Full-screen inspector: several issues

[Thanatomanic]

@rfranke Thank you for the work on the full-screen inspector in #5593. I like the idea very much, and the execution gets a thumbs up as well!

I have (only) just tested it, and I do have a few points of criticism, that I hope you can address:

1. Serious performance issue: you seem to update the preview as soon as you hover over an image in the file browser (preloading?). This takes up a lot of CPU time and even makes file selection noticeably slower. Since not all users use the preview, they should not experience any performance loss because of it. I would much rather have a preview screen that shows immediately when I press 'f' and then wait a few milliseconds before the image actually shows. Fixed in Extensions of inspector window (#5867) #5872
   Side-note: didn't the 'old' inspector show the embedded JPEG? Maybe I missed it somewhere along the line, but why is the new inspector doing (partial) raw processing instead? My mistake, the JPEG is shown, as can be easily seen when looking at a UniWB file for example.
2. I suppose the sudden lack of the 'Inspector' tab will raise a fair amount of questions to people who casually update RT and have been long time users. What is the best way to ease the transition in your opinion? You can now choose between the old mode and the new mode in Preferences.
3. There seems to be no indication in the GUI of the existence of the full-screen inspector (I find this a downside in darktable as well). Unless I am overlooking something... I think it is bad to have hidden functionality. Could we have a button (per thumbnail I guess?) to open the inspector? This is not without problems of its own...
4. There is a bug/feature: I expect to see a preview of the selected image, but now it shows the preview of the image over which the cursor is positioned when I press 'f'. Intended behavior, conclusion pending. See (8).
5. The behavior of hold-f-to-show and release-f-to-hide unexpectedly changes when you scroll or switch zoom-levels while in full-screen mode: if you do either of those, you enter a permanent full-screen preview and releasing your f or shift-f keys won't make the preview disappear. I don't find this intuitive. I would prefer to either make the preview always disappear as soon as you release the f key, or make the preview state a toggle (this is already mentioned in the PR). I can imagine the latter is also a much more accessibility friendly option.

[from the PR] Panning is possible with a second monitor for the inspector window by moving the mouse over the thumbnail on the first monitor.

6. While it is a nice feature, this implementation would disrupt my usual workflow. I do not want to be forced to move my main window to my second screen to show a full-screen preview on my first screen. I would prefer to have an option in my preferences to indicate on which screen my full-screen preview should show up.

Edit:
7. The documentation on RawPedia should eventually be updated to reflect the new situation. Mental note: this should be a standard thing whenever new functionality is pushed to dev...

[Thanatomanic]

w.r.t. my side-note in (1) and also (7), RawPedia mentions this "The "Inspect" tab shows a preview at a fixed scale of 100% of the image your mouse cursor is hovering over, which is either the largest JPEG image embedded in the raw file, or the image itself when hovering over non-raw images."

[Kildor]

I'm sorry, but where is Inspect panel? It was very usefull feature to literally inspect images, fast and without any additional actions (like pressing any of keys).
Especially if there are several serial images of one object and I need select the best one. I need exact 100% part of image under the cursor, not "an image in unknown scaling but fullscreen". How can I switch back?

I don't have second monitor (especially when I work with notebook) and I don't like this feature at all.

PS: Version: 5.8-2389-g57303d52b

[Thanatomanic]

@Kildor Check this screenshot on RawPedia. The Inspect tab was one of the vertical options on the right.
http://rawpedia.rawtherapee.com/File:Rt_setm_fb.png

[Kildor]

@Thanatomanic, I know what is inspector panel. The problem is there is no more inspector panel in 5.8-2389-g57303d52b and I have to use F, or Shift-F hotkeys just to inspect the image. It used to be much simple action before the update and I hope the bug with missed panel will be fixed.

[rfranke]

I agree that this is a rather big change. The assumption is that one wants to quickly preview the whole image without having to open it in the Editor -- I liked this particular feature e.g. in Darktable.

The panel only showed a fraction of the image, good for inspecting details, but not sufficient to decide which images to remove and which to keep.

There was another issue with MacOS: the panel was always binning 4 screen pixels into one. This made image previews and sorting rather unusable. The new full screen preview exploits the full resolution of a monitor. -- of course only an issue for Mac users ...

The current implementation considers two use cases:

1. single monitor (e.g. laptop): show the image under the mouse on the whole screen when pressing "f" or "shift-f". Support zooming and panning. Hide the image upon release of the "f" key.
2. dual monitor (e.g. laptop + external monitor): show the image on a dedicated monitor. Pin it there with a mouse click. Then update the image as the mouse moves over the thumbs -- as with the panel before.

The update behaviour should not have changed, compared to the side panel. Only the embedded jpeg is shown, not the edited image. CPU load should only increase when the preview is active.

The scaling is known. "f" fills the screen, whereas "Shift-F" is 100%. With a second monitor, the center of the 100% preview can be adjusted by hovering the mouse over the thumb -- as with the panel before, but on another monitor.

I did not do anything to explicitly select a monitor. My preview automatically opens on a second monitor if it was connected during start of RawTherapee. This is similar to e.g. Nikon ViewNX-i.

If people prefer to use the inspect panel, it might be re-added with a configuration option. Changing this option would require a restart of RawTherapee as it is set up during initialisation.

But please give this change a chance first. It does not come out of nothing, but is motivated two other programs I tried and where I found a quick full screen preview very helpful, namely Darktable and ViewNX-i.

[ff2000]

1. single monitor (e.g. laptop): show the image under the mouse on the whole screen when pressing "f" or "shift-f". Support zooming and panning. Hide the image upon release of the "f" key.

I am on a single monitor system. panning doesn't work. Zoomin via scrollwheel works only when pressing "Alt" key simultaniously. Scrollwheel alone scrolls vertically. There is no way to scroll horizontally. Panning via click+drag also doesn't work.

The update behaviour should not have changed, compared to the side panel. Only the embedded jpeg is shown, not the edited image. CPU load should only increase when the preview is active.

But then what is going on in the background? RT-5.8: moving the mouse over the thumbnails produces no real CPU spikes (max 3-4%), with inspect panel open CPU increases to around 100%. RT-dev: Moving the mouse over the thumbnails always increases CPU usage to 100%. I am on a single screen system, so there is no way the preview is shown currently - but this also seems to happen for multi-screen systems as reported by @Thanatomanic

If you want to have a look at art: it also modified the inspect feature, but in a different way. It reduces the file browser to 1 column giving the inspect panel way more space.

[Thanatomanic]

I agree that this is a rather big change. The assumption is that one wants to quickly preview the whole image without having to open it in the Editor -- I liked this particular feature e.g. in Darktable.
The panel only showed a fraction of the image, good for inspecting details, but not sufficient to decide which images to remove and which to keep.

Fully agree here.

The update behaviour should not have changed, compared to the side panel. Only the embedded jpeg is shown, not the edited image. CPU load should only increase when the preview is active.

I recorded two video's of the same situation before c4e2143 (found after bisecting this issue) and of the current dev situation. See this filebin: https://filebin.net/db1sluiuvvf2brol
Pay attention to the output in the console and the CPU usage in File manager (N.B. the total CPU power is high overall because I record the screencast).
Like @ff2000 mentions, clearly the situation is different after that particular commit and processing is happening even though I only hover over images. Interestingly it doesn't seem to happen to all images.

did not do anything to explicitly select a monitor. My preview automatically opens on a second monitor if it was connected during start of RawTherapee. This is similar to e.g. Nikon ViewNX-i.

This is not happening in my case. I cannot show this, because I'm not home atm, but I have two displays and both RT and the preview showed on the same display.
In case of a single display setup, the preview becomes much less useful than the old inspector window, because there is no way to easily browse through your images (you can't point to them). In darktable you can use the mouse scrolling to move forward and backward. Since you've used scrolling for panning, is there any other way to implement going forward/backward?

If people prefer to use the inspect panel, it might be re-added with a configuration option. Changing this option would require a restart of RawTherapee as it is set up during initialisation.
But please give this change a chance first. It does not come out of nothing, but is motivated two other programs I tried and where I found a quick full screen preview very helpful, namely Darktable and ViewNX-i.

I don't think we necessarily need to reintroduce the Inspect panel, but I also think the current situation is too obscured to be found without reading the manual. That is a bad thing imo.

I need to go now, but I want to come back and discuss the behavior of f / shift-f some more as well.

[rfranke]

OK, I see. At the moment the inspector window is always treated as active, in order to always have the most up to date information when opened. This draws a lot of CPU power indeed. I will fix this.

[rfranke]

Regarding zooming and panning: my primary input device was a touchpad found on Mac and newer Windows laptops.

Additionally I tested a mouse with scroll wheel under desktop Linux. My mouse supports left and right click on the scroll wheel that generates horizontal events. Details of event assignment can be changed. The only limitation is that, whenever mouse events and trackpad events overlap, then gestures on a trackpad should work as intended.

[heckflosse]

@rfranke , just for information, not only related to your change (which I personally appreciate, despite of the increas in CPU usage ;-):

I will make some tries on a HP convertible (touch screen) to see how we can use gestures to zoom in/out and so on

[SilvioGrosso]

Hello everyone,

Just tested yesterday's build (RawTherapee_dev_5.8-2397-ge0d3353d7_20200802) on Windows 10
IMHO, this feature is really useful.
Thanks a lot for working on it.

I confirm, on Windows 10, single monitor, the "bug" about the lack of panning when you press F or shift+F.
As already pointed out, to zoom into the image, you need to also press ALT while you rotate your mouse's wheel. It is a bit unconvenient because it adds an extra-step (Alt key).
These are minor glitches and I hope they might be fixed :-)