Implement feature rich 2D viewer

[bentoogood]

The primary use of the 2D viewer will be to receive pixels generated by interactive renders. In addition it will be used to display the results of the 2D image processing component.

As this will be the users principle environment for reviewing images within the gaffer app, it should provide a full set of inspection and presentation tools.

Performance (maintaining interactivity) is also a key requirement.

Suggested features (in no order):

• [x] Catalog
  • Thumbnails
  • Re-orderable list
  • metadata attached to each item in catalog (render stats (duration, completion time), camera, etc)
  • Hotkeys for navigation through list
• [x] Interactive gamma/exposure adjustments
• [x] Pixel value inspector
  • Single pixel and region picker. Interactive scrubbing.
  • Results displayable in a range of measurement systems (RGB, HSV, exposure, etc)
  • Option to display values after any display processing is applied (sRGB, LUT etc)
• [x] Image comparison
  • Wipes
  • Diff
  • Easy picking of items from catalog for comparison
• [x] Channel/Layer selection
  • easy preview of individual channels (r,g,b,a)
  • easy selection of individual layers from multilayered image stream (AOVs for example)
• [x] Display processing
  • Easy selection of predefined standard colour spaces (sRGB,rec709)
  • Configurable LUT specification.
• [ ] Selection of scene graph objects from pixel data (special buffer?)
• [x] Crop window
• [x] Data overlay (resolution for example)

[johnhaddon]

There are several different tickets here I think. The Catalogue side of things is definitely a separate thing from the viewer itself to my mind. The Viewer specialises in viewing the output of nodes, and the Catalogue is probably a funky node which outputs different images under different circumstances, and has a Node Editor UI for displaying the catalogue. That's not to say that we can't integrate the Catalogue UI into the Viewer where it helps though - custom toolbars/manipulators per node is obviously going to make the Viewer a much better thing.

I suggest that we break out separate issues for each of the items you listed as we start to address them, and link those subissues back to this larger one.

[thiasbxl]

From a lookdev POV and since we're already using gaffer in production. I'd like to request a few features to be bumped up the priority list :

• Adjusting exposure of the result
• Adding the ability to use a display LUT (also the ability to choose a color space sRGB/Rec709/...)
• Visualizing clipping colors (like in nuke viewer)

Not sure if we'll have this available in a menu but to start with a hotkey-only workflow would do.

Let me know if you would like this in separate ticket.

Thx Mathias

[johnhaddon]

I'd like to take this opportunity to add a mechanism for customisable viewer toolbars - that way I'll have a decent framework for addressing these requests and also the 3d viewer requests that we have on the go...OK with you chaps?

[arvidurs]

I would also have a request for the Crop Region tool to make it a bit more useable. It would be great to be able to move the whole crop region in on go, rather than moving the four edges of the region. And also a reset button (maybe right clicking the crop region button in the viewport).

[johnhaddon]

Closing - the only outstanding item from this mega-ticket is "Selection of scene graph objects from pixel data", which is covered separately by #2674.