Transform object with arbitrary handles inside object

[Utruiwe]

I often have to scale and skew a photo with regards to an object within the photo. For example I know the dimensions of a rectangle in the photo, and I now want to scale and skew the photo so this rectangular object is straight and in the right scale. Since the object may not be all that large in regards to the entire picture frame, being able to work zoomed in would be good. However when zoomed in, I cannot access any of the transformation handles. Gimp has a tool called "handle transform" that allows to place arbitrary handles in a picture and transform using those. Is there a similar capability in any of the Affinity applications?

Below is an example: Assuming I want to de-skew this picture of a notebook keyboard with the ruler as a reference. As far as I know how to do this in Affinity, it takes 10 times as long as it should: iteratively plucking the picture to size and shape with the perspective tool and move is a pain! Any handle moves all reference points in the image, I have to zoom in to actually judge the alignment and zoom out again to access the handles.

In Gimp I place three handles on the ruler, drag them onto the right grid point and am done. Unfortunately, Gimp as a lot of other issues and I would really like to be able to do this efficiently in Affinity.

Can anyone tell me the "right" way to do this in Affinity?

[Komatös]

Hello @Utruiwe and welcome to the forums.

From the tools select the Crop Tool . From the context menu select Straighten or Rotate for alignment. After that you can crop the object. If you are satisfied with the selection click on Apply.

[thomaso]

2 hours ago, Utruiwe said:

For example I know the dimensions of a rectangle in the photo, and I now want to scale and skew the photo so this rectangular object is straight and in the right scale.

After you de-skewed the image … you can scale it accordingly in three steps:

1. Use the Vector Crop Tool and limit its width to a known length, e.g. the distance 0 cm ->  5 cm on the ruler in your photo:

2. Switch to the Move Tool and select the Image layer:

3. Enter the known 5 cm (50 mm) in the Transform Panel, lock the aspect ratio and press the Enter key:

Now you can delete the nested, cropping rectangle (or use it to adjust the cropped detail).