Usefulness of Preview mode

[sidequestboy]

As I understand it, double-clicking on a thumbnail, or pressing Enter while a thumbnail is selected, in the GTK window sets the background, but will not restore to it on reboot, etc.

I don't understand why this "Preview" mode is needed in the GUI, or why anyone would want to preview a background without having it persist in their next sessions.

It would be nice to have one less action before the desktop is set persistently. Could we make the action of double-click and Enter be the same as the Apply button, maybe keeping the Apply button for accessibility?

[Hjdskes]

I find this preview very handy and I would prefer it to stay.

[sidequestboy]

With the code prior to this pull request, the only functionality the preview mode added as far as I could tell was reverting to a saved state you had in a previous session, which IMO is unexpected, and as far as I can see is useless behaviour.

With the code from that pull request, the behaviour is much more sane IMO (still using preview mode, reverts to saved mode on Nitrogen close if changes not saved), but the question remains of whether the preview state is useful or not.

If you are referring the way it acts presently, or something else, could you elaborate on what you find handy?

[Hjdskes]

I agree in your other Issue that when you did not apply a wallpaper, it should revert to the one you currently have when Nitrogen exits.

However, when I want to change my wallpaper I often cycle through a few of them before deciding. I find the preview very handy for this, in case I decide my old one is better.

[sidequestboy]

Currently, there are 3 distinct states:
A. Thumbnail selected
B. Wallpaper previewed
C. Wallpaper applied

I have 3 propositions that I believe would be better than current behaviour;
let me know what you think of each:

1. Merge A and B. (keep preview mode)
   • Have single-click/arrow-navigate immediately preview the wallpaper
   • Have Enter/Apply Button/double-click save/apply the wallpaper
   • This still keeps the advantage of storing the previous state as you describe in your use case, but makes the application feel IMO lighter.
2. Merge B and C. (remove preview mode)

• Have single-click/arrow-navigate select the wallpaper without previewing
• Have Enter/Apply Button/double-click save/apply the wallpaper

3. Merge A, B, and C (only apply mode)

• Have single-click/arrow-navigate immediately preview the wallpaper, then save/apply the wallpaper without prompt on exit

[daf]

I had actually planned on option 1 being in 1.6 - the double click to do the preview was a poor choice when I first implemented it and inconsistent with many other applications. Preview is very useful to me (and others), and #32 helps clean up a rough edge.

I had a proof-of-concept "nav" branch that I worked on years ago and never really fully got working, but it had the idea of a preview history with back and forth like navigating a webpage. I thought the UI was a little clunky but might be a useful feature to some. I have no plans to put that in soon, however.

[daf]

One thing to do when implementing single-click preview/double-click save is to make sure the UI gives feedback to know that a save has taken place - I'm not sure what the best mechanism is for such a thing. Do you have any ideas?