Usability of crop tool


(Anton Vakulenko) #1

Hi, All! I’m using Darktable, but just downloaded RT 5.0 on win7 64bit (to give it a try). I know about “strange behaviour” of crop tool in RT comparing to Darktable or Lightroom. But it seems a bit steep. If I crop image and press ALT-F, cropped image “centered” on the screen, but definitely not “fit” the screen. You can see huge black margins around it. And if you press Z to get 1:1 zoom my cropped area hides somewhere from the side (because cropped area is not in the center of image). It’s strange that developers found this behaviour acceptable. It’s definitely not…


(Ingo Weyrich) #2

Fit to screen in rt is always restricted by zoom levels. For example if zoom level 100% does not fit to screen, but 50% fits to screen, 50% will be used even if 75% also would fit to screen, because 75% zoom level does not exist in rt.


(Anton Vakulenko) #3

Hmm… Maybe this algorithm is simple to code… But it seems a strange approach for a such advanced photo tool like RT. This may be not so important on big displays, but on 15’’ and even 17’’ it is very uncomfortable… Almost unusable…

I’m watching on RT for a couple of years but I don’t see much improvement in usability. Looks like developers more interested in implementing new advanced tools for image processing that in “polishing” existing (and not ideal) UI…


(Ingo Weyrich) #4

I understand the issue with small displays and I took a short look at the code:
Currently the restriction is caused by the fact that the reciprocal of the zoom factor has to be integral for reasons. 1/0.75 is not.
Allowing zoom factors like 0.75 would require rewriting a lot of code and also slow down the preview at least for this zoom factors because we would have to resize from e.g. 100% to 75% then. For factors like 1/2, 1/3, 1/4 and so on the processing is much easier and faster.

As usual, pull requests are always welcome :slight_smile:


(Anton Vakulenko) #5

Thank you for clear explanation. I understand re-coding is a headache. But I’m sure all users would highly appreciate some free space for displaying image (regardless of screen size)… :slight_smile:


(Alberto) #6

This sort of works (warning: limited testing!) :slight_smile:
more-zoom-levels.patch (6.9 KB)


(Ingo Weyrich) #7

@agriggio Alberto, very good! Though not continuously variable it allows a lot more zoom levels this way.
I would even add this:
{" 91%", 1.0 / 1.1, 11},


(Alberto) #8

Yes, that was a bit quick’n’dirty :slight_smile:
This one is slightly better. Should I open a proper PR or is the patch enough?
more-zoom-levels.patch (11.5 KB)


(Ingo Weyrich) #9

@agriggio Please open a PR. Maybe we can add the zoom to centre of crop then too.


(Alberto) #10

:thumbsup:

…I’m not sure I understand what you mean though :slight_smile:


(Ingo Weyrich) #11

@agriggio I meant this:


(Alberto) #12

@heckflosse Oh, I see. I missed that completely!