I still agree with pixelstuff .... there needs to be a tool similar to Photoshop's Perspective Crop.
Sure you can do it in a VERY round about way with the perspective tool using Source & Destination .... by the way, the GIF above is the first explanation I've seen on how to do it. There should be a Instruction Video on it!!!
BUT, the method is still MUCH MUCH more complex and has many more steps than the Photoshop Perspective Crop. With Photoshop it is 5 steps. Select corner 1 + corner 2 + corner 3 + corner 4 + CROP = DONE
NOW it is straightened, squared, and cropped.
I too like many of the things in Affinity, but I have to go to Photoshop to do perspective cropping. Affinity just doesn't cut it.
I tried haakoo's demonstration on a photo piece I have. I could select the SOURCE. Same as in Photoshop. ... in Photoshop I hit CROP and it's done.
In Affinity, I have to switch to DESTINATION. BUT if I drag to the corners of the original photo as haakoo demonstrates the dimensions of the crop are way out of whack. If I just try to move the corners so everything is squared I can't tell if it is actually squared. The corners aren't clear to being square AND it requires 7 more ADDITIONAL steps to finish ....
Move corner 1 + move corner 2 (is it square?) + move corner 3 (is it square) + move corner 4 (is it square?) + APPLY + Select CROP + adjust CROP to remove the areas not wanted + CROP .... and I'm still not sure that the final image is actually SQUARED off with 90 degree corners.
PLEASE create a Perspective Crop tool !!!!!!!!!!!