Using this page to compile all the ideas for the Dual Head support in darktable. Detachable panels is not the only thing that can be done.
The thing is displaying a seconday window that can be moved to the secondary monitor. That window should be a very simple window, with only a center view and upper and botom panels. The upper panel will contain the different modes available in the window (see following) while the bottom panel will contain some utils (lock, zoom level, ...). The modes available will be:
Preview will show a processed full resolution picture of the selected picture in lighttable, and while in darkroom it will update at the same time than the center image is updated. This one should be more or less trivial, but a full res image should be cached after being processed to reduce loading time.
Compare will show two images side by side. The first image (on the left) will be the one selected when activating the mode, and the second one the image selected afterwards. Entering darkroom mode in one of those images will make the one being edited be updated as in preview mode, while the second one remains untouched. By default both images will be locked, so they pan and zoom in a coordinated way, but there should be an unlock option to make them move independently. This compare function would also be available in main window, so users with one monitor only can benefit from it.
- Detachable panels
Detachable panels should also be taken on consideration. Some people like to have the image fullscreen in one monitor while all the tools are in the other. To accomplish this, the UI should be consistent among the modes. (The secondary window has to be the one holding the image, while the main window would hold the panels?) As they are in branch detachable, it shoud be possible to have several right panels detached, showing each one different iop modules, so all used utils can be at hand
Comments from Robert Bieber*¶
I'm a little leery of the notion of having a "secondary" window, mainly because it doesn't really fit in with typical UI conventions. The norm for media applications, as far as I've seen, is break-away panels used to distribute elements of the UI however the user wants them, and I'd tend to think we should try to stay with this convention.
In particular, I'd like to see something similar to GIMP's detachable/combineable panels, but perhaps a little more elegant visually. I think it wouldn't be a bad idea to take a look at GIMP's code and see just how hard it would be to adapt their dockable tabs to Darktable.