Original report by Marek Mauder (Bitbucket: galfar, GitHub: galfar).

As requested on blog:

Can you explain how to simply find the angle but not rotate using this tool? Since I’m dealing with archival TIFFs I need to keep the DPI and embedded metadata in place, so I’m thinking I would use ImageMagick to rotate once I have the angle. Thanks.

Answer:

For now you could use -l parameter: -l angle: Skip deskewing step if skew angle is smaller And use some large threshold so rotation will always be skipped.

$deskew -l 80 Sken003.png
...
Preparing input image (Sken003.png) ...
Calculating skew angle...
Skew angle found: 0.23
Skipping deskewing step, skew angle lower than threshold of 80.00
Done!

For next version I plan to modify this: angle is optional and if omitted rotation is always skipped.

README says that the license is MIT, but the source files seem to all claim MPL/LGPL. What is actual license of this code? Can you please distribute a license file?

This came up at AUR: https://aur.archlinux.org/packages/deskew-git/

Hello,

After doing some minor testing with the default and the lanczos filters, I agree that the quality under lanczos is noticeably better, and in my old computer, it doesn't take much longer to process (I would say that a couple of seconds per page).

In conclusion, I'd like to use lanczos from now on, but DeskewGui doesn't allow me, to the best of my knowledge, to include parameters when I call deskew.exe.

Is there way I can tell the programme that I want to use lanczos?

Thanks!

Original report by Anonymous.

When trying to deskew landscape images on Windows, the error message:

EImagingError: Error while loading images from file "name of file" <format: tif> Exception message: Access violation

appears.

Original report by Marek Mauder (Bitbucket: galfar, GitHub: galfar).

Received several "complaints" about images after rotation step to be a bit blurry (compared to doing rotation in ImageMagick etc.).

Current "speed over quality" rotation algorithm used in Deskew must be replaced/supplemented with another one.

Original report by Marek Mauder (Bitbucket: galfar, GitHub: galfar).

I get many requests for "process all files in folder" etc. from people not comfortable with command line, shell scripts etc.

Simple GUI frontend (to cmd. line Deskew) with batch processing capability would be nice for many people.

Binaries for Windows, macOS, and Linux required.

The GUI does not currently have an option for this, and I don't know any other way of doing batch image processing with the CLI tool, the default linear filter option blurs the images too much, so it would be nice to be able to change it in the GUI.

Hi, thanks for this program. I think it would be useful to support to deskew a whole pdf file with multiple pages. I normally scan books or documents directly into a multipage pdf file, since it is more manageable to only have one file and not one per page. Do you think that this might be within the scope of this program?

Cheers

Original report by Anonymous.

The default window for DeskewGui is a little too big. In some screens, in particular laptop screens with 1366x800 pixels, it is somewhat difficult to redimension the window because the window title bar is left off screen. The maximum height should be no bigger than about 600 pixels. Thank you for your nice work.

Hello @galfar, I'm your AUR maintainer

I noticed you have a GUI now, but in Scripts there only seems to be a script to compile it on Mac.

I get:

deskewgui.lpr(10,3) Fatal: Can't find unit Interfaces used by deskewgui

Is this usable on Linux?

As GUI will always lag behind a bit and won't provide all the options CLI can handle it may be useful to allow passing extra parameters directly from GUI to CLI.

A new text edit in "Advanced options" should take care of it.

It will be awesome to have more releases a) linux ARM64 and b) macOS-arm64. I would like to use this CLI in linux docker running over Apple M1 computer.

Content rectangle can be auto detected by scanning the image (after thresholding) from the sides and looking where non-white pixels start. If it's fast enough it could be a default setting. If custom content rectangle is passed as a parameter by the user let's not use the detection.

I am looking for a cmd option that can be used to specify the angle that is being calculated before but i was not able to find it in the given set of options. I am applying some preprocessing on same image but has different preprocessed version. But when I run deskew on both of these images I get different skew angles. I want to use same angle for both versions of same image.

Request came in to extend "-b" background color parameter to take it's value from the input image (edge/corner). https://galfar.vevb.net/wp/projects/deskew/comment-page-2/#comment-184847

One request if at all possible is can there be an option for -b that auto samples the rgb value of an edge. I currently run an auto-crop script after they are deskewed and some pages have a different background color. This sometimes trips up the auto crop into thinking the added background is an edge. I’m hoping for something a little more dynamic that allows me to use the tool without sorting the material first.

Hi, you mean something like “look at pixel [0,0] of input image and use it for output background”?

Yes. “look at pixel [0,0] of input image and use it for output background” would be a great additional feature.