Horizon Straightener Needed

Ideas for improvements and requests for new features in XnView MP

Moderators: XnTriq, helmut, xnview

Post Reply
KiwiB
Posts: 5
Joined: Sun Mar 19, 2017 4:55 am

Horizon Straightener Needed

Post by KiwiB »

Personally I use Photoshop for editing, but I recently encouraged a friend to install XnViewMp as a replacement for his Picasa app. The lack of a horizon leveller was a deal breaker for him, and probably is for many other potential users of the app. The colour adjustments are very satisfactory for his limited purposes, but horizon adjustment is the other essential need for a basic editing suite.
Please consider this for your next update!
User avatar
m.Th.
XnThusiast
Posts: 1663
Joined: Wed Aug 16, 2006 6:31 am
Contact:

Re: Horizon Straightener Needed

Post by m.Th. »

Eh...

Ok. I would be better. Much better IMHO.

...but he can do this now.

Steps:

1. Double-click on an image to open in Viewer
2. Edit | Crop (or press Shift + X)
3. Select an area around the "horizon" - take care to have an edge close to "horizon"
4. Go with the mouse NEAR to the one of the corners of the crop rectangle till you'll see a "rotating" cursor (like "Refresh"). Now you can rotate the crop rectangle.
5. Rotate & adjust till you have the margin exactly parallel with the horizon
6. Expand the margins of the rectangle as desired.
m. Th.

- Dark Themed XnViewMP 1.6 64bit on Win11 x64 -
User avatar
helmut
Posts: 8705
Joined: Sun Oct 12, 2003 6:47 pm
Location: Frankfurt, Germany

Re: Horizon Straightener Needed

Post by helmut »

For straightening an image I'd use custom rotation:

1. Viewer: Image » Rotate » Rotate...
2. Check [x] Show Grid
3. Check [x] Apply to image
4. Change the angle

Though this is a manual process and not an automatic straightening as requested.
cday
XnThusiast
Posts: 3976
Joined: Sun Apr 29, 2012 9:45 am
Location: Cheltenham, U.K.

Re: Horizon Straightener Needed

Post by cday »

helmut wrote:For straightening an image I'd use custom rotation:

1. Viewer: Image » Rotate » Rotate...
2. Check [x] Show Grid
3. Check [x] Apply to image
4. Change the angle

Though this is a manual process and not an automatic straightening as requested.
The problem with that method at present is that the angle adjustment slider is very sensitive, making it hard to make small angle adjustments without using the digital angle display which is slower. Reducing the sensitivity of the slider, or making the sensitivity adjustable in some way, could make precise angle adjustment much easier.

Out of interest, the program ScanTailor widely used for book scan processing has the following interface that allows really quick and easy fine angle adjustment:

ScanTailor_Rotate.png
ScanTailor_Rotate.png (111.25 KiB) Viewed 1237 times
One or other of the blue circles is simply dragged to rotate the image, with a sensitivity that makes it really quick and easy to make accurate adjustments.

But refining the sensitivity of the slider in the existing custom rotation tool would be a good start...

Edit:

Looking at the XnView MP rotate tool in particular, the response to angle changes also seems very slow which makes adjustments even harder. The ScanTailor tool response is almost instantaneous which makes fine tuning really easy.
User avatar
B.Douille
Posts: 258
Joined: Sat Sep 09, 2006 9:25 pm
Location: Hte Savoie - France

Re: Horizon Straightener Needed

Post by B.Douille »

cday wrote:the angle adjustment slider is very sensitive, making it hard to make small angle adjustments without using the digital angle display which is slower
I fully agree with you, the sensisivity of the slider is too high and using the up/down arrow is too slow but I would not recommend to add "yet another" option in the Settings. This is where both our suggestions joints: I like the Scantailor approach, very close to my proposal Improve the Rotation Dialogue that use the existing grid for horizon reference. It's just a matter of look & feel.
cday wrote:the response to angle changes also seems very slow
This may happen with very high resolution images that requires a lot of calculation on slow machines. We may go for an alternate way: Turn the grid to align with the horizon of the picture and rotate the image accordingly only once the mouse button is released. Alternately, the left/right mouse buttons can be use for purpose as well: Left to rotate the image vs the grid and the other to rotate the grid vs the image.
Daniel, promoting XnView since 2004, moved to MP (exclusively) years ago (Platform Windows and Linux Ubuntu)
Jochen S.
Posts: 32
Joined: Sun Nov 05, 2017 12:52 pm

Re: Horizon Straightener Needed

Post by Jochen S. »

+1 for any improvement in rotation :D

Personally I'd prefer the rotate dialog. The disadvantage with the rotated crop window is that when I want to creative rotate an image I need to also rotate my head to get a feeling for the result ;) With the rotation dialog one can preview the result without rotating his head which makes a big difference if one rotates many images.

Jochen
Post Reply