Encouraging Computational Thinking in Professional Development

Do you ever see something and can’t leave it alone until you figure out how it was made? It happens to me often. In fact, it happened just the other day. I’ve made a ‘spirograph’ application on Scratch, and I was looking at how other Scratchers have coded similar projects. I ran across one in particular that had a beautiful introductory scene. I watched it a few times from the project page before looking behind the scenes in the code.

The animation is composed of layers. The top layer is white rectangle that has cutout letters on it. The bottom layer has a gradient that fades from white to rainbow colors, then to white again. As the bottom layer slides from left to right, the letters are briefly visible. The idea is incredibly simple, and the effect is beautiful. Once I saw it, I had to make my own using letter cutouts to mask a moving layer. For projects like these, projects that involve manipulating shapes and images, I like using Keynote.

The Process (Keynote)

After seeing how the original project was made in Scratch, I wanted to create a title sequence for a video. Of course, there are tools that are made specifically for animating title sequences. I have Motion, for example. But I like making things in more democratic tools. Keynote is a free tool for all Mac and iPad owners and it is easy to use.

I was not working on any particular video at the time, but I had the idea in my mind. I open with a white slide, then the title is briefly visible, then the title scales up and becomes a window. The camera seems to fly through that window into the scene.

I started my Keynote project by creating a white slide with bold black text. I was careful to select a typeface that was bulky throughout. Then I took a screen capture of the slide and pasted it onto a new slide. Using Keynote’s instant alpha tool, I erased the letters, creating open spaces where the letters had been. Then, I created a new rectangle the same height as the erased text on my mask layer. Using the complex gradient setting, I created a rainbow pattern across the rectangle. Then, I moved the rainbow rectangle behind the mask and animated it to move slowly across the screen. I also layered an image behind the rainbow rectangle and used the scale and dissolve animations to give the impression of a window.

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