I’ve composed a patch that creates an iris transition. You can position it in x – y space, control the iris size and feather the edge of the mask.
Download Link: iris_quartz_composer.zip
The patch is quite simple to use. For a recent digital puppetry project, I connected the iris radius to a the output of a midi foot pedal so I could create scene transitions in real time. More of that elsewhere.
The patch demonstrates a number of useful ideas: pixel to unit conversion, creating a circle (using the hole distort patch), masks and the ‘source atop-in-out-wave-it-all-about’ patches.
Some Notes on Custom Patches, Hidden Patches and Core Image Units
My original patched originally used one of the hidden patches ‘CICheapBlur’ that you can enable by following instructions here.
For the download here, I have replaced the ‘CICheapBlur’ patch with a gaussian blur – so there shouldn’t be errors if you do not have the ‘hidden’ patches activated. This effects performance slightly. With custom core image filters appearing in the QC patches pane, I am sure it is quite possible to distribute compositions that will not run on other people’s machines without the custom CI filter. There seem to be more useful custom patches appearing on the scene with a number of excellent ones from Boinx. I hope a useful installation mechanism can be constructed to distribute the pre-requiste elements for custom patches.