Whole stack canvas

[will-moore]

This is a prototype viewer that explores the performance and feature implications of loading a whole stack of Z & T planes into browser memory.
Instead of requesting a plane at a time, we load in batches of up to 10 planes which reduces the number of times we need to initialise Bio-Formats to open the file and read data.
With the data in hand in the browser, we can rapidly scroll through Z & T, do Z/T projections etc.
Also we use the canvas to display images rendered on the fly while adjusting levels with channel sliders.

First TODOs are to handle all image types, sizes, channel count etc.

• Handle non-RGB images (over 3 channels or Red, Green & Blue mixed between channels)
  • Don't render while sliding channels
  • Get single plane on stop sliding (as with current viewer)
• Channels toggling (E.g. start with 2 channels, turn on one (still RGB) and another!)
• Don't load whole stack up-front. Lazy load by default - load all on request / play movie
• Pan image (drag) - only render visible viewport
• Don't support 'Big' images (above max plane size ~ 12k)?