Photo: Rotating Objects/Layers in steps of 0,01 degree

[max1josef]

It is possible to increase/decrease the rotation angle of an object using the scroll wheel of your mouse when hovering over the belonging input field (in steps of 1 degree).

With 'Ctrl' pressed, the increment/decrement is 0.1 degree, which is already very helpful.

Question: Is there a way to get an even finer increment/decrement of 0.01 degrees?

(I often have to align scanned images, where finer rotation steps would prove useful)

[v_kyr]

What should 1/100 degree bring here optically/visually great, further AFAIK these are rounded up or down anyway to 1/10 values? - So check first the user interface prefs settings for "decimal places for unit types", if it would allow you to setup such a finer precision here at all for degrees.

[thomaso]

I don't know the answer (and wonder, too, how you would detect the required angle in this precision?) … but possibly you could use other solutions, for instance…:

• Some scan programs offer an automatic rotation adjustment (horizontal orientation) for the scan result, while the feature may be hidden in the interface, e.g. behind "advanced" options.

• Depending on the scanner model you could alternatively use a separate scan software that includes this feature. Those that offer auto-frame-detection quite likely include auto-rotation, too. (Possibly even one of many free / open source software offers auto-rotation? https://fixthephoto.com/best-free-scanner-software.html )

• Also there are image editing apps that offer auto-rotation (+ auto-crop), especially if the scanned image shows text, for instance: https://www.klippa.com/en/blog/information/automatically-rotate-documents-images-and-pages/

[max1josef]

First of all: I mentioned the wrong program in the initial post, it's actually Photo.

My workflow: I regularly scan fotos or drawings which are to small for my A4-Scanner. So I scan 2 ore more subpictures with overlap. I load the subpicture into Photo, put one into the background make the other one semi-transparent and position it correctly with regard to the background image using a distinct detail in the picture. Then I rotate the half-transparent picture in fine rotation steps. Having the background and the half-transparent image in view at the same time you can be very, very precise here.

For the time being, I rotate in steps of 0,1 until I'm almost there, then add/substract manually 0,01 degree steps and after one to three retrys I'm there. Not a big deal, but would be more comfortable to be able to rotate in 0,01 degrees in the first place.

PS: Auto-Rotate of scan programs does not work precisely enough, especially when there are no suitable reference lines in both subparts.

[carl123]

You can create a single macro to rotate by 0.01 degrees

Or create a series of macros like....

Rotate 0.01 degrees
Rotate 0.02 degrees
Rotate 0.03 degrees
Rotate 0.04 degrees
Rotate 0.05 degrees

[GarryP]

I just placed a 5594×3729 pixel image (20.8MP?) into a document and rotated it by 0.01 degrees about the centre.

The measurement from the bottom-left corner of the original to the bottom-left corner of the rotated copy is approximately 0.5 pixels.

It would be interesting to see how the export process would cope with that in a way which gave a meaningfully-different result.

Note: Photo’s Crop functionality has a Straighten mode which might be useful.

[max1josef]

I'm already using my workflow with success. It may sound over-accurate, but when combining images it's worth the effort. 

The only improvment I'm looking for is the way how to enter the rotation values.

@carl123

Thanks for the suggestion, I have not thought of macros at all!

[Paul Mudditt]

On 7/31/2023 at 1:14 PM, max1josef said:

First of all: I mentioned the wrong program in the initial post, it's actually Photo.

My workflow: I regularly scan fotos or drawings which are to small for my A4-Scanner. So I scan 2 ore more subpictures with overlap. I load the subpicture into Photo, put one into the background make the other one semi-transparent and position it correctly with regard to the background image using a distinct detail in the picture. Then I rotate the half-transparent picture in fine rotation steps. Having the background and the half-transparent image in view at the same time you can be very, very precise here.

For the time being, I rotate in steps of 0,1 until I'm almost there, then add/substract manually 0,01 degree steps and after one to three retrys I'm there. Not a big deal, but would be more comfortable to be able to rotate in 0,01 degrees in the first place.

PS: Auto-Rotate of scan programs does not work precisely enough, especially when there are no suitable reference lines in both subparts.

Did you try using the panorama feature instead, that can work on scanned data as well as scenery instead of trying to do this manually? I often do this on maps.

[max1josef]

On 9/22/2023 at 1:48 PM, Paul Mudditt said:

Did you try using the panorama feature instead, that can work on scanned data as well as scenery instead of trying to do this manually? I often do this on maps.

Wow this works really great and flawlessly! What a savings of tedious editing and time! Thank you so much, you made my day!  What do I say, you have made my week, month and year! 😀👍🏆

Some years ago (didn't have Affinity at this time) I tried the same with PTGui panoram stitcher. But PTgui cannot handle images without lens information properly and produced weird distortions. Since than I didn't even think of using a panorama stitcher for this purpose.

[Paul Mudditt]

30 minutes ago, max1josef said:

Wow this works really great and flawlessly! What a savings of tedious editing and time! Thank you so much, you made my day!  What do I say, you have made my week, month and year! 😀👍🏆

Some years ago (didn't have Affinity at this time) I tried the same with PTGui panoram stitcher. But PTgui cannot handle images without lens information properly and produced weird distortions. Since than I didn't even think of using a panorama stitcher for this purpose.

Glad you like it !