I've discovered that the canvas.red/green/blue/alphaat expressions are very slow. I tried loading all of the image data into an array (which for a 500x750 image took like 15 minutes!) and discovered retrieving values from an array is far, far faster.
Is there any way that those expressions could be sped up? I know I don't understand how the plugin works behind the scenes, but could the plugin store the image data in an array in addition to or instead of the method it currently uses? Or perhaps could it export the r,g,b and a values as an array to json that could be loaded by the array plugin?
Edit: whoops, it does have to array as json. There seems to be a conflict though, as there are two asJSON expressions (one in the misc category and one in the canvas category), and the second one doesn't seem to be working.
Edit 2: I renamed the expression in the plugin and it doesn't seem to work. The debugger says the array is holding [object Object]. Can you explain how to use it? It said something in the js about that expression being experimental - or maybe I screwed it up by renaming it. If you could get it working or explain how it works, it would be much appreciated! :)