Proportional panning in full screen view

Ideas for improvements and requests for new features in XnView MP

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Foxyrick
Posts: 10
Joined: Wed Mar 15, 2017 10:32 am

Proportional panning in full screen view

Post by Foxyrick » Sat Apr 18, 2020 6:21 pm

Current behaviour
In the preview window and full screen view mode, when I click and hold to zoom and pan on a picture which is larger than the screen, the picture pans one pixel for each pixel the mouse moves. The mouse effectively drags the picture 1:1 and the cursor can reach the edge of the screen while part of the picture is still off screen, halting the pan. To pan past this, we need to release the mouse button and click the picture nearer the edge, beginning the zoom/pan again.

Suggested behaviour
It would be better, I think (certainly for me), if the panning speed was proportional to the size of the image instead. So, no matter where on the image the zoom/pan was started by clicking, it would be possible to pan across the whole image, edge to edge, in one panning motion. This does not interfere with the positioning of the zoom when clicking, it would only change how much the image pans when the mouse is moved.

The only down side would be a lack of absolute precision in positioning the image (for instance it might be that moving the mouse one pixel moves the image ten pixels). I do not think this would be an issue in practice; it never has been for me before, working with very large images.

I guess I got used to this using a competitor's product, which uses the proportional method. I much prefer XNView MP, regardless 8)
Last edited by Foxyrick on Sun Apr 19, 2020 12:43 am, edited 1 time in total.

cday
XnThusiast
Posts: 2406
Joined: Sun Apr 29, 2012 9:45 am
Location: Cheltenham, U.K.

Re: Proportional panning in full screen view

Post by cday » Sat Apr 18, 2020 6:55 pm

Foxyrick wrote:
Sat Apr 18, 2020 6:21 pm
Suggested behaviour
It would be better, I think (certainly for me), if the panning speed was proportional to the size of the image instead. So, no matter where on the image the zoom/pan was started by clicking, it would be possible to pan across the whole image, edge to edge, in one panning motion. This does not interfere with the positioning of the zoom when clicking, it would only change how much the image pans when the mouse is moved.

The only down side would be a lack of absolute precision in positioning the image (for instance it might be that moving the mouse one pixel moves the image ten pixels). I do not think this would be an issue in practice; it never has been for me before, working with very large images.

In principle it would be possible to have both coarse control, to slew rapidly towards the edge of the image, and fine control to make accurate small adjustments, wouldn't it, possibly by relating panning speed to rate of mouse movement?

I don't know how hard that would be to implement, not too hard I would think?

Foxyrick
Posts: 10
Joined: Wed Mar 15, 2017 10:32 am

Re: Proportional panning in full screen view

Post by Foxyrick » Sat Apr 18, 2020 7:56 pm

Good idea to have both available, but using mouse speed would still give the possibility of reaching the screen edge before the picture edge, if the mouse wasn't moved quickly enough. Then you have to go back, try again... I don't think it would work nicely.

A simpler way to achieve having both 1:1 (fine) and proportional would be to have both selections on the Settings/Interface/Mouse menus. Then, I would do, say, left button for 1:1 pan and right button for proportional pan.

cday
XnThusiast
Posts: 2406
Joined: Sun Apr 29, 2012 9:45 am
Location: Cheltenham, U.K.

Re: Proportional panning in full screen view

Post by cday » Sat Apr 18, 2020 8:27 pm

Foxyrick wrote:
Sat Apr 18, 2020 7:56 pm
A simpler way to achieve having both 1:1 (fine) and proportional would be to have both selections on the Settings/Interface/Mouse menus. Then, I would do, say, left button for 1:1 pan and right button for proportional pan.
True, but a problem with settings is discovering that they exist, new users generally don't browse the large number of options that are already available before posting for help... Would users anticipate that the option might exist?

Good idea to have both available, but using mouse speed would still give the possibility of reaching the screen edge before the picture edge, if the mouse wasn't moved quickly enough. Then you have to go back, try again... I don't think it would work nicely.
I was thinking that fast mouse speed could be proportional to the image pixel dimensions, so that an initial rapid movement in the desired direction would have a large effect and operation might rapidly become intuitive...

In the competitor's product you currently use and are satisfied with, how does it seem to operate?

Foxyrick
Posts: 10
Joined: Wed Mar 15, 2017 10:32 am

Re: Proportional panning in full screen view

Post by Foxyrick » Sun Apr 19, 2020 12:43 am

The competitor's product uses a proportional method. No matter where one clicks to zoom and start panning, the whole picture can be panned with a screen's worth of mouse movement (in the picture's larger dimension compared to the screen, less movement is needed in the smaller dimension). It seems that the amount of picture movement is calculated from the larger screen-relative dimension, and that is used for movement in both dimensions. It's very easy and intuitive, but could be improved upon*. That product also moves the viewport, rather than the picture, so pans in the opposite direction to panning in XNView MP. I'm gradually getting used to that reversal.

*The improvement would be to have a smarter algorithm that does not require a full screen's worth of movement if the picture is only a little bigger than the screen. The one failing of that product's implementation is that you do need to move a full screen's worth (in the larger dimension) to pan from edge to edge even if the picture is only a few pixels bigger than the screen. Although, in that case it gives very fine control, but annoyingly so.

I think most new users would probably not even think there could be a another option for panning speed, happily accepting whatever the default was (leave the default 1:1 so as not to confuse existing users). Unless, like me, they have already seen something different. I checked out the settings before posting here, just in case.

I still don't think making it mouse-speed dependent would be good. If one does not move the mouse quickly enough the first time, it will require another attempt. Maybe I'm wrong but I just cannot imagine it being as intuitive as the simpler, image size only related option.

...

To add to my OP, the same system would be useful in the preview window as well. I just tend to use full screen view a lot so I didn't think about preview at first.

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