would surely have been the best solution.

But then (unfortunately) I had another idea, and it was this: I should really draw this hand in code…

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