Touchup

Quickly mask and collage images.

Features

• Erase by scrubbing with your finger
• Position image with pinch-pan gesture
• Simple, single-screen interface
• Inline help overlay
• Quick undo/redo actions
• Stamp image to background
• Powered by Core Image
• Easy export to camera roll
• Video support

Takeaways

• Learned how to use Core Image shaders
• Learned about exporting buffers from Core Image to Core Video to export video
• Really liked the simplicity of the inline help overlay

Voodoo

Apply and animate shaders on an image or video.

Features

• Easily set up a pipeline of Core Image video effects over a base video or image
• Manipulate effects by binding effect parameters to touches
• Animate and loop changes to effect parameters
• Sequence changes to effect parameters with a step sequencer
• Easily inspect the result of a subset of the pipeline
• Export animation to camera roll
• Use an animation as the base material of a new effect pipeline

Takeaways

• Had a lot of fun playing with this on the subway.
• Limiting the number of effects in the pipeline keeps the user experience simple; allowing the user to "chain" pipelines keeps the tool powerful.
• Easily recording changes with a camera-like interface is fun and easy, but tough to make a clean loop. A quantized sequencer helps to keep things clean.
• The interface for binding parameters to touch input is clunky: it's slow to configure, and doesn't clearly communicate the structure of the bindings. (I implemented the simplest thing, and designed a whole bunch of alternatives. I think there were a couple of slightly better alternatives in the pile; but, in general, I think "patching interfaces" is a tough problem on a small screen.)
• I was idealizing linear bindings from touch position to parameter changes, because I believed direct control would allow the user to get different styles of animation by learning to "perform" those styles (e.g. get a bouncy animation by learning how to gesture bouncily). This is not really possible. Figuring out a way to define non-linear mappings between input and controlled parameters would help make more dynamic animations.

Milkcrate

Create "album art" videos from sound, text, and images.

I made this as a utility to support another video app I was working on. In that app, the user could add a soundtrack by importing sound from a previously-captured video. I used this feature in tandem with iOS's screen recording feature to grab sound from Spotify or YouTube to put into my videos; but it was tough to find a specific sound by scanning my camera roll. Using this app to add "album art" to those soundtrack videos, I could easily find the sounds I wanted.

Features

• Single-screen interface
• Inline help overlay
• Arrange text and background image to create album art
• Export as video to camera roll

Takeaways

• Felt good to turn my camera roll into a slightly more functional file system :)
• Learned more about AVComposition